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Sample records for resonance imaging mri

  1. Abstract--Magnetic Resonance Imaging (MRI) guided nanorobotic systems that could perform diagnostic, curative

    E-Print Network [OSTI]

    Mavroidis, Constantinos

    groups have employed magnetized micro/ nanoparticles and have implemented magnetic propulsion techniquesAbstract-- Magnetic Resonance Imaging (MRI) guided nanorobotic systems that could perform on the use of a MRI scanner to induce the required external driving forces to guide magnetic nanocapsules

  2. Safety Guidelines for Conducting Magnetic Resonance Imaging (MRI) Experiments Involving

    E-Print Network [OSTI]

    California at San Diego, University of

    & an approved Informed Consent form. For animal studies, provide the Center with approval letter from the UCSD Institutional Animal Care and Use Committee. (4) Establish an experimenter research file and subject screening (MRI) center is dedicated solely for research. It is not a medical facility. The center houses three

  3. An Atlas-Based Electron Density Mapping Method for Magnetic Resonance Imaging (MRI)-Alone Treatment Planning and Adaptive MRI-Based Prostate Radiation Therapy

    SciTech Connect (OSTI)

    Dowling, Jason A., E-mail: jason.dowling@csiro.au [Australian e-Health Research Center, CSIRO ICT Commonwealth Scientific and Industrial Research Organisation Information and Communication Technologies Centre, Queensland (Australia); Lambert, Jonathan [Calvary Mater Newcastle Hospital, New South Wales (Australia); University of Newcastle, New South Wales (Australia); Parker, Joel [Calvary Mater Newcastle Hospital, New South Wales (Australia); Salvado, Olivier; Fripp, Jurgen [Australian e-Health Research Center, CSIRO ICT Commonwealth Scientific and Industrial Research Organisation Information and Communication Technologies Centre, Queensland (Australia); Capp, Anne; Wratten, Chris; Denham, James W.; Greer, Peter B. [Calvary Mater Newcastle Hospital, New South Wales (Australia); University of Newcastle, New South Wales (Australia)

    2012-05-01

    Purpose: Prostate radiation therapy dose planning directly on magnetic resonance imaging (MRI) scans would reduce costs and uncertainties due to multimodality image registration. Adaptive planning using a combined MRI-linear accelerator approach will also require dose calculations to be performed using MRI data. The aim of this work was to develop an atlas-based method to map realistic electron densities to MRI scans for dose calculations and digitally reconstructed radiograph (DRR) generation. Methods and Materials: Whole-pelvis MRI and CT scan data were collected from 39 prostate patients. Scans from 2 patients showed significantly different anatomy from that of the remaining patient population, and these patients were excluded. A whole-pelvis MRI atlas was generated based on the manually delineated MRI scans. In addition, a conjugate electron-density atlas was generated from the coregistered computed tomography (CT)-MRI scans. Pseudo-CT scans for each patient were automatically generated by global and nonrigid registration of the MRI atlas to the patient MRI scan, followed by application of the same transformations to the electron-density atlas. Comparisons were made between organ segmentations by using the Dice similarity coefficient (DSC) and point dose calculations for 26 patients on planning CT and pseudo-CT scans. Results: The agreement between pseudo-CT and planning CT was quantified by differences in the point dose at isocenter and distance to agreement in corresponding voxels. Dose differences were found to be less than 2%. Chi-squared values indicated that the planning CT and pseudo-CT dose distributions were equivalent. No significant differences (p > 0.9) were found between CT and pseudo-CT Hounsfield units for organs of interest. Mean {+-} standard deviation DSC scores for the atlas-based segmentation of the pelvic bones were 0.79 {+-} 0.12, 0.70 {+-} 0.14 for the prostate, 0.64 {+-} 0.16 for the bladder, and 0.63 {+-} 0.16 for the rectum. Conclusions: The electron-density atlas method provides the ability to automatically define organs and map realistic electron densities to MRI scans for radiotherapy dose planning and DRR generation. This method provides the necessary tools for MRI-alone treatment planning and adaptive MRI-based prostate radiation therapy.

  4. Breast density quantification using magnetic resonance imaging (MRI) with bias field correction: A postmortem study

    SciTech Connect (OSTI)

    Ding, Huanjun; Johnson, Travis; Lin, Muqing; Le, Huy Q.; Ducote, Justin L.; Su, Min-Ying; Molloi, Sabee

    2013-12-15

    Purpose: Quantification of breast density based on three-dimensional breast MRI may provide useful information for the early detection of breast cancer. However, the field inhomogeneity can severely challenge the computerized image segmentation process. In this work, the effect of the bias field in breast density quantification has been investigated with a postmortem study. Methods: T1-weighted images of 20 pairs of postmortem breasts were acquired on a 1.5 T breast MRI scanner. Two computer-assisted algorithms were used to quantify the volumetric breast density. First, standard fuzzy c-means (FCM) clustering was used on raw images with the bias field present. Then, the coherent local intensity clustering (CLIC) method estimated and corrected the bias field during the iterative tissue segmentation process. Finally, FCM clustering was performed on the bias-field-corrected images produced by CLIC method. The left–right correlation for breasts in the same pair was studied for both segmentation algorithms to evaluate the precision of the tissue classification. Finally, the breast densities measured with the three methods were compared to the gold standard tissue compositions obtained from chemical analysis. The linear correlation coefficient, Pearson'sr, was used to evaluate the two image segmentation algorithms and the effect of bias field. Results: The CLIC method successfully corrected the intensity inhomogeneity induced by the bias field. In left–right comparisons, the CLIC method significantly improved the slope and the correlation coefficient of the linear fitting for the glandular volume estimation. The left–right breast density correlation was also increased from 0.93 to 0.98. When compared with the percent fibroglandular volume (%FGV) from chemical analysis, results after bias field correction from both the CLIC the FCM algorithms showed improved linear correlation. As a result, the Pearson'sr increased from 0.86 to 0.92 with the bias field correction. Conclusions: The investigated CLIC method significantly increased the precision and accuracy of breast density quantification using breast MRI images by effectively correcting the bias field. It is expected that a fully automated computerized algorithm for breast density quantification may have great potential in clinical MRI applications.

  5. Safety Guidelines for Conducting Magnetic Resonance Imaging (MRI) Experiments Involving Human Subjects UCSD Center for Functional MRI, April 4, 2008

    E-Print Network [OSTI]

    California at San Diego, University of

    Subjects UCSD Center for Functional MRI, April 4, 2008 NOTE: These safety guidelines supplement and update the main safety guidelines from July 2007. Guidelines 1 through 6 apply to all subjects and studies. 1) For all subjects and studies, a safety-certified adult should continuously monitor the subject's status

  6. Model-based reconstruction of magnetic resonance spectroscopic imaging

    E-Print Network [OSTI]

    Chatnuntawech, Itthi

    2013-01-01

    Magnetic resonance imaging (MRI) is a medical imaging technique that is used to obtain images of soft tissue throughout the body. Since its development in the 1970s, MRI has gained tremendous importance in clinical practice ...

  7. Simultaneous PET/fMRI for imaging neuroreceptor dynamics

    E-Print Network [OSTI]

    Sander, Christin Y. (Christin Yen-Ming)

    2014-01-01

    Whole-brain neuroimaging is a key technique for studying brain function and connectivity. Recent advances in combining two imaging modalities - magnetic resonance imaging (MRI) and positron emission tomography (PET) - into ...

  8. Magnetic resonance imaging in cardiovascular disease 

    E-Print Network [OSTI]

    Richards, Jennifer Margaret Jane

    2013-07-06

    Background Superparamagnetic particles of iron oxide (SPIO) are part of a novel and exciting class of ‘smart’ magnetic resonance imaging (MRI) contrast agents that are taken up by inflammatory cells. Ultrasmall SPIO ...

  9. Magnetic resonance imaging contrast agents for chemical sensing

    E-Print Network [OSTI]

    Liu, Vincent Hok

    2014-01-01

    Magnetic resonance imaging (MRI) is frequently used for examining the human body. MRI contrast agents currently used in the clinic assist physicians in locating problematic areas, but other tools are needed to interrogate ...

  10. Methods for chemical exchange saturation transfer magnetic resonance imaging

    E-Print Network [OSTI]

    Scheidegger, Rachel Nora

    2013-01-01

    Chemical exchange saturation transfer (CEST) is a relatively new magnetic resonance imaging (MRI) acquisition technique that generates contrast dependent on tissue microenvironment, such as protein concentration and ...

  11. In vivo imaging with a cell-permeable porphyrin-based MRI contrast agent

    E-Print Network [OSTI]

    Lee, Taekwan

    Magnetic resonance imaging (MRI) with molecular probes offers the potential to monitor physiological parameters with comparatively high spatial and temporal resolution in living subjects. For detection of intracellular ...

  12. In Vivo Imaging with a Cell-Permeable Porphyrin-Based MRI Contrast

    E-Print Network [OSTI]

    Lee, Taekwan

    Magnetic resonance imaging (MRI) with molecular probes offers the potential to monitor physiological parameters with comparatively high spatial and temporal resolution in living subjects. For detection of intracellular ...

  13. Differences in span task performance recorded in a functional magnetic resonance imaging (fMRI) simulator compared to a standard laboratory condition 

    E-Print Network [OSTI]

    Harcourt-Brown, Sally

    2006-01-01

    Forty-eight participants completed a working memory span task in a functional magnetic imaging (fMRI) simulator and laboratory. Differences in performance between the two conditions were investigated. The trends in the ...

  14. Designing and characterizing hyperpolarizable silicon nanoparticles for magnetic resonance imaging

    E-Print Network [OSTI]

    Anahtar, Melis Nuray

    2008-01-01

    Magnetic Resonance Imaging (MRI) is one of the most powerful noninvasive tools for diagnosing human disease, but its utility is limited because current contrast agents are ineffective when imaging air-tissue interfaces, ...

  15. Design algorithms for parallel transmission in magnetic resonance imaging

    E-Print Network [OSTI]

    Setsompop, Kawin

    2008-01-01

    The focus of this dissertation is on the algorithm design, implementation, and validation of parallel transmission technology in Magnetic Resonance Imaging (MRI). Novel algorithms are proposed which yield excellent excitation ...

  16. Tumor Metabolism and Perfusion in Head and Neck Squamous Cell Carcinoma: Pretreatment Multimodality Imaging With {sup 1}H Magnetic Resonance Spectroscopy, Dynamic Contrast-Enhanced MRI, and [{sup 18}F]FDG-PET

    SciTech Connect (OSTI)

    Jansen, Jacobus F.A.; Schoeder, Heiko; Lee, Nancy Y.; Stambuk, Hilda E.; Wang Ya; Fury, Matthew G.; Patel, Senehal G.; Pfister, David G.; Shah, Jatin P.; Koutcher, Jason A.; Shukla-Dave, Amita

    2012-01-01

    Purpose: To correlate proton magnetic resonance spectroscopy ({sup 1}H-MRS), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and {sup 18}F-labeled fluorodeoxyglucose positron emission tomography ([{sup 18}F]FDG PET) of nodal metastases in patients with head and neck squamous cell carcinoma (HNSCC) for assessment of tumor biology. Additionally, pretreatment multimodality imaging was evaluated for its efficacy in predicting short-term response to treatment. Methods and Materials: Metastatic neck nodes were imaged with {sup 1}H-MRS, DCE-MRI, and [{sup 18}F]FDG PET in 16 patients with newly diagnosed HNSCC, before treatment. Short-term patient radiological response was evaluated at 3 to 4 months. Correlations among {sup 1}H-MRS (choline concentration relative to water [Cho/W]), DCE-MRI (volume transfer constant [K{sup trans}]; volume fraction of the extravascular extracellular space [v{sub e}]; and redistribution rate constant [k{sub ep}]), and [{sup 18}F]FDG PET (standard uptake value [SUV] and total lesion glycolysis [TLG]) were calculated using nonparametric Spearman rank correlation. To predict short-term responses, logistic regression analysis was performed. Results: A significant positive correlation was found between Cho/W and TLG ({rho} = 0.599; p = 0.031). Cho/W correlated negatively with heterogeneity measures of standard deviation std(v{sub e}) ({rho} = -0.691; p = 0.004) and std(k{sub ep}) ({rho} = -0.704; p = 0.003). Maximum SUV (SUVmax) values correlated strongly with MRI tumor volume ({rho} = 0.643; p = 0.007). Logistic regression indicated that std(K{sup trans}) and SUVmean were significant predictors of short-term response (p < 0.07). Conclusion: Pretreatment multimodality imaging using {sup 1}H-MRS, DCE-MRI, and [{sup 18}F]FDG PET is feasible in HNSCC patients with nodal metastases. Additionally, combined DCE-MRI and [{sup 18}F]FDG PET parameters were predictive of short-term response to treatment.

  17. Genetically engineered sensors for non-invasive molecular imaging using MRI

    E-Print Network [OSTI]

    Shapiro, Mikhail G

    2008-01-01

    Technologies that provide information about the concentrations or activities of specific molecules in living subjects have the potential to greatly advance science and medicine. Magnetic resonance imaging (MRI) is a tool ...

  18. Engineering genetically-encodable MRI contrast agents for in vivo imaging

    E-Print Network [OSTI]

    Matsumoto, Yuri, Ph. D. Massachusetts Institute of Technology

    2014-01-01

    Magnetic resonance imaging (MRI) is gaining recognition as a powerful tool in biological research, offering non-invasive access to anatomy and activity at high spatial and temporal resolution. However, the range of biological ...

  19. The Future of Real-time Cardiac Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Southern California, University of

    Address *Electrical Engineering-Systems, 3740 McClintock Avenue, EEB 406, University of Southern. These and other factors require real-time imaging. Magnetic resonance imaging (MRI) is a powerful and flexible with excellent image quality. In this article, the term real-time refers to imaging sys- tems that acquire

  20. K-space reconstruction of magnetic resonance inverse imaging (K-InI) of human visuomotor systems

    E-Print Network [OSTI]

    MRI InI Visual MRI Neuroimaging K-InI Inverse solution MEG EEG Electroencephalography channels of a radio-frequency coil array, magnetic resonance inverse imaging (InI) can achieve ultra. Mathematically, the InI reconstruction is a generalization of parallel MRI (pMRI), which includes image space

  1. A 64-channel personal computer based image reconstruction system and applications in single echo acquisition magnetic resonance elastography and ultra-fast magnetic resonance imaging

    E-Print Network [OSTI]

    Yallapragada, Naresh

    2009-05-15

    Emerging technologies in parallel magnetic resonance imaging (MRI) with massive receiver arrays have paved the way for ultra-fast imaging at increasingly high frame rates. With the increase in the number of receiver channels ...

  2. MRI Magnet Design: Search Space Analysis, EDAs and a Real-World Problem with Significant Dependencies

    E-Print Network [OSTI]

    Gallagher, Marcus

    of superconductive magnet configurations in Magnetic Resonance Imaging (MRI) systems as a challenging real

  3. Bayesian Optimization of Magnetic Resonance Imaging Sequences

    E-Print Network [OSTI]

    Seeger, Matthias

    Imaging 2 Bayesian Experimental Design 3 Scalable Approximate Inference 4 Experiments Seeger (MMCI Healthcare: Growing number of MRI diagnoses Brain research: Ethical human subject studies Seeger (MMCI Extremely versatile Noninvasive, no ionizing radiation Seeger (MMCI) Bayesian MRI Optimization 28 November

  4. Chromatic Light Adaptation Measured using Functional Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Wandell, Brian A.

    Chromatic Light Adaptation Measured using Functional Magnetic Resonance Imaging Alex R. Wade- nisms within cone photoreceptor classes. Key words: fMRI; light adaptation; cones; simulation; V1; Naka regulation is part of a process called light adaptation. Light adaptation is an important computational step

  5. Modeling Left Ventricle Wall Motion Using Tagged Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Alenezy, Mohammed D.

    2009-04-17

    A two-parameter computational model is proposed for the study of the regional motion of the left ventricle (LV) wall using tagged magnetic resonance imaging (tMRI) data. In this model, the LV wall motion is mathematically decomposed into two...

  6. Original Research In Vivo Magnetic Resonance Imaging of the Human

    E-Print Network [OSTI]

    Gorassini, Monica

    Original Research In Vivo Magnetic Resonance Imaging of the Human Cervical Spinal Cord at 3 Tesla is feasible at 3 T. Key Words: MRI; 3 Tesla; cervical spinal cord; gradient echo; gray matter; white matter J, and pulsatile flow (9,10). Deficits in motor and sensory function from damage to the spinal cord are mainly due

  7. A pulsed electromagnet controller for prepolarized MRI 

    E-Print Network [OSTI]

    Nam, Hyokwon

    2001-01-01

    Magnetic resonance imaging (MRI) is a popular medical imaging modality that provides high resolution images with superior contrast. Conventional MRI systems rely on large magnets to generate the main magnetic field, B?, that is both strong...

  8. An iterative technique for refinement of selective excitations for magnetic resonance imaging 

    E-Print Network [OSTI]

    Lebsack, Eliot Todd

    1999-01-01

    Selective RF pulses are needed or many application in magnetic resonance imaging (MRI). The desired excitation profile is omen used as the spectrum of the applied RF pulse; the modulation waveform of the RF pulse which approximately excites...

  9. Transmit field pattern control for high field magnetic resonance imaging with integrated RF current sources 

    E-Print Network [OSTI]

    Kurpad, Krishna Nagaraj

    2005-11-01

    The primary design criterion for RF transmit coils for MRI is uniform transverse magnetic (B1) field. Currently, most high frequency transmit coils are designed as periodic, symmetric structures that are resonant at the imaging frequency...

  10. Multimodal neuroimaging with simultaneous electroencephalogram and high-field functional magnetic resonance imaging

    E-Print Network [OSTI]

    Purdon, Patrick L. (Patrick Lee), 1974-

    2005-01-01

    Simultaneous recording of electroencephalogram (EEG) and functional magnetic resonance imaging (tMRI) is an important emerging tool in functional neuroimaging with the potential to reveal new mechanisms for brain function ...

  11. Semi-automatic delineation using weighted CT-MRI registered images for radiotherapy of nasopharyngeal cancer

    SciTech Connect (OSTI)

    Fitton, I. [European Georges Pompidou Hospital, Department of Radiology, 20 rue Leblanc, 75015, Paris (France); Cornelissen, S. A. P. [Image Sciences Institute, UMC, Department of Radiology, P.O. Box 85500, 3508 GA Utrecht (Netherlands); Duppen, J. C.; Rasch, C. R. N.; Herk, M. van [The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Department of Radiotherapy, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Steenbakkers, R. J. H. M. [University Medical Center Groningen, Department of Radiation Oncology, Hanzeplein 1, 9713 GZ Groningen (Netherlands); Peeters, S. T. H. [UZ Gasthuisberg, Herestraat 49, 3000 Leuven, Belgique (Belgium); Hoebers, F. J. P. [Maastricht University Medical Center, Department of Radiation Oncology (MAASTRO clinic), GROW School for Oncology and Development Biology Maastricht, 6229 ET Maastricht (Netherlands); Kaanders, J. H. A. M. [UMC St-Radboud, Department of Radiotherapy, Geert Grooteplein 32, 6525 GA Nijmegen (Netherlands); Nowak, P. J. C. M. [ERASMUS University Medical Center, Department of Radiation Oncology,Groene Hilledijk 301, 3075 EA Rotterdam (Netherlands)

    2011-08-15

    Purpose: To develop a delineation tool that refines physician-drawn contours of the gross tumor volume (GTV) in nasopharynx cancer, using combined pixel value information from x-ray computed tomography (CT) and magnetic resonance imaging (MRI) during delineation. Methods: Operator-guided delineation assisted by a so-called ''snake'' algorithm was applied on weighted CT-MRI registered images. The physician delineates a rough tumor contour that is continuously adjusted by the snake algorithm using the underlying image characteristics. The algorithm was evaluated on five nasopharyngeal cancer patients. Different linear weightings CT and MRI were tested as input for the snake algorithm and compared according to contrast and tumor to noise ratio (TNR). The semi-automatic delineation was compared with manual contouring by seven experienced radiation oncologists. Results: A good compromise for TNR and contrast was obtained by weighing CT twice as strong as MRI. The new algorithm did not notably reduce interobserver variability, it did however, reduce the average delineation time by 6 min per case. Conclusions: The authors developed a user-driven tool for delineation and correction based a snake algorithm and registered weighted CT image and MRI. The algorithm adds morphological information from CT during the delineation on MRI and accelerates the delineation task.

  12. Can Images Obtained With High Field Strength Magnetic Resonance Imaging Reduce Contouring Variability of the Prostate?

    SciTech Connect (OSTI)

    Usmani, Nawaid, E-mail: Nawaid.Usmani@albertahealthservices.ca [Department of Radiation Oncology, Cross Cancer Institute, Edmonton, AB (Canada); Department of Oncology, University of Alberta, Edmonton, AB (Canada); Sloboda, Ron [Department of Oncology, University of Alberta, Edmonton, AB (Canada); Department of Medical Physics, Cross Cancer Institute, Edmonton, AB (Canada); Kamal, Wafa [Department of Radiation Oncology, Cross Cancer Institute, Edmonton, AB (Canada); Ghosh, Sunita [Department of Oncology, University of Alberta, Edmonton, AB (Canada); Department of Experimental Oncology, Cross Cancer Institute, Edmonton, AB (Canada); Pervez, Nadeem; Pedersen, John; Yee, Don; Danielson, Brita; Murtha, Albert; Amanie, John [Department of Radiation Oncology, Cross Cancer Institute, Edmonton, AB (Canada); Department of Oncology, University of Alberta, Edmonton, AB (Canada); Monajemi, Tara [Department of Medical Physics, Cross Cancer Institute, Edmonton, AB (Canada)

    2011-07-01

    Purpose: The objective of this study is to determine whether there is less contouring variability of the prostate using higher-strength magnetic resonance images (MRI) compared with standard MRI and computed tomography (CT). Methods and Materials: Forty patients treated with prostate brachytherapy were accrued to a prospective study that included the acquisition of 1.5-T MR and CT images at specified time points. A subset of 10 patients had additional 3.0-T MR images acquired at the same time as their 1.5-T MR scans. Images from each of these patients were contoured by 5 radiation oncologists, with a random subset of patients repeated to quantify intraobserver contouring variability. To minimize bias in contouring the prostate, the image sets were placed in folders in a random order with all identifiers removed from the images. Results: Although there was less interobserver contouring variability in the overall prostate volumes in 1.5-T MRI compared with 3.0-T MRI (p < 0.01), there was no significant differences in contouring variability in the different regions of the prostate between 1.5-T MRI and 3.0-T MRI. MRI demonstrated significantly less interobserver contouring variability in both 1.5-T and 3.0-T compared with CT in overall prostate volumes (p < 0.01, p = 0.01), with the greatest benefits being appreciated in the base of the prostate. Overall, there was less intraobserver contouring variability than interobserver contouring variability for all of the measurements analyzed. Conclusions: Use of 3.0-T MRI does not demonstrate a significant improvement in contouring variability compared with 1.5-T MRI, although both magnetic strengths demonstrated less contouring variability compared with CT.

  13. A 64 Channel Transmit System for Single Echo Acquisition MRI 

    E-Print Network [OSTI]

    Feng, Ke

    2012-10-19

    Magnetic Resonance Imaging (MRI) is considered as a slow imaging technique. Various approaches to accelerate MRI imaging have been explored by researchers in the past decades. Earlier gradient based methods have reached the safety limit. Parallel...

  14. Portable low-cost magnetic resonance imaging

    E-Print Network [OSTI]

    Cooley, Clarissa Zimmerman

    2014-01-01

    Purpose: As the premiere modality for brain imaging, MRI could find wider applicability if lightweight, portable systems were available for siting in unconventional locations such as intensive care units (ICUs), physician ...

  15. A cryogen-free ultralow-field superconducting quantum interference device magnetic resonance imaging system

    SciTech Connect (OSTI)

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob, E-mail: ihahn@caltech.edu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

    2014-09-15

    Magnetic resonance imaging (MRI) at microtesla fields using superconducting quantum interference device (SQUID) detection has previously been demonstrated, and advantages have been noted. Although the ultralow-field SQUID MRI technique would not need the heavy superconducting magnet of conventional MRI systems, liquid helium required to cool the low-temperature detector still places a significant burden on its operation. We have built a prototype cryocooler-based SQUID MRI system that does not require a cryogen. The SQUID detector and the superconducting gradiometer were cooled down to 3.7 K and 4.3 K, respectively. We describe the prototype design, characterization, a phantom image, and areas of further improvements needed to bring the imaging performance to parity with conventional MRI systems.

  16. Nuclear magnetic resonance imaging with hyper-polarized noble gases

    SciTech Connect (OSTI)

    Schmidt, D.M.; George, J.S.; Penttila, S.I.; Caprihan, A.

    1997-10-01

    This is the final report of a six-month, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The nuclei of noble gases can be hyper polarized through a laser-driven spin exchange to a degree many orders of magnitude larger than that attainable by thermal polarization without requiring a strong magnetic field. The increased polarization from the laser pumping enables a good nuclear magnetic resonance (NMR) signal from a gas. The main goal of this project was to demonstrate diffusion-weighted imaging of such hyper-polarized noble gas with magnetic resonance imaging (MRI). Possible applications include characterizing porosity of materials and dynamically imaging pressure distributions in biological or acoustical systems.

  17. Gradient characterization in magnetic resonance imaging

    E-Print Network [OSTI]

    Cheng, Joseph Yitan

    2007-01-01

    Special magnetic resonance (MR) scans, such as spiral imaging and echo-planar imaging, require speed and gradient accuracy while putting high demands on the MR gradient system that may cause gradient distortion. Additionally, ...

  18. Advanced MRI image reconstruction methods Jeffrey A. Fessler

    E-Print Network [OSTI]

    Fessler, Jeffrey A.

    1 Advanced MRI image reconstruction methods Jeffrey A. Fessler EECS Department BME Department, Dept in solution · 2003. Nobel prize in medicine to P. Lauterbur and Sir P. Mansfield! · 2005. Lustig, Donoho M0(rrr) spin (Hydrogen) density · Longitudinal (spin-lattice) relaxation T1(rrr) · Transverse (spin

  19. Imaging agents for in vivo magnetic resonance and scintigraphic imaging

    DOE Patents [OSTI]

    Engelstad, B.L.; Raymond, K.N.; Huberty, J.P.; White, D.L.

    1991-04-23

    Methods are provided for in vivo magnetic resonance imaging and/or scintigraphic imaging of a subject using chelated transition metal and lanthanide metal complexes. Novel ligands for these complexes are provided. No Drawings

  20. Event-related single-shot volumetric functional magnetic resonance inverse imaging of visual processing

    E-Print Network [OSTI]

    Event-related single-shot volumetric functional magnetic resonance inverse imaging of visual head coil array data and then apply inverse reconstruction methods to obtain volumetric fMRI estimates-related brain activity. We demonstrate the sensitivity and inter-subject reliability of volumetric InI using

  1. Instruments High-resolution imaging of

    E-Print Network [OSTI]

    Boppart, Stephen

    Instruments & Methods High-resolution imaging of gynecologic neoplasms using optical coherence and Gynecologists.) Diagnostic imaging methods available to gynecologists include magnetic resonance imaging (MRI

  2. Design of an MRI compatible robot for wrist rehabilitation

    E-Print Network [OSTI]

    Mendelowitz, Sarah E. (Sarah Elizabeth), 1980-

    2005-01-01

    Magnetic Resonance Imaging (MRI) can be used to study the effects of robotic therapy on stroke patients. This thesis focuses on the design of an MRI compatible wrist robot to be used as a clinical tool for studying the ...

  3. Flow Imaging Using MRI: Quantification and Analysis 

    E-Print Network [OSTI]

    Jiraraksopakun, Yuttapong

    2010-07-14

    ) orthogonal one-dimensional displacement from all tag detected points [51]. Most of these motion analyses has been developed extensively to visualize or to assess cardiac motion. In analysis of heart motion, the myocardial contours at left ventricle (LV... and to automatically track both in-plane and through-plane displacements in three dimensions from a single image plane using a modified SF-CSPAMM [88]. Based on thin slice thickness and phase invariance conditions, the method (zHARP) can directly track the three-dimensional...

  4. Array combination for parallel imaging in Magnetic Resonance Imaging 

    E-Print Network [OSTI]

    Spence, Dan Kenrick

    2007-09-17

    In Magnetic Resonance Imaging, the time required to generate an image is proportional to the number of steps used to encode the spatial information. In rapid imaging, an array of coil elements and receivers are used to reduce the number of encoding...

  5. Semi-automatic delineation using weighted CT-MRI registered images...

    Office of Scientific and Technical Information (OSTI)

    delineation using weighted CT-MRI registered images for radiotherapy of nasopharyngeal cancer Citation Details In-Document Search Title: Semi-automatic delineation using weighted...

  6. Method and apparatus for magnetic resonance imaging and spectroscopy using microstrip transmission line coils

    DOE Patents [OSTI]

    Zhang, Xiaoliang; Ugurbil, Kamil; Chen, Wei

    2006-04-04

    Apparatus and method for MRI imaging using a coil constructed of microstrip transmission line (MTL coil) are disclosed. In one method, a target is positioned to be imaged within the field of a main magnetic field of a magnet resonance imaging (MRI) system, a MTL coil is positioned proximate the target, and a MRI image is obtained using the main magnet and the MTL coil. In another embodiment, the MRI coil is used for spectroscopy. MRI imaging and spectroscopy coils are formed using microstrip transmission line. These MTL coils have the advantageous property of good performance while occupying a relatively small space, thus allowing MTL coils to be used inside restricted areas more easily than some other prior art coils. In addition, the MTL coils are relatively simple to construct of inexpensive components and thus relatively inexpensive compared to other designs. Further, the MTL coils of the present invention can be readily formed in a wide variety of coil configurations, and used in a wide variety of ways. Further, while the MTL coils of the present invention work well at high field strengths and frequencies, they also work at low frequencies and in low field strengths as well.

  7. Challenges for molecular neuroimaging with MRI

    E-Print Network [OSTI]

    Lelyveld, Victor S.

    Magnetic resonance (MRI)-based molecular imaging methods are beginning to have impact in neuroscience. A growing number of molecular imaging agents have been synthesized and tested in vitro, but so far relatively few have ...

  8. Magnetic resonance imaging of living systems by remote detection

    DOE Patents [OSTI]

    Wemmer, David; Pines, Alexander; Bouchard, Louis; Xu, Shoujun; Harel, Elad; Budker, Dmitry; Lowery, Thomas; Ledbetter, Micah

    2013-10-29

    A novel approach to magnetic resonance imaging is disclosed. Blood flowing through a living system is prepolarized, and then encoded. The polarization can be achieved using permanent or superconducting magnets. The polarization may be carried out upstream of the region to be encoded or at the place of encoding. In the case of an MRI of a brain, polarization of flowing blood can be effected by placing a magnet over a section of the body such as the heart upstream of the head. Alternatively, polarization and encoding can be effected at the same location. Detection occurs at a remote location, using a separate detection device such as an optical atomic magnetometer, or an inductive Faraday coil. The detector may be placed on the surface of the skin next to a blood vessel such as a jugular vein carrying blood away from the encoded region.

  9. Next Generation Magnetic Resonance Imaging Contrast Agents

    E-Print Network [OSTI]

    Klemm, Piper Julia

    2012-01-01

    Meade, T. J. Gd(III)-Nanodiamond conjugates for MRI contrastMeade, T. J. Gd(III)-Nanodiamond conjugates for MRI contrastMeade, T. J. Gd(III)-Nanodiamond conjugates for MRI contrast

  10. Suppressing Multi-Channel Ultra-Low-Field MRI Measurement Noise Using Data Consistency and Image

    E-Print Network [OSTI]

    Suppressing Multi-Channel Ultra-Low-Field MRI Measurement Noise Using Data Consistency and Image of Mathematics, National Taiwan University, Taipei, Taiwan, 4 Elekta Oy, Helsinki, Finland Abstract Ultra-low. (2013) Suppressing Multi-Channel Ultra-Low-Field MRI Measurement Noise Using Data Consistency and Image

  11. fMRI Brain Image Retrieval Based on ICA Components bbai@cs.rutgers.edu

    E-Print Network [OSTI]

    fMRI Brain Image Retrieval Based on ICA Components Bing Bai bbai@cs.rutgers.edu Department This manuscript proposes a retrieval system for fMRI brain images. Our goal is to find a similarity- metric to enable us to support queries for "similar tasks" for retrieval on a large collection of brain ex

  12. In vivo chlorine-35, sodium-23 and proton magnetic resonance imaging of the rat brain , M. Augath2

    E-Print Network [OSTI]

    In vivo chlorine-35, sodium-23 and proton magnetic resonance imaging of the rat brain S. Kirsch1 of the cytoplasm and the volume of cells [1]. In order to investigate the feasibility of combined in vivo 35 Cl, 23 Na and 1 H MRI we developed a rf coil setup to measure 35 Cl, 23 Na and 1 H signals in one scanning

  13. Neurobiology of Aging xxx (2006) xxxxxx Structural MRI covariance patterns associated with normal

    E-Print Network [OSTI]

    2006-01-01

    .1) participants were scanned with a 1.5 T MRI machine and assessed with a cognitive battery. Images were spatially 2005 Abstract Structural magnetic resonance imaging (MRI) studies have shown dramatic age magnetic resonance images allow for between- and within-groups comparison of grey and white matter volume

  14. Classification System for Identifying Women at Risk for Altered Partial Breast Irradiation Recommendations After Breast Magnetic Resonance Imaging

    SciTech Connect (OSTI)

    Kowalchik, Kristin V.; Vallow, Laura A.; McDonough, Michelle; Thomas, Colleen S.; Heckman, Michael G.; Peterson, Jennifer L.; Adkisson, Cameron D.; Serago, Christopher; McLaughlin, Sarah A.

    2013-09-01

    Purpose: To study the utility of preoperative breast MRI for partial breast irradiation (PBI) patient selection, using multivariable analysis of significant risk factors to create a classification rule. Methods and Materials: Between 2002 and 2009, 712 women with newly diagnosed breast cancer underwent preoperative bilateral breast MRI at Mayo Clinic Florida. Of this cohort, 566 were retrospectively deemed eligible for PBI according to the National Surgical Adjuvant Breast and Bowel Project Protocol B-39 inclusion criteria using physical examination, mammogram, and/or ultrasound. Magnetic resonance images were then reviewed to determine their impact on patient eligibility. The patient and tumor characteristics were evaluated to determine risk factors for altered PBI eligibility after MRI and to create a classification rule. Results: Of the 566 patients initially eligible for PBI, 141 (25%) were found ineligible because of pathologically proven MRI findings. Magnetic resonance imaging detected additional ipsilateral breast cancer in 118 (21%). Of these, 62 (11%) had more extensive disease than originally noted before MRI, and 64 (11%) had multicentric disease. Contralateral breast cancer was detected in 28 (5%). Four characteristics were found to be significantly associated with PBI ineligibility after MRI on multivariable analysis: premenopausal status (P=.021), detection by palpation (P<.001), first-degree relative with a history of breast cancer (P=.033), and lobular histology (P=.002). Risk factors were assigned a score of 0-2. The risk of altered PBI eligibility from MRI based on number of risk factors was 0:18%; 1:22%; 2:42%; 3:65%. Conclusions: Preoperative bilateral breast MRI altered the PBI recommendations for 25% of women. Women who may undergo PBI should be considered for breast MRI, especially those with lobular histology or with 2 or more of the following risk factors: premenopausal, detection by palpation, and first-degree relative with a history of breast cancer.

  15. Segmentation of Spin-Echo MRI brain images: a comparison study of Crisp and Fuzzy algorithms 

    E-Print Network [OSTI]

    Chung, Maranatha

    1993-01-01

    This thesis presents a scheme for segmenting Spin-Echo MRI brain images based on Fuzzy C-Mean (FCM) clustering techniques. This scheme consists of feature extraction, feature conditioning or evaluation, and thresholded FCM clustering. Feature...

  16. Analysis of Lanthanide Complex Dendrimer Conjugates for Bimodal NIR and MRI Imaging

    E-Print Network [OSTI]

    Andolina, Christopher

    2014-01-01

    Conjugates for Bimodal NIR and MRI Imaging Authors:into a TAC Start signal (NIM) using a TB-01 pulse converterappropriate TAC Stop signals (NIM). Signals from the visible

  17. MRI Magnetic Signature Imaging, Tracking and Navigation for Targeted Micro/Nano-capsule Therapeutics

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    - back for the microdevice and a propulsion sequence to enable interleaved magnetic propulsionMRI Magnetic Signature Imaging, Tracking and Navigation for Targeted Micro J. Nelson, Antoine Ferreira and Sergej Fatikow Abstract-- The propulsion of nano

  18. Methods for functional brain imaging

    E-Print Network [OSTI]

    Witzel, Thomas, Ph. D. Massachusetts Institute of Technology

    2011-01-01

    Magnetic resonance imaging (MRI) has demonstrated the potential for non-invasive mapping of structure and function (fMRI) in the human brain. In this thesis, we propose a series of methodological developments towards ...

  19. Evaluation of the Prostate Bed for Local Recurrence After Radical Prostatectomy Using Endorectal Magnetic Resonance Imaging

    SciTech Connect (OSTI)

    Liauw, Stanley L., E-mail: sliauw@radonc.uchicago.edu [Department of Radiation Oncology, University of Chicago, Chicago, Illinois (United States); Pitroda, Sean P. [Department of Radiation Oncology, University of Chicago, Chicago, Illinois (United States)] [Department of Radiation Oncology, University of Chicago, Chicago, Illinois (United States); Eggener, Scott E. [Department of Urology, University of Chicago, Chicago, Illinois (United States)] [Department of Urology, University of Chicago, Chicago, Illinois (United States); Stadler, Walter M. [Department of Medical Oncology, University of Chicago, Chicago, Illinois (United States)] [Department of Medical Oncology, University of Chicago, Chicago, Illinois (United States); Pelizzari, Charles A. [Department of Radiation Oncology, University of Chicago, Chicago, Illinois (United States)] [Department of Radiation Oncology, University of Chicago, Chicago, Illinois (United States); Vannier, Michael W.; Oto, Aytek [Department of Radiology, University of Chicago, Chicago, Illinois (United States)] [Department of Radiology, University of Chicago, Chicago, Illinois (United States)

    2013-02-01

    Purpose: To summarize the results of a 4-year period in which endorectal magnetic resonance imaging (MRI) was considered for all men referred for salvage radiation therapy (RT) at a single academic center; to describe the incidence and location of locally recurrent disease in a contemporary cohort of men with biochemical failure after radical prostatectomy (RP), and to identify prognostic variables associated with MRI findings in order to define which patients may have the highest yield of the study. Methods and Materials: Between 2007 and 2011, 88 men without clinically palpable disease underwent eMRI for detectable prostate-specific antigen (PSA) after RP. The median interval between RP and eMRI was 32 months (interquartile range, 14-57 months), and the median PSA level was 0.30 ng/mL (interquartile range, 0.19-0.72 ng/mL). Magnetic resonance imaging scans consisting of T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging were evaluated for features consistent with local recurrence. The prostate bed was scored from 0-4, whereby 0 was definitely normal, 1 probably normal, 2 indeterminate, 3 probably abnormal, and 4 definitely abnormal. Local recurrence was defined as having a score of 3-4. Results: Local recurrence was identified in 21 men (24%). Abnormalities were best appreciated on T2-weighted axial images (90%) as focal hypointense lesions. Recurrence locations were perianastomotic (67%) or retrovesical (33%). The only risk factor associated with local recurrence was PSA; recurrence was seen in 37% of men with PSA >0.3 ng/mL vs 13% if PSA {<=}0.3 ng/mL (P<.01). The median volume of recurrence was 0.26 cm{sup 3} and was directly associated with PSA (r=0.5, P=.02). The correlation between MRI-based tumor volume and PSA was even stronger in men with positive margins (r=0.8, P<.01). Conclusions: Endorectal MRI can define areas of local recurrence after RP in a minority of men without clinical evidence of disease, with yield related to PSA. Further study is necessary to determine whether eMRI can improve patient selection and success of salvage RT.

  20. Direct imaging of neural currents using ultra-low field magnetic resonance techniques

    DOE Patents [OSTI]

    Volegov, Petr L. (Los Alamos, NM); Matlashov, Andrei N. (Los Alamos, NM); Mosher, John C. (Los Alamos, NM); Espy, Michelle A. (Los Alamos, NM); Kraus, Jr., Robert H. (Los Alamos, NM)

    2009-08-11

    Using resonant interactions to directly and tomographically image neural activity in the human brain using magnetic resonance imaging (MRI) techniques at ultra-low field (ULF), the present inventors have established an approach that is sensitive to magnetic field distributions local to the spin population in cortex at the Larmor frequency of the measurement field. Because the Larmor frequency can be readily manipulated (through varying B.sub.m), one can also envision using ULF-DNI to image the frequency distribution of the local fields in cortex. Such information, taken together with simultaneous acquisition of MEG and ULF-NMR signals, enables non-invasive exploration of the correlation between local fields induced by neural activity in cortex and more `distant` measures of brain activity such as MEG and EEG.

  1. Functional Magnetic Resonance Imaging of Motor Cortex Activation in Schizophrenia

    E-Print Network [OSTI]

    2015-01-01

    Magnetic Resonance Imaging of Motor Cortex Activation inBrain dysfunction during motor activation and corpus callo-Lee HJ, et al. • FMRI of Motor Cortex Activation in

  2. Magnetic resonance imaging of self-assembled biomaterial scaffolds

    DOE Patents [OSTI]

    Bull, Steve R; Meade, Thomas J; Stupp, Samuel I

    2014-09-16

    Compositions and/or mixtures comprising peptide amphiphile compounds comprising one or more contrast agents, as can be used in a range of magnetic resonance imaging applications.

  3. Applications of MRI in Fluidics: Single Echo Acquisition MRI Toward Microfluidics 

    E-Print Network [OSTI]

    Bosshard, John

    2006-08-16

    resonance imaging (MRI) to microscale fluid flow quantification. This is important because development and improvement of microfluidic devices requires the ability to accurately and non-invasively measure microscale flow. Lab-on-a-chip aims to integrate...

  4. Nanoscale magnetic resonance imaging C. L. Degena

    E-Print Network [OSTI]

    Leonardo, Degiorgi

    tobacco mosaic virus particles sitting on a nanometer-thick layer of ad- sorbed hydrocarbons. This result, which represents a 100 million- fold improvement in volume resolution over conventional MRI considerable effort, attempts to push the spatial resolution of conventional MRI into the realm of high

  5. Magnetic resonance spectroscopic imaging using parallel transmission at 7T

    E-Print Network [OSTI]

    Gagoski, Borjan Aleksandar

    2011-01-01

    Conventional magnetic resonance spectroscopic imaging (MRSI), also known as phase-encoded (PE) chemical shift imaging (CSI), suffers from both low signal-to-noise ratio (SNR) of the brain metabolites, as well as inflexible ...

  6. Posture-Dependent Human 3He Lung Imaging in an Open Access MRI System: Initial Results

    E-Print Network [OSTI]

    Tsai, L L; Li, C -H; Rosen, M S; Patz, S; Walsworth, R L

    2007-01-01

    The human lung and its functions are extremely sensitive to orientation and posture, and debate continues as to the role of gravity and the surrounding anatomy in determining lung function and heterogeneity of perfusion and ventilation. However, study of these effects is difficult. The conventional high-field magnets used for most hyperpolarized 3He MRI of the human lung, and most other common radiological imaging modalities including PET and CT, restrict subjects to lying horizontally, minimizing most gravitational effects. In this paper, we briefly review the motivation for posture-dependent studies of human lung function, and present initial imaging results of human lungs in the supine and vertical body orientations using inhaled hyperpolarized 3He gas and an open-access MRI instrument. The open geometry of this MRI system features a "walk-in" capability that permits subjects to be imaged in vertical and horizontal positions, and potentially allows for complete rotation of the orientation of the imaging su...

  7. MAGNETIC RESONANCE IMAGE VIEWING ``SCREEN REAL ESTATE'' PROBLEM

    E-Print Network [OSTI]

    Atkins, M. Stella

    MAGNETIC RESONANCE IMAGE VIEWING AND THE ``SCREEN REAL ESTATE'' PROBLEM By Johanna van der Heyden B Degree: Master of Science Title of thesis: Magnetic Resonance Image Viewing and the ``Screen Real Estate. These ``screen real estate'' issues are extensively explored in the literature but not consistently applied

  8. A Spectral-Scanning Magnetic Resonance Imaging (MRI) Integrated System

    E-Print Network [OSTI]

    Hajimiri, Ali

    , detection time, spectral resolution, and the spatial resolution (relative to the sample size) equivalent that the electromotive force (emf) voltage induced in the coils of the MR system, )(tE , is describe by [ ] -= V n d

  9. A Prospective Study of the Utility of Magnetic Resonance Imaging in Determining Candidacy for Partial Breast Irradiation

    SciTech Connect (OSTI)

    Dorn, Paige L.; Al-Hallaq, Hania A.; Haq, Farah; Goldberg, Mira; Abe, Hiroyuki; Hasan, Yasmin; Chmura, Steven J.

    2013-03-01

    Purpose: Retrospective data have demonstrated that breast magnetic resonance imaging (MRI) may change a patient's eligibility for partial breast irradiation (PBI) by identifying multicentric, multifocal, or contralateral disease. The objective of the current study was to prospectively determine the frequency with which MRI identifies occult disease and to establish clinical factors associated with a higher likelihood of MRI prompting changes in PBI eligibility. Methods and Materials: At The University of Chicago, women with breast cancer uniformly undergo MRI in addition to mammography and ultrasonography. From June 2009 through May 2011, all patients were screened prospectively in a multidisciplinary conference for PBI eligibility based on standard imaging, and the impact of MRI on PBI eligibility according to National Surgical Adjuvant Breast and Bowel Project protocol B-39/Radiation Therapy Oncology Group protocol 0413 entry criteria was recorded. Univariable analysis was performed using clinical characteristics in both the prospective cohort and in a separate cohort of retrospectively identified patients. Pooled analysis was used to derive a scoring index predictive of the risk that MRI would identify additional disease. Results: A total of 521 patients were screened for PBI eligibility, and 124 (23.8%) patients were deemed eligible for PBI based on standard imaging. MRI findings changed PBI eligibility in 12.9% of patients. In the pooled univariable analysis, tumor size ?2 cm on mammography or ultrasonography (P=.02), age <50 years (P=.01), invasive lobular histology (P=.01), and HER-2/neu amplification (P=.01) were associated with a higher likelihood of MRI changing PBI eligibility. A predictive score was generated by summing the number of significant risk factors. Patients with a score of 0, 1, 2, and 3 had changes to eligibility based on MRI findings in 2.8%, 13.2%, 38.1%, and 100%, respectively (P<.0001). Conclusions: MRI identified additional disease in a significant number of patients eligible for PBI, based on standard imaging. Clinical characteristics may be useful in directing implementation of MRI in the staging of PBI candidates.

  10. Minimally Invasive Magnetic Resonance Imaging-Guided Free-Hand Aspiration of Symptomatic Nerve Route Compressing Lumbosacral Cysts Using a 1.0-Tesla Open Magnetic Resonance Imaging System

    SciTech Connect (OSTI)

    Bucourt, Maximilian de, E-mail: mdb@charite.de; Streitparth, Florian, E-mail: florian.streitparth@charite.de; Collettini, Federico [Charite-University Medicine, Department of Radiology (Germany); Guettler, Felix [Jena University, Department of Radiology (Germany); Rathke, Hendrik; Lorenz, Britta; Rump, Jens; Hamm, Bernd [Charite-University Medicine, Department of Radiology (Germany); Teichgraeber, U. K. [Jena University, Department of Radiology (Germany)

    2012-02-15

    Purpose: To evaluate the feasibility of minimally invasive magnetic resonance imaging (MRI)-guided free-hand aspiration of symptomatic nerve route compressing lumbosacral cysts in a 1.0-Tesla (T) open MRI system using a tailored interactive sequence. Materials and Methods: Eleven patients with MRI-evident symptomatic cysts in the lumbosacral region and possible nerve route compressing character were referred to a 1.0-T open MRI system. For MRI interventional cyst aspiration, an interactive sequence was used, allowing for near real-time position validation of the needle in any desired three-dimensional plane. Results: Seven of 11 cysts in the lumbosacral region were successfully aspirated (average 10.1 mm [SD {+-} 1.9]). After successful cyst aspiration, each patient reported speedy relief of initial symptoms. Average cyst size was 9.6 mm ({+-}2.6 mm). Four cysts (8.8 {+-} 3.8 mm) could not be aspirated. Conclusion: Open MRI systems with tailored interactive sequences have great potential for cyst aspiration in the lumbosacral region. The authors perceive major advantages of the MR-guided cyst aspiration in its minimally invasive character compared to direct and open surgical options along with consecutive less trauma, less stress, and also less side-effects for the patient.

  11. Repeated exposure of the developing rat brain to magnetic resonance imaging did not affect neurogenesis, cell death or memory function

    SciTech Connect (OSTI)

    Zhu, Changlian [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden) [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden); Department of Pediatrics, The Third Affiliated Hospital, Zhengzhou University (China); Gao, Jianfeng [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden) [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden); Department of Pediatrics, The Third Affiliated Hospital, Zhengzhou University (China); Department of Physiology, Henan Traditional Medical University (China); Li, Qian; Huang, Zhiheng; Zhang, Yu; Li, Hongfu [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden) [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden); Department of Pediatrics, The Third Affiliated Hospital, Zhengzhou University (China); Kuhn, Hans-Georg [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden)] [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden); Blomgren, Klas, E-mail: klas.blomgren@neuro.gu.se [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden) [Center for Brain Repair and Rehabilitation, University of Gothenburg (Sweden); Department of Pediatric Oncology, The Queen Silvia Children's Hospital, Gothenburg (Sweden)

    2011-01-07

    Research highlights: {yields} The effect of MRI on the developing brain is a matter of debate. {yields} Repeated exposure to MRI did not affect neurogenesis. {yields} Memory function was not affected by repeated MRI during development. {yields} Neither late gestation nor young postnatal brains were affected by MRI. {yields} Repeated MRI did not cause cell death in the neurogenic region of the hippocampus. -- Abstract: The effect of magnetic fields on the brain is a matter of debate. The objective of this study was to investigate whether repeated exposure to strong magnetic fields, such as during magnetic resonance imaging (MRI), could elicit changes in the developing rat brain. Embryonic day 15 (E15) and postnatal day 14 (P14) rats were exposed to MRI using a 7.05 T MR system. The animals were anesthetized and exposed for 35 min per day for 4 successive days. Control animals were anesthetized but no MRI was performed. Body temperature was maintained at 37 {sup o}C. BrdU was injected after each session (50 mg/kg). One month later, cell proliferation, neurogenesis and astrogenesis in the dentate gyrus were evaluated, revealing no effects of MRI, neither in the E15, nor in the P14 group. DNA damage in the dentate gyrus in the P14 group was evaluated on P18, 1 day after the last session, using TUNEL staining. There was no difference in the number of TUNEL-positive cells after MRI compared with controls, neither in mature neurons, nor in newborn progenitors (BrdU/TUNEL double-labeled cells). Novel object recognition was performed to assess memory function 1 month after MRI. There was no difference in the recognition index observed after MRI compared with the control rats, neither for the E15, nor for the P14 group. In conclusion, repeated exposure to MRI did not appear to affect neurogenesis, cell death or memory function in rats, neither in late gestation (E15-E18) nor in young postnatal (P14-P17) rats.

  12. Posture-dependent Human 3He Lung Imaging in an Open-access MRI System

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    Posture-dependent Human 3He Lung Imaging in an Open-access MRI System: Initial Results1 Leo L. Tsai. Walsworth, PhD Rationale and Objectives. The human lung and its functions are extremely sensitive in determining lung function and heterogeneity of perfusion and ventilation. However, study of these effects

  13. FY08 Annual Report for Nuclear Resonance Fluorescence Imaging

    SciTech Connect (OSTI)

    Warren, Glen A.; Caggiano, Joseph A.

    2009-01-06

    FY08 annual report for project the "Nuclear Resonance Fluorescence Imaging" project. Reviews accomplishments of last 3 years, including U-235 signature search, comparison of different photon sources, and examination of NRF measurements using monochromatic photon source.

  14. SU-E-QI-19: Evaluation of a Clinical 1.5T MRI for Prostate Cancer MRS Imaging Using a In Vivo Tumor Model

    SciTech Connect (OSTI)

    Chen, X; Chen, L; Hensley, H; Cvetkovic, D; Fan, J; Ma, C; Zhang, C

    2014-06-15

    Purpose: Magnetic resonance spectroscopic (MRS) imaging may provide important bio-markers to distinguish normal/cancerous prostate tissue. While MRS imaging requires a high uniform magnetic field, the ability of a clinical 1.5T MRI to achieve a comparable MRS signal is of interest for radiation treatment planning/assessment. This study is to evaluate the MRS imaging of a 1.5T clinical MRI for prostate cancers by comparing with a small animal 7T MRS scanner. Methods: A tumor model was developed by implanting LNCaP tumor cells in nude mice prostates. Tumor was monitored 3 weeks after implantation using MRI, and MRS imaging was performed on the tumor area when the tumor reached around 1cm in diameter. The 1.5T GE clinical MR scanner and the 7T Bruker small animal MR scanner were used for each mouse. MR spectrums acquired with these scanners were analyzed and compared. The signals of Choline and Citrate were considered. Results: The prostate tumor MR spectrum under the 1.5T clinical MRI showed a similar spectrum pattern to that acquired using the 7T animal MRI. The Choline signal (3.2ppm) is clear and there is no clear peak for Citrate (2.6ppm). However, the signal magnitude for Choline is not dominant compared to the background signal under 1.5T MRI. Typical cancerous prostate tissue MR spectrum with an increased Choline signal and a reduced Citrate signal was observed. In addition, signal variation is noticeable between repeated spectrum scans. The average of these scans showed a comparable and consistent spectrum to those under 7T MRI. Conclusion: The clinical 1.5T MRI is able to acquire a MR spectrum for prostate cancer comparable to those acquired using a dedicated 7T MRS scanner. However, to achieve a consistent and reliable spectrum, multiple repeated scans were necessary to get a statistical result and reduce the noise-induced artifact. This work was supported in part by the National Cancer Institute Grant R21 CA131979 and R01CA172638.

  15. A Signal-Inducing Bone Cement for Magnetic Resonance Imaging-Guided Spinal Surgery Based on Hydroxyapatite and Polymethylmethacrylate

    SciTech Connect (OSTI)

    Wichlas, Florian, E-mail: florian.wichlas@charite.de; Seebauer, Christian J.; Schilling, Rene [University Charite, Center for Musculoskeletal Surgery (Germany); Rump, Jens [University Charite, Department of Radiology (Germany); Chopra, Sascha S. [University Charite, Center for Musculoskeletal Surgery (Germany); Walter, Thula; Teichgraeber, Ulf K. M. [University Charite, Department of Radiology (Germany); Bail, Hermann J. [University Charite, Center for Musculoskeletal Surgery (Germany)

    2012-06-15

    The aim of this study was to develop a signal-inducing bone cement for magnetic resonance imaging (MRI)-guided cementoplasty of the spine. This MRI cement would allow precise and controlled injection of cement into pathologic lesions of the bone. We mixed conventional polymethylmethacrylate bone cement (PMMA; 5 ml methylmethacrylate and 12 g polymethylmethacrylate) with hydroxyapatite (HA) bone substitute (2-4 ml) and a gadolinium-based contrast agent (CA; 0-60 {mu}l). The contrast-to-noise ratio (CNR) of different CA doses was measured in an open 1.0-Tesla scanner for fast T1W Turbo-Spin-Echo (TSE) and T1W TSE pulse sequences to determine the highest signal. We simulated MRI-guided cementoplasty in cadaveric spines. Compressive strength of the cements was tested. The highest CNR was (1) 87.3 (SD 2.9) in fast T1W TSE for cements with 4 {mu}l CA/ml HA (4 ml) and (2) 60.8 (SD 2.4) in T1W TSE for cements with 1 {mu}l CA/ml HA (4 ml). MRI-guided cementoplasty in cadaveric spine was feasible. Compressive strength decreased with increasing amounts of HA from 46.7 MPa (2 ml HA) to 28.0 MPa (4 ml HA). An MRI-compatible cement based on PMMA, HA, and CA is feasible and clearly visible on MRI images. MRI-guided spinal cementoplasty using this cement would permit direct visualization of the cement, the pathologic process, and the anatomical surroundings.

  16. Radiation-Induced Alterations in Mouse Brain Development Characterized by Magnetic Resonance Imaging

    SciTech Connect (OSTI)

    Gazdzinski, Lisa M.; Cormier, Kyle; Lu, Fred G.; Lerch, Jason P.; Department of Medical Biophysics, University of Toronto, Toronto ; Wong, C. Shun; Department of Medical Biophysics, University of Toronto, Toronto; Department of Radiation Oncology, University of Toronto, Toronto ; Nieman, Brian J.

    2012-12-01

    Purpose: The purpose of this study was to identify regions of altered development in the mouse brain after cranial irradiation using longitudinal magnetic resonance imaging (MRI). Methods and Materials: Female C57Bl/6 mice received a whole-brain radiation dose of 7 Gy at an infant-equivalent age of 2.5 weeks. MRI was performed before irradiation and at 3 time points following irradiation. Deformation-based morphometry was used to quantify volume and growth rate changes following irradiation. Results: Widespread developmental deficits were observed in both white and gray matter regions following irradiation. Most of the affected brain regions suffered an initial volume deficit followed by growth at a normal rate, remaining smaller in irradiated brains compared with controls at all time points examined. The one exception was the olfactory bulb, which in addition to an early volume deficit, grew at a slower rate thereafter, resulting in a progressive volume deficit relative to controls. Immunohistochemical assessment revealed demyelination in white matter and loss of neural progenitor cells in the subgranular zone of the dentate gyrus and subventricular zone. Conclusions: MRI can detect regional differences in neuroanatomy and brain growth after whole-brain irradiation in the developing mouse. Developmental deficits in neuroanatomy persist, or even progress, and may serve as useful markers of late effects in mouse models. The high-throughput evaluation of brain development enabled by these methods may allow testing of strategies to mitigate late effects after pediatric cranial irradiation.

  17. Investigation of Cryo-Cooled Microcoils for MRI 

    E-Print Network [OSTI]

    Godley, Richard Franklin

    2012-10-19

    . In this research, copper microcoils of two different geometries have been cryo- cooled using liquid nitrogen. Quality-factor (Q) measurements have been taken to quantify the reduction in resistance due to cryo-cooling. Image SNR has been compared between... Resonance MRI Magnetic Resonance Imaging MRSL Magnetic Resonance Systems Laboratory, College Station, TX NMR Nuclear Magnetic Resonance Q Quality Factor RF Radio Frequency RT Room Temperature SEA Single Echo Acquisition SNR...

  18. Surface-Based Analysis of Functional Magnetic Resonance Imaging Data

    E-Print Network [OSTI]

    Thompson, Paul

    Surface-Based Analysis of Functional Magnetic Resonance Imaging Data Theo G.M. van Erp1, Vikas Y School of Medicine, Los Angeles, CA 90095, USA Abstract. Surface-based visualization, atlases the integration of surface-based tech- niques with functional imaging data, combining surface-based nonlinear

  19. Wavelets and functional magnetic resonance imaging of the human brain

    E-Print Network [OSTI]

    Breakspear, Michael

    Wavelets and functional magnetic resonance imaging of the human brain Ed Bullmore,a,* Jalal Fadili Breakspeare a Brain Mapping Unit and Wolfson Brain Imaging Centre, University of Cambridge, Addenbrooke of Psychiatry (King's College), London, UK e Brain Dynamics Centre (Westmead Hospital) and School of Physics

  20. Registration and Analysis of Myocardial Perfusion Magnetic Resonance Images

    E-Print Network [OSTI]

    - imum upslope, peak and time-to-peak. Qualitative and quantitative validation is carried out of Denmark, DTU #12;2 #12;3 Preface This thesis is based on five months work at the section for Image This thesis presents the registration and analysis of myocardial perfusion mag- netic resonance images

  1. High-resolution magnetic resonance imaging and diffusion tensor imaging of the porcine temporomandibular joint disc

    E-Print Network [OSTI]

    Benavides, E.; Bilgen, M.; Al-Hafez, B.; Alrefae, T.; Wang, Y; Spencer, Paulette

    2014-01-28

    scanned on a 9.4?Tesla horizontal bore MRI scanner using an inductively coupled surface coil. High-resolution gradient-echo and diffusion-weighted spin-echo based images were obtained. The mean diffusivity and fractional anisotropy (FA) were computed...

  2. Method for nuclear magnetic resonance imaging

    DOE Patents [OSTI]

    Kehayias, J.J.; Joel, D.D.; Adams, W.H.; Stein, H.L.

    1988-05-26

    A method for in vivo NMR imaging of the blood vessels and organs of a patient characterized by using a dark dye-like imaging substance consisting essentially of a stable, high-purity concentration of D/sub 2/O in a solution with water.

  3. Parallel magnetic resonance imaging: characterization and comparison 

    E-Print Network [OSTI]

    Rane, Swati Dnyandeo

    2005-11-01

    coil configuration, k-space subsampling factor, k-space coverage in the imaging environment, there is a critical need to find the method giving the best results under certain imaging conditions. The tools developed in this research help the selection...

  4. An open-access, very-low-field MRI system for posture-dependent 3 lung imaging

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    An open-access, very-low-field MRI system for posture-dependent 3 He human lung imaging L.L. Tsai a imaging Lung imaging Open access a b s t r a c t We describe the design and operation of an open of the human lungs. This system permits the study of lung function in both horizontal and upright postures

  5. Instrumentation for parallel magnetic resonance imaging 

    E-Print Network [OSTI]

    Brown, David Gerald

    2007-04-25

    FIGURE 1 An example of a 2D Fourier encoded pulse sequence for MR imaging ..............20 2 Block diagram for an ideal analog mixer with an output bandpass filter ............28 3 Undersampling of a bandpass signal...

  6. Single echo acquisition magnetic resonance imaging 

    E-Print Network [OSTI]

    McDougall, Mary Preston

    2006-04-12

    limitations are already being approached. Parallel imaging methods (using multiple receiver coils to partially encode k-space) have offered some relief in the efforts and are rapidly becoming the focus of current endeavors to decrease scan time. Ideally...

  7. He Lung Imaging in an Open Access, Very-Low-Field Human Magnetic Resonance Imaging System

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    3 He Lung Imaging in an Open Access, Very-Low-Field Human Magnetic Resonance Imaging System R. W. Butler,6 F. W. Hersman,4 and R. L. Walsworth1 The human lung and its functions are extremely sensitive lung restrict sub- jects to lying horizontally. Imaging of human lungs using inhaled laser-polarized 3

  8. Prediction of Liver Function by Using Magnetic Resonance-based Portal Venous Perfusion Imaging

    SciTech Connect (OSTI)

    Cao Yue; Wang Hesheng; Johnson, Timothy D.; Pan, Charlie; Hussain, Hero; Balter, James M.; Normolle, Daniel; Ben-Josef, Edgar; Ten Haken, Randall K.; Lawrence, Theodore S.; Feng, Mary

    2013-01-01

    Purpose: To evaluate whether liver function can be assessed globally and spatially by using volumetric dynamic contrast-enhanced magnetic resonance imaging MRI (DCE-MRI) to potentially aid in adaptive treatment planning. Methods and Materials: Seventeen patients with intrahepatic cancer undergoing focal radiation therapy (RT) were enrolled in institution review board-approved prospective studies to obtain DCE-MRI (to measure regional perfusion) and indocyanine green (ICG) clearance rates (to measure overall liver function) prior to, during, and at 1 and 2 months after treatment. The volumetric distribution of portal venous perfusion in the whole liver was estimated for each scan. We assessed the correlation between mean portal venous perfusion in the nontumor volume of the liver and overall liver function measured by ICG before, during, and after RT. The dose response for regional portal venous perfusion to RT was determined using a linear mixed effects model. Results: There was a significant correlation between the ICG clearance rate and mean portal venous perfusion in the functioning liver parenchyma, suggesting that portal venous perfusion could be used as a surrogate for function. Reduction in regional venous perfusion 1 month after RT was predicted by the locally accumulated biologically corrected dose at the end of RT (P<.0007). Regional portal venous perfusion measured during RT was a significant predictor for regional venous perfusion assessed 1 month after RT (P<.00001). Global hypovenous perfusion pre-RT was observed in 4 patients (3 patients with hepatocellular carcinoma and cirrhosis), 3 of whom had recovered from hypoperfusion, except in the highest dose regions, post-RT. In addition, 3 patients who had normal perfusion pre-RT had marked hypervenous perfusion or reperfusion in low-dose regions post-RT. Conclusions: This study suggests that MR-based volumetric hepatic perfusion imaging may be a biomarker for spatial distribution of liver function, which could aid in individualizing therapy, particularly for patients at risk for liver injury after RT.

  9. A numerical approach : broadband technologies for efficient Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Mitsouras, Dimitrios, 1976-

    2004-01-01

    (cont.) independent receiver coils in parallel or time-axis compression, can be cast as complementary to broadband MRI encoding. This affords broadband non-Fourier MRI with time efficiencies over current fast MRI methods. ...

  10. Robust phase sensitive inversion recovery imaging 

    E-Print Network [OSTI]

    Garach, Ravindra Mahendrakumar

    2005-11-01

    Imaging. (August 2005) Garach, Ravindra Mahendrakumar, B.E., Gujarat University Chair of Advisory Committee: Dr. Jim Ji Inversion Recovery (IR) is a powerful tool for contrast manipulation in Mag- netic Resonance Imaging (MRI). IR can provide strong...

  11. Application of Parallel Imaging to Murine Magnetic Resonance Imaging 

    E-Print Network [OSTI]

    Chang, Chieh-Wei 1980-

    2012-09-21

    . This dissertation describes foundational level work to enable parallel imaging of mice on a 4.7 Tesla/40 cm bore research scanner. Reducing the size of the hardware setup associated with typical parallel imaging was an integral part of achieving the work, as animal...

  12. Investigating the Impact of the fMRI Environment and the Supine Position on Cognitive Function 

    E-Print Network [OSTI]

    Bell, Stephen

    2011-07-31

    Neuroimaging techniques, such as functional Magnetic Resonance Imaging (fMRI), have allowed researchers to investigate active neuronal structures in relation to cognitive theories using a non-invasive technique. Although ...

  13. Ready...Go: Amplitude of the fMRI Signal Encodes Expectation of Cue Arrival Time

    E-Print Network [OSTI]

    arrival time, as when a sprinter waits for the starting pistol? And what happens just after the starting pistol fires? Using functional magnetic resonance imaging (fMRI), we have discovered a novel correlate

  14. Solutions to various problems in reversible cooling fMRI studies

    E-Print Network [OSTI]

    Khachaturian, Mark Haig, 1979-

    2003-01-01

    Functional magnetic resonance imaging (fMRI) has been very useful in helping neuroscientists map the brain. One tool to investigate the interactions between brain regions is to disable a small region in the brain, and look ...

  15. Protein Polymer MRI Contrast Agents: Longitudinal Analysis of Biomaterials In Vivo

    E-Print Network [OSTI]

    Barron, Annelise E.

    Protein Polymer MRI Contrast Agents: Longitudinal Analysis of Biomaterials In Vivo Lindsay S by inadequate techniques for char- acterizing biomaterials in vivo. Magnetic resonance imaging is a tomographic- gitudinal noninvasive assessment of biomaterials in vivo. To distinguish biomaterials from surrounding

  16. Numerical field simulation for parallel transmission in MRI at 7 tesla

    E-Print Network [OSTI]

    Bernier, Jessica A. (Jessica Ashley)

    2011-01-01

    Parallel transmission (pTx) is a promising improvement to coil design that has been demonstrated to mitigate B1* inhomogeneity, manifest as center brightening, for high-field magnetic resonance imaging (MRI). Parallel ...

  17. Functional MRI To Evaluate “Sense of Self” following Perforator Flap Breast Reconstruction

    E-Print Network [OSTI]

    Caterson, Stephanie A.

    Background: Breast reconstruction is associated with high levels of patient satisfaction. Previous patient satisfaction studies have been subjective. This study utilizes functional magnetic resonance imaging (fMRI) to ...

  18. Off-resonance and detuned surface coils for B? inhomogeneity in 7-Tesla MRI

    E-Print Network [OSTI]

    Zakszewski, Elizabeth K

    2006-01-01

    A problem with high-field MRI is the lack of B1 homogeneity, particularly signal cancellation in the outer parts of the head. Here we attempt to correct this by adding surface coils. To adjust the mutual coupling, we vary ...

  19. Spectrally Resolved Magnetic Resonance Imaging of the XenonBiosensor

    SciTech Connect (OSTI)

    Hilty, Christian; Lowery, Thomas; Wemmer, David; Pines, Alexander

    2005-07-15

    Due to its ability to non-invasively record images, as well as elucidate molecular structure, nuclear magnetic resonance is the method of choice for applications as widespread as chemical analysis and medical diagnostics. Its detection threshold is, however, limited by the small polarization of nuclear spins in even the highest available magnetic fields. This limitation can, under certain circumstances, be alleviated by using hyper-polarized substances. Xenon biosensors make use of the sensitivity gain of hyperpolarized xenon to provide magnetic resonance detection capability for a specific low-concentration target. They consist of a cryptophane cage, which binds one xenon atom, and which has been connected via a linker to a targeting moiety such as a ligand or antibody. Recent work has shown the possibility of using the xenon biosensor to detect small amounts of a substance in a heterogeneous environment by NMR. Here, we demonstrate that magnetic resonance (MR) provides the capability to obtain spectrally and spatially resolved images of the distribution of immobilized biosensor, opening the possibility for using the xenon biosensor for targeted imaging.

  20. Noninvasive Monitoring of Microvascular Changes With Partial Irradiation Using Dynamic Contrast-Enhanced and Blood Oxygen Level-Dependent Magnetic Resonance Imaging

    SciTech Connect (OSTI)

    Lin, Yu-Chun [Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou, Taiwan (China) [Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou, Taiwan (China); Department of Electrical Engineering, Chang Gung University, Linkou, Taiwan (China); Department of Medical Imaging and Radiological Sciences, Chang Gung University, Linkou, Taiwan (China); Wang, Jiun-Jie [Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou, Taiwan (China) [Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou, Taiwan (China); Department of Medical Imaging and Radiological Sciences, Chang Gung University, Linkou, Taiwan (China); Hong, Ji-Hong [Department of Medical Imaging and Radiological Sciences, Chang Gung University, Linkou, Taiwan (China) [Department of Medical Imaging and Radiological Sciences, Chang Gung University, Linkou, Taiwan (China); Department of Radiation Oncology, Chang Gung Memorial Hospital, Linkou, Taiwan (China); Lin, Yi-Ping [Department of Radiation Oncology, Chang Gung Memorial Hospital, Linkou, Taiwan (China)] [Department of Radiation Oncology, Chang Gung Memorial Hospital, Linkou, Taiwan (China); Lee, Chung-Chi [Department of Medical Imaging and Radiological Sciences, Chang Gung University, Linkou, Taiwan (China) [Department of Medical Imaging and Radiological Sciences, Chang Gung University, Linkou, Taiwan (China); Department of Radiation Oncology, Chang Gung Memorial Hospital, Linkou, Taiwan (China); Wai, Yau-Yau; Ng, Shu-Hang; Wu, Yi-Ming [Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou, Taiwan (China) [Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou, Taiwan (China); Department of Medical Imaging and Radiological Sciences, Chang Gung University, Linkou, Taiwan (China); Wang, Chun-Chieh, E-mail: jjwang@adm.cgmh.org.tw [Department of Medical Imaging and Radiological Sciences, Chang Gung University, Linkou, Taiwan (China) [Department of Medical Imaging and Radiological Sciences, Chang Gung University, Linkou, Taiwan (China); Department of Radiation Oncology, Chang Gung Memorial Hospital, Linkou, Taiwan (China)

    2013-04-01

    Purpose: The microvasculature of a tumor plays an important role in its response to radiation therapy. Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) and blood oxygen level-dependent (BOLD) MRI are both sensitive to vascular characteristics. The present study proposed a partial irradiation approach to a xenograft tumor to investigate the intratumoral response to radiation therapy using DCE and BOLD MRI. Methods and Materials: TRAMP-C1 tumors were grown in C57BL/6J mice. Partial irradiation was performed on the distal half of the tumor with a single dose of 15 Gy. DCE MRI was performed to derive the endothelium transfer constant, K{sup trans}, using pharmacokinetic analysis. BOLD MRI was performed using quantitative R2* measurements with carbogen breathing. The histology of the tumor was analyzed using hematoxylin and eosin staining and CD31 staining to detect endothelial cells. The differences between the irradiated and nonirradiated regions of the tumor were assessed using K{sup trans} values, ?R2* values in response to carbogen and microvascular density (MVD) measurements. Results: A significantly increased K{sup trans} and reduced BOLD response to carbogen were found in the irradiated region of the tumor compared with the nonirradiated region (P<.05). Histologic analysis showed a significant aggregation of giant cells and a reduced MVD in the irradiated region of the tumor. The radiation-induced difference in the BOLD response was associated with differences in MVD and K{sup trans}. Conclusions: We demonstrated that DCE MRI and carbogen-challenge BOLD MRI can detect differential responses within a tumor that may potentially serve as noninvasive imaging biomarkers to detect microvascular changes in response to radiation therapy.

  1. Neuroscience Letters 392 (2006) 159164 Noxious heat induces fMRI activation in two anatomically

    E-Print Network [OSTI]

    Chabris, Christopher F.

    2006-01-01

    Neuroscience Letters 392 (2006) 159­164 Noxious heat induces fMRI activation in two anatomically; accepted 7 September 2005 Abstract Using functional magnetic resonance imaging (fMRI) we found were instructed on how to rate their pain intensity during the scan using a standard 11-point Likerts

  2. Multivariate and univariate analysis of continuous arterial spin labeling perfusion MRI in Alzheimer's

    E-Print Network [OSTI]

    Multivariate and univariate analysis of continuous arterial spin labeling perfusion MRI arterial spin labeling (CASL) magnetic resonance imaging (MRI) was combined with multivariate analysis and precuneus. When tested on extensive split-half analysis to map out the replicability of both multivariate

  3. Haptic System Design for MRI-Guided Needle Based Prostate Brachytherapy

    E-Print Network [OSTI]

    Camesano, Terri

    Gregory A. Cole Kevin Harrington Gregory S. Fischer ABSTRACT This paper presents the design of a hapticHaptic System Design for MRI-Guided Needle Based Prostate Brachytherapy Hao Su Weijian Shang system for prostate nee- dle brachytherapy under magnetic resonance imaging (MRI) guid- ance. This haptic

  4. Advancements in branched bottlebrush polymers for responsive, targeted imaging

    E-Print Network [OSTI]

    Sowers, Molly A. (Molly Ann)

    2015-01-01

    Multi-modality and stimuli responsive nanoparticles are promising platform materials for medical imaging and diagnostics. Specifically magnetic resonance imaging (MRI) and nearinfrared (NIR) fluorescent probes can be used ...

  5. Development of integrated imaging techniques for investigating biomarkers in glioblastoma

    E-Print Network [OSTI]

    Kim, Heisoog

    2011-01-01

    Cancer is a diverse disease with many manifestations. Various imaging modalities including magnetic resonance imaging (MRI) and positron emission tomography (PET) have been used to study human cancer. In this study, we ...

  6. Adaptive processing of thin structures to augment segmentation of dual-channel structural MRI of the human brain 

    E-Print Network [OSTI]

    Withers, James

    2010-01-01

    This thesis presents a method for the segmentation of dual-channel structural magnetic resonance imaging (MRI) volumes of the human brain into four tissue classes. The state-of-the-art FSL FAST segmentation software ...

  7. A within-subject ERP and fMRI investigation of orientation-specific recognition memory for pictures

    E-Print Network [OSTI]

    Curran, Tim

    Grit Herzmann1 , Mingwu Jin2 , Dietmar Cordes3 , and Tim Curran1 1 Department of Psychology resonance imaging (fMRI) (see Kim, 2010; Rugg & Curran, 2007; Skinner & Fernandes, 2007; Spaniol et al

  8. Magnetic resonance visualization of conductive structures by sequence-triggered direct currents and spin-echo phase imaging

    SciTech Connect (OSTI)

    Eibofner, Frank; Wojtczyk, Hanne; Graf, Hansjörg E-mail: drGraf@t-online.de; Clasen, Stephan

    2014-06-15

    Purpose: Instrument visualization in interventional magnetic resonance imaging (MRI) is commonly performed via susceptibility artifacts. Unfortunately, this approach suffers from limited conspicuity in inhomogeneous tissue and disturbed spatial encoding. Also, susceptibility artifacts are controllable only by sequence parameters. This work presents the basics of a new visualization method overcoming such problems by applying sequence-triggered direct current (DC) pulses in spin-echo (SE) imaging. SE phase images allow for background free current path localization. Methods: Application of a sequence-triggered DC pulse in SE imaging, e.g., during a time period between radiofrequency excitation and refocusing, results in transient field inhomogeneities. Dependent on the additional z-magnetic field from the DC, a phase offset results despite the refocusing pulse. False spatial encoding is avoided by DC application during periods when read-out or slice-encoding gradients are inactive. A water phantom containing a brass conductor (water equivalent susceptibility) and a titanium needle (serving as susceptibility source) was used to demonstrate the feasibility. Artifact dependence on current strength and orientation was examined. Results: Without DC, the brass conductor was only visible due to its water displacement. The titanium needle showed typical susceptibility artifacts. Applying triggered DC pulses, the phase offset of spins near the conductor appeared. Because SE phase images are homogenous also in regions of persistent field inhomogeneities, the position of the conductor could be determined with high reliability. Artifact characteristic could be easily controlled by amperage leaving sequence parameters unchanged. For an angle of 30° between current and static field visualization was still possible. Conclusions: SE phase images display the position of a conductor carrying pulsed DC free from artifacts caused by persistent field inhomogeneities. Magnitude and phase images are acquired simultaneously under the same conditions without the use of extra measurement time. The presented technique offers many advantages for precise instrument localization in interventional MRI.

  9. Fast and contrast-enhanced phase-sensitive magnetic resonance imaging 

    E-Print Network [OSTI]

    Son, Jong Bum

    2009-05-15

    as the resonance frequency (w0) of interested protons, 11 00w= ?B [2.1] where ? is the gyromagnetic ratio of a proton. MRI is primarily dependant on signals from the hydrogen proton (? = 2??42.5759 radians / Tesla) due to its...

  10. Direct Numerical Simulation of Pore-Scale Flow in a Bead Pack: Comparison with Magnetic Resonance Imaging Observations

    SciTech Connect (OSTI)

    Yang, Xiaofan; Scheibe, Timothy D.; Richmond, Marshall C.; Perkins, William A.; Vogt, Sarah J.; Codd, Sarah L.; Seymour, Joseph D.; Mckinley, Matthew I.

    2013-04-01

    A significant body of current research is aimed at developing methods for numerical simulation of flow and transport in porous media that explicitly resolve complex pore and solid geometries, and at utilizing such models to study the relationships between fundamental pore-scale processes and macroscopic manifestations at larger (i.e., Darcy) scales. A number of different numerical methods for pore-scale simulation have been developed, and have been extensively tested and validated for simplified geometries. However, validation of pore-scale simulations of fluid velocity for complex, three-dimensional (3D) pore geometries that are representative of natural porous media is challenging due to our limited ability to measure pore-scale velocity in such systems. Recent advances in magnetic resonance imaging (MRI) offer the opportunity to measure not only the pore geometry, but also local fluid velocities under steady-state flow conditions in 3D and with high spatial resolution. In this paper, we present a 3D velocity field measured at sub-pore resolution (tens of micrometers) over a centimeter-scale 3D domain using MRI methods. We have utilized the measured pore geometry to perform 3D simulations of Navier-Stokes flow over the same domain using direct numerical simulation techniques. We present a comparison of the numerical simulation results with the measured velocity field. It is shown that the numerical results match the observed velocity patterns well overall except for a variance and small systematic scaling which can be attributed to the known experimental error in the MRI measurements. The comparisons presented here provide strong validation of the pore-scale simulation methods and new insights for interpretation of uncertainty in MRI measurements of pore-scale velocity. This study also provides a potential benchmark for future comparison of other pore-scale simulation methods.

  11. A Novel MRI Marker for Prostate Brachytherapy

    SciTech Connect (OSTI)

    Frank, Steven J. [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)], E-mail: sjfrank@mdanderson.org; Stafford, R. Jason; Bankson, James A. [Department of Imaging Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Li Chun [Department of Experimental Diagnostic Imaging, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Swanson, David A. [Department of Urology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Kudchadker, Rajat J. [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Martirosyan, Karen S. [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX (United States)

    2008-05-01

    Purpose: Magnetic resonance imaging (MRI) is the optimal imaging modality for the prostate and surrounding critical organ structures. However, on MRI, the titanium radioactive seeds used for brachytherapy appear as black holes (negative contrast) and cannot be accurately localized. We sought to develop an encapsulated contrast agent marker (ECAM) with high-signal intensity on MRI to permit accurate localization of radioactive seeds with MRI during and after prostate brachytherapy. Methods and Materials: We investigated several agents with paramagnetic and superparamagnetic properties. The agents were injected into titanium, acrylic, and glass seeds, which were linked together in various combinations and imaged with MRI. The agent with the greatest T1-weighted signal was tested further in a canine prostate and agarose phantom. Studies were performed on a 1.5-T clinical MRI scanner. Results: The cobalt-chloride complex contrast (C4) agent with stoichiometry (CoCl{sub 2}){sub 0.8}(C{sub 2}H{sub 5}NO{sub 2}){sub 0.2} had the greatest T1-weighted signal (positive contrast) with a relaxivity ratio >1 (r{sub 2}/r{sub 1} = 1.21 {+-} 0.29). Acrylic-titanium and glass-titanium seed strands were clearly visualized with the encapsulated contrast agent marker. Conclusion: We have developed a novel ECAM that permits positive identification of the radioactive seeds used for prostate brachytherapy on MRI. Preclinical in vitro phantom studies and in vivo canine studies are needed to further optimize MRI sequencing techniques to facilitate MRI-based dosimetry.

  12. Novel mathematical modeling approaches to assess ischemic stroke lesion evolution on medical imaging 

    E-Print Network [OSTI]

    Rekik, Islem

    2014-11-28

    Stroke is a major cause of disability and death worldwide. Although different clinical studies and trials used Magnetic Resonance Imaging (MRI) to examine patterns of change in different imaging modalities (eg: perfusion ...

  13. “Calm Down Dear, It’s Only a Simulator.” An investigation into the effects of the fMRI environment on cognition. 

    E-Print Network [OSTI]

    Black, Ashley Anne

    2007-01-01

    Functional Magnetic Resonance Imaging (fMRI) is a useful tool which permits the observation of the brain’s neuronal activity in a non-invasive, on-line manner. The usefulness of the technique has however been questioned ...

  14. Surface plasmon resonance imaging of the enzymatic degradation of cellulose microfibrils

    E-Print Network [OSTI]

    Dutcher, John

    Surface plasmon resonance imaging of the enzymatic degradation of cellulose microfibrils Scott G with cellulose microfibrils using surface plasmon resonance (SPR) imaging. The cellulose microfibrils, obtained of the enzymes onto both the cellulose microfibrils and the bare surface, and the subsequent degradation

  15. Distortion-free magnetic resonance imaging in the zero-field limit

    SciTech Connect (OSTI)

    Kelso, Nathan; Lee, Seung-Kyun; Bouchard, Louis-S.; Demas, Vasiliki; Muck, Michael; Pines, Alexander; Clarke, John

    2009-07-09

    MRI is a powerful technique for clinical diagnosis and materials characterization. Images are acquired in a homogeneous static magnetic field much higher than the fields generated across the field of view by the spatially encoding field gradients. Without such a high field, the concomitant components of the field gradient dictated by Maxwell's equations lead to severe distortions that make imaging impossible with conventional MRI encoding. In this paper, we present a distortion-free image of a phantom acquired with a fundamentally different methodology in which the applied static field approaches zero. Our technique involves encoding with pulses of uniform and gradient field, and acquiring the magnetic field signals with a SQUID. The method can be extended to weak ambient fields, potentially enabling imaging in the Earth's field without cancellation coils or shielding. Other potential applications include quantum information processing and fundamental studies of long-range ferromagnetic interactions.

  16. Orientation-Dependent 3He Lung Imaging in an Open Access, Very-Low-Field Human MRI System

    E-Print Network [OSTI]

    Mair, R W; Patz, S; Rosen, M S; Ruset, I C; Topulos, G P; Tsai, L L; Butler, J P; Hersman, F W; Walsworth, R L

    2004-01-01

    Orientation-dependent imaging of human lungs is demonstrated using inhaled laser-polarized 3He gas and an open-access very-low-magnetic field (< 5 mT) MRI instrument. This prototype device employs a simple, low-cost electromagnet, with an open geometry that allows variation of the orientation of the imaging subject in a two-dimensional plane. Two-dimensional 3He images were acquired with 2 mm in-plane resolution from a subject in two orientations: lying supine, and sitting in a vertical position with one arm raised. The images show clear differences in lung shape and inhaled 3He gas distribution, consistent with the expected orientation dependence of pulmonary physiology.

  17. Portable MRI

    SciTech Connect (OSTI)

    Espy, Michelle A.

    2012-06-29

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  18. Approaches to Creating and Controlling Motion in MRI Gregory S. Fischer, Member, IEEE, Gregory Cole, Student Member, IEEE and Hao Su, Student Member, IEEE

    E-Print Network [OSTI]

    Camesano, Terri

    Approaches to Creating and Controlling Motion in MRI Gregory S. Fischer, Member, IEEE, Gregory Cole, Student Member, IEEE and Hao Su, Student Member, IEEE Abstract-- Magnetic Resonance Imaging (MRI) can is complicated by factors including: the high magnetic field strength, the requirement that such devices should

  19. A method for the optimization of the birdcage coil in MRI 

    E-Print Network [OSTI]

    Spence, Dan Kenrick

    1999-01-01

    In Magnetic Resonance Imaging (MRI), a volume coil is omen used to uniformly illuminate the sample being imaged with radio-frequency (RF) energy and then to receive the resulting MR signal. The coil is expected to achieve a high signal to noise...

  20. Highly Parallel Magnetic Resonance Imaging with a Fourth Gradient Channel for Compensation of RF Phase Patterns 

    E-Print Network [OSTI]

    Bosshard, John 1983-

    2012-08-20

    A fourth gradient channel was implemented to provide slice dependent RF coil phase compensation for arrays in dual-sided or "sandwich" configurations. The use of highly parallel arrays for single echo acquisition magnetic resonance imaging allows...

  1. Phase-based regional oxygen metabolism in magnetic resonance imaging at high field

    E-Print Network [OSTI]

    Fan, Audrey Peiwen

    2010-01-01

    Venous oxygen saturation (Yv) in cerebral veins and the cerebral metabolic rate of oxygen (CMRO?) are important indicators for brain function and disease. Phase-susceptibility measurements in magnetic resonance imaging ...

  2. Nuclear magnetic resonance imaging and analysis for determination of porous media properties 

    E-Print Network [OSTI]

    Uh, Jinsoo

    2007-04-25

    Advanced nuclear magnetic resonance (NMR) imaging methodologies have been developed to determine porous media properties associated with fluid flow processes. This dissertation presents the development of NMR experimental and analysis methodologies...

  3. Detecting tumor responses to treatment using hyperpolarized 13C magnetic resonance spectroscopic imaging

    E-Print Network [OSTI]

    2010-09-24

    2008, 453:940-943. doi:10.1038/nrc2289 Cite this article as: Brindle: Detecting tumor responses to treatment using hyperpolarized 13C magnetic resonance spectroscopic imaging. BMC Proceedings 2010 4(Suppl 2):O24. Correspondence: kmb1001@cam... Detecting tumor responses to treatment using hyperpolarized 13C magnetic resonance spectroscopic imaging Kevin M Brindle From 16th International Charles Heidelberger Symposium on Cancer Research Coimbra, Portugal. 26–28 September 2010 Patients with similar...

  4. Application of nuclear magnetic resonance imaging and spectroscopy to fluids in porous media 

    E-Print Network [OSTI]

    Mandava, Shanthi Sree

    1991-01-01

    and resolution of those saturations were developed with regards to the imaging method employed. The estimates so developed show that MRI can effectively monitor dynamic displacements for quantitative property estimation. An NMR spin-echo technique... in porous media was conducted with NMR Spectroscopy. A study of the effect of surrounding physical barriers on the diffusion of fluids in porous media was attempted. A Pulsed Gradient Spin-Echo sequence was developed to determine apparent self...

  5. Quantitative Clinical Evaluation of a Simultaneous PETI MRI Breast Imaging System

    SciTech Connect (OSTI)

    Schlyer D. J.; Schlyer, D.J.

    2013-04-03

    A prototype simultaneous PET-MRI breast scanner has been developed for conducting clinical studies with the goal of obtaining high resolution anatomical and functional information in the same scan which can lead to faster and better diagnosis, reduction of unwanted biopsies, and better patient care.

  6. Molecular imaging by optically-detected electron spin resonance of nitrogen-vacancies in nanodiamond

    E-Print Network [OSTI]

    Alex Hegyi; Eli Yablonovitch

    2012-12-11

    Molecular imaging refers to a class of noninvasive biomedical imaging techniques with the sensitivity and specificity to image biochemical variations in-vivo. An ideal molecular imaging technique visualizes a biochemical target according to a range of criteria, including high spatial and temporal resolution, high contrast relative to non-targeted tissues, depth-independent penetration into tissue, lack of harm to the organism under study, and low cost. Because no existing molecular imaging modality is ideal for all purposes, new imaging approaches are needed. Here we demonstrate a novel molecular imaging approach, called nanodiamond imaging, that uses nanodiamonds containing nitrogen-vacancy (NV) color centers as an imaging agent, and image nanodiamond targets in pieces of chicken breast. Nanodiamonds can be tagged with biologically active molecules so they bind to specific receptors; their distribution can then be quantified in-vivo via optically-detected magnetic resonance of the NVs. In effect, we are demonstrating Optically-Detected Functional-Electron-Spin-Resonance-Imaging, OD-f-ESRI. By combining optical detection with magnetic resonance, nanodiamond imaging achieves high sensitivity and high spatial resolution. It is absent of the complications of ionizing radiation, and the cost should be similar to all-optical imaging. Because nanodiamond imaging is limited by the depth of optical penetration into tissue to depths of a few cm, nanodiamond imaging should open up new avenues of investigation for applications where high depth penetration is not required, such as in small-animal imaging, tumor margin imaging, sentinel lymph node mapping, and perhaps mammography.

  7. Molecular imaging by optically-detected electron spin resonance of nitrogen-vacancies in nanodiamond

    E-Print Network [OSTI]

    Hegyi, Alex

    2012-01-01

    Molecular imaging refers to a class of noninvasive biomedical imaging techniques with the sensitivity and specificity to image biochemical variations in-vivo. An ideal molecular imaging technique visualizes a biochemical target according to a range of criteria, including high spatial and temporal resolution, high contrast relative to non-targeted tissues, depth-independent penetration into tissue, lack of harm to the organism under study, and low cost. Because no existing molecular imaging modality is ideal for all purposes, new imaging approaches are needed. Here we demonstrate a novel molecular imaging approach, called nanodiamond imaging, that uses nanodiamonds containing nitrogen-vacancy (NV) color centers as an imaging agent, and image nanodiamond targets in pieces of chicken breast. Nanodiamonds can be tagged with biologically active molecules so they bind to specific receptors; their distribution can then be quantified in-vivo via optically-detected magnetic resonance of the NVs. In effect, we are demo...

  8. Wavelets and statistical analysis of functional magnetic resonance images of the human brain

    E-Print Network [OSTI]

    Breakspear, Michael

    Wavelets and statistical analysis of functional magnetic resonance images of the human brain Ed Bullmore Brain Mapping Unit and Wolfson Brain Imaging Centre, University of Cambridge, Addenbrooke CNRS UMR 6072, Caen, France, Michael Breakspear Brain Dynamics Centre (Westmead Hospital) and School

  9. Introduction The delivery and interactive rendering and segmentation of magnetic resonance imaging (MRI) data

    E-Print Network [OSTI]

    Linsen, Lars

    2003],which optimizes the XWindows protocol transparently by removing unnecessary round will concentrate on how to integrate these toolkits transparently into a web-based multi-user application framework.This is completely transparent to the application using VTK. We observed a considerable decrease in netload

  10. Internal Fiducial Markers and Susceptibility Effects in MRI-Simulation and Measurement of Spatial Accuracy

    SciTech Connect (OSTI)

    Jonsson, Joakim H.; Garpebring, Anders; Karlsson, Magnus G.; Nyholm, Tufve

    2012-04-01

    Background: It is well-known that magnetic resonance imaging (MRI) is preferable to computed tomography (CT) in radiotherapy target delineation. To benefit from this, there are two options available: transferring the MRI delineated target volume to the planning CT or performing the treatment planning directly on the MRI study. A precondition for excluding the CT study is the possibility to define internal structures visible on both the planning MRI and on the images used to position the patient at treatment. In prostate cancer radiotherapy, internal gold markers are commonly used, and they are visible on CT, MRI, x-ray, and portal images. The depiction of the markers in MRI are, however, dependent on their shape and orientation relative the main magnetic field because of susceptibility effects. In the present work, these effects are investigated and quantified using both simulations and phantom measurements. Methods and Materials: Software that simulated the magnetic field distortions around user defined geometries of variable susceptibilities was constructed. These magnetic field perturbation maps were then reconstructed to images that were evaluated. The simulation software was validated through phantom measurements of four commercially available gold markers of different shapes and one in-house gold marker. Results: Both simulations and phantom measurements revealed small position deviations of the imaged marker positions relative the actual marker positions (<1 mm). Conclusion: Cylindrical gold markers can be used as internal fiducial markers in MRI.

  11. 2007 Nature Publishing Group Nuclear magnetic resonance imaging

    E-Print Network [OSTI]

    Leonardo, Degiorgi

    to sense the magnetic force generated between the tip and spins in a sample. Magnetic resonance is used for the present work is the development of magnetic tips that generate magnetic field gradients as high as 1 of the technique on a patterned CaF2 test object. Unlike the permanent magnet tips previously used for

  12. Image Functional Modeling of the Lung Using Hyperpolarized 3He MRI Jennifer Kenyon, Nora T. Tgavalekos, and K.R. Lutchen

    E-Print Network [OSTI]

    Lutchen, Kenneth

    Image Functional Modeling of the Lung Using Hyperpolarized 3He MRI Jennifer Kenyon, Nora T and decreased alveoli ventilation. ASTHMATIC ASM ·One way to assess asthmatic lung structure is through a new noble gas. ANATOMICALLY-BASED MODELING ·This model is able to predict whole lung mechanics based

  13. 1,2-Hydroxypyridonates as Contrast Agents for Magnetic ResonanceImaging: TREN-1,2-HOPO

    SciTech Connect (OSTI)

    Jocher, Christoph J.; Moore, Evan G.; Xu, Jide; Avedano, Stefano; Botta, Mauro; Aime, Silvio; Raymond, Kenneth N.

    2007-05-08

    1,2-Hydroxypyridinones (1,2-HOPO) form very stable lanthanide complexes that may be useful as contrast agents for Magnetic Resonance Imaging (MRI). X-ray diffraction of single crystals established that the solid state structures of the Eu(III) and the previously reported [Inorg. Chem. 2004, 43, 5452] Gd(III) complex are identical. The recently discovered sensitizing properties of 1,2-HOPO chelates for Eu(III) luminescence allow direct measurement of the number if water molecules in the metal complex. Fluorescence measurements of the Eu(III) complex corroborate that in solution two water molecules coordinate the lanthanide (q = 2) as proposed from the analysis of NMRD profiles. In addition, fluorescence measurements have verified the anion binding interactions of lanthanide TREN-1,2-HOPO complexes in solution, studied by relaxivity, revealing only very weak oxalate binding (K{sub A} = 82.7 {+-} 6.5 M{sup -1}). Solution thermodynamic studies of the metal complex and free ligand have been carried out using potentiometry, spectrophotometry and fluorescence spectroscopy. The metal ion selectivity of TREN-1,2-HOPO supports the feasibility of using 1,2-HOPO ligands for selective lanthanide binding [pGd = 19.3 (2); pZn = 15.2 (2), pCa = 8.8 (3)].

  14. Imaging transport resonances in the quantum Hall effect

    E-Print Network [OSTI]

    Steele, Gary Alexander

    2006-01-01

    We image charge transport in the quantum Hall effect using a scanning charge accumulation microscope. Applying a DC bias voltage to the tip induces a highly resistive ring-shaped incompressible strip (IS) in a very high ...

  15. Simultaneous Electroencephalography and Functional Magnetic Resonance Imaging of General Anesthesia

    E-Print Network [OSTI]

    Purdon, Patrick Lee

    It has been long appreciated that anesthetic drugs induce stereotyped changes in electroencephalogram (EEG), but the relationships between the EEG and underlying brain function remain poorly understood. Functional imaging ...

  16. Fast Reference-Based MRI

    E-Print Network [OSTI]

    Weizman, Lior; Ben-Basaht, Dafna

    2015-01-01

    In many clinical MRI scenarios, existing imaging information can be used to significantly shorten acquisition time or to improve Signal to Noise Ratio (SNR). In some cases, a previously acquired image can serve as a reference image, that may exhibit similarity to the image being acquired. Examples include similarity between adjacent slices in high resolution MRI, similarity between various contrasts in the same scan and similarity between different scans of the same patient. In this paper we present a general framework for utilizing reference images for fast MRI. We take into account that the reference image may exhibit low similarity with the acquired image and develop an iterative weighted approach for reconstruction, which tunes the weights according to the degree of similarity. Experiments demonstrate the performance of the method in three different clinical MRI scenarios: SNR improvement in high resolution brain MRI, utilizing similarity between T2-weighted and fluid-attenuated inversion recovery (FLAIR)...

  17. Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2007

    E-Print Network [OSTI]

    California at San Diego, University of

    velocity well. b. Acquire a 3D TOF image of the vessel, with the location of the 2D PC image the (volts/amps) scale labeled on the gradient amp test point, and a scaling of 4G/cm at 250A. Turn where all the major vessels going in and out of the head are clear and appear to be flowing straight

  18. Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2008

    E-Print Network [OSTI]

    California at San Diego, University of

    velocity well. b. Acquire a 3D TOF image of the vessel, with the location of the 2D PC image the (volts/amps) scale labeled on the gradient amp test point, and a scaling of 4G/cm at 250A. Turn where all the major vessels going in and out of the head are clear and appear to be flowing straight

  19. MRI-based Microrobotic system for the Propulsion and Navigation of Ferromagnetic Microcapsules

    E-Print Network [OSTI]

    Boyer, Edmond

    MRI-based Microrobotic system for the Propulsion and Navigation of Ferromagnetic Microcapsules 3-D navigation of a microdevice in blood ves- sels, namely: (i) vessel path planner, (ii) magnetic, magnetic resonance imaging, minimally invasive interventions, real-time control Email address: antoine

  20. COMPUTATIONAL STUDIES OF CONTROLLED NANOPARTICLE AGGLOMERATIONS FOR MRI-GUIDED NANOROBOTIC DRUG-DELIVERY SYSTEMS

    E-Print Network [OSTI]

    Mavroidis, Constantinos

    groups have employed magnetized micro/ nanoparticles and have implemented magnetic propulsion techniques implementation is difficult and medically invasive. Finally, magnetic propulsion techniques #12;other thanEastern University Boston, MA 02115 mavro@coe.neu.edu ABSTRACT Magnetic Resonance Imaging (MRI) guided nanorobotic

  1. The neural correlates of statistical learning in a word segmentation task: An fMRI study

    E-Print Network [OSTI]

    Aslin, Richard N.

    language Sequence learning Broca's area LIFG a b s t r a c t Functional magnetic resonance imaging (f of this statistical learning mechanism in the do- main of language acquisition (see also Saffran, Aslin, & NewportThe neural correlates of statistical learning in a word segmentation task: An fMRI study Elisabeth

  2. SLIDING MODE CONTROL OF PIEZOELECTRIC VALVE REGULATED PNEUMATIC ACTUATOR FOR MRI-COMPATIBLE ROBOTIC INTERVENTION

    E-Print Network [OSTI]

    Camesano, Terri

    @wpi.edu ABSTRACT This paper presents the design of a magnetic resonance imaging (MRI) compatible pneumatic actuator@wpi.edu Gregory S. Fischer Mechanical Engineering Worcester Polytechnic Institute Worcester, MA 01609 gfischer provides high-fidelity soft tissue contrast and high spatial resolution. However, the high- field magnetic

  3. An analysis of the PERL Magnetic Resonance Imaging theory and implementation 

    E-Print Network [OSTI]

    Kremkus, Mark Christian

    2013-02-22

    . . Expenmentation. 27 RESULTS AND DISCUSSION . 29 CONCLUSIONS . REFERENCES. APPENDIX A ? FUNDAMENTALS OF MRI . . 32 33 Resolut&on and F&eld of Viev . Contrast Rad&t&-frequencf Coils. Cirad&ent Coils . . 41 . . 42 . . . 44 . . 43 APPENDIX B - BURST... Coil Lavout 14 F&sure 3 2 Field along x &n lmag&ng Re ion for N 15 F&gure 3. 3 F&eld ulon . r in Imagmg Reg&on fi&r &V=6 . . Figure 3 4 I icld along i. &n Imaging Reg&on for N= J(&0 Figure 3 5 I'ield Strength vs. L Figure 3 6 Fiekl Pattern Along x...

  4. Integrated microchip incorporating atomic magnetometer and microfluidic channel for NMR and MRI

    DOE Patents [OSTI]

    Ledbetter, Micah P. (Oakland, CA); Savukov, Igor M. (Los Alamos, NM); Budker, Dmitry (El Cerrito, CA); Shah, Vishal K. (Plainsboro, NJ); Knappe, Svenja (Boulder, CO); Kitching, John (Boulder, CO); Michalak, David J. (Berkeley, CA); Xu, Shoujun (Houston, TX); Pines, Alexander (Berkeley, CA)

    2011-08-09

    An integral microfluidic device includes an alkali vapor cell and microfluidic channel, which can be used to detect magnetism for nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). Small magnetic fields in the vicinity of the vapor cell can be measured by optically polarizing and probing the spin precession in the small magnetic field. This can then be used to detect the magnetic field of in encoded analyte in the adjacent microfluidic channel. The magnetism in the microfluidic channel can be modulated by applying an appropriate series of radio or audio frequency pulses upstream from the microfluidic chip (the remote detection modality) to yield a sensitive means of detecting NMR and MRI.

  5. Bistable illusory rebound motion: Event-related functional magnetic resonance imaging of perceptual states and switches

    E-Print Network [OSTI]

    Bucci, David J.

    Bistable illusory rebound motion: Event-related functional magnetic resonance imaging of perceptual of a recently discovered visual illusion that we call Fillusory rebound motion_ (IRM) are described. This illusion is remarkable because motion is perceived in the absence of any net motion energy in the stimulus

  6. Magnetic Resonance Imaging 1 A new global optimization algorithm and its application to a

    E-Print Network [OSTI]

    Neumaier, Arnold

    by the uniformity of the magnetic field generated by this magnet, in that, the more uniform is the magnetic field a low field dedicated magnet is that of using permanent magnets surrounded by an iron yoke to amplifyMagnetic Resonance Imaging 1 A new global optimization algorithm and its application to a Magnetic

  7. Acoustic resonances in microfluidic chips: full-image micro-PIV experiments and numerical simulations

    E-Print Network [OSTI]

    of the corresponding acoustic wave equation. 1. Introduction For the typical dimensions of microfluidic structures and small 1 mm particles can be understood in terms of the acoustic eigenmodes or standing ultra-sound wavesAcoustic resonances in microfluidic chips: full-image micro-PIV experiments and numerical

  8. Detection of Tumors in Dynamic Magnetic Resonance Images using Principal Component Analysis

    E-Print Network [OSTI]

    Detection of Tumors in Dynamic Magnetic Resonance Images using Principal Component Analysis David Alberg Holm (1-2), Thomas Bøvith (2), Cecilia Cappellin (3) (1) Danish Research Centre for Magnetic different tissue classes. For this purpose, two methods were developed and combined. Data Eight mice bearing

  9. A REAL TIME 3D VISUALIZATION PROTOTYPE FOR INTERVENTIONAL MAGNETIC RESONANCE IMAGING

    E-Print Network [OSTI]

    Schumann, Heidrun

    A REAL TIME 3D VISUALIZATION PROTOTYPE FOR INTERVENTIONAL MAGNETIC RESONANCE IMAGING JENS FISCHER­invasive examinations. This prototype allows simultaneous visualization of three different types of data: a 3D­Magnetic@informatik.uni­rostock.de Abstract: This paper describes a prototype of a visualization system which is designed to support

  10. RF Pulse Design for Parallel Excitation in Magnetic Resonance Imaging 

    E-Print Network [OSTI]

    Liu, Yinan

    2012-07-16

    ? ?= (2.1) where ? is the gyromagnetic ratio. For 1H, ? = 42.58MHz/Tesla. 5 Figure 2.1. Precession of a nuclear spin about an external magnetic field. The imaging of an object relies on the bulk precession of the hydrogen spins in water...

  11. Rotating-frame gradient fields for magnetic resonance imaging and nuclear magnetic resonance in low fields

    DOE Patents [OSTI]

    Bouchard, Louis-Serge; Pines, Alexander; Demas, Vasiliki

    2014-01-21

    A system and method for Fourier encoding a nuclear magnetic resonance (NMR) signal is disclosed. A static magnetic field B.sub.0 is provided along a first direction. An NMR signal from the sample is Fourier encoded by applying a rotating-frame gradient field B.sub.G superimposed on the B.sub.0, where the B.sub.G comprises a vector component rotating in a plane perpendicular to the first direction at an angular frequency .omega.in a laboratory frame. The Fourier-encoded NMR signal is detected.

  12. Novel image processing techniques to better understand white matter disruption in multiple sclerosis

    E-Print Network [OSTI]

    In Multiple Sclerosis (MS) patients, conventional magnetic resonance imaging (MRI) shows a pattern of white rights reserved. Keywords: Multiple Sclerosis; Diffusion Tensor MRI; Atlas; Visualization; Tractography Institutes of Health, USA, RG 3478A2/2 from the National Multiple Sclerosis Society, USA, and NSF ITR 0426558

  13. Ultra-low field nuclear magnetic resonance and magnetic resonance imaging to discriminate and identify materials

    DOE Patents [OSTI]

    Kraus, Robert H. (Los Alamos, NM); Matlashov, Andrei N. (Los Alamos, NM); Espy, Michelle A. (Los Alamos, NM); Volegov, Petr L. (Los Alamos, NM)

    2010-03-30

    An ultra-low magnetic field NMR system can non-invasively examine containers. Database matching techniques can then identify hazardous materials within the containers. Ultra-low field NMR systems are ideal for this purpose because they do not require large powerful magnets and because they can examine materials enclosed in conductive shells such as lead shells. The NMR examination technique can be combined with ultra-low field NMR imaging, where an NMR image is obtained and analyzed to identify target volumes. Spatial sensitivity encoding can also be used to identify target volumes. After the target volumes are identified the NMR measurement technique can be used to identify their contents.

  14. GPU-accelerated denoising of 3D magnetic resonance images

    SciTech Connect (OSTI)

    Howison, Mark; Wes Bethel, E.

    2014-05-29

    The raw computational power of GPU accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. In practice, applying these filtering operations requires setting multiple parameters. This study was designed to provide better guidance to practitioners for choosing the most appropriate parameters by answering two questions: what parameters yield the best denoising results in practice? And what tuning is necessary to achieve optimal performance on a modern GPU? To answer the first question, we use two different metrics, mean squared error (MSE) and mean structural similarity (MSSIM), to compare denoising quality against a reference image. Surprisingly, the best improvement in structural similarity with the bilateral filter is achieved with a small stencil size that lies within the range of real-time execution on an NVIDIA Tesla M2050 GPU. Moreover, inappropriate choices for parameters, especially scaling parameters, can yield very poor denoising performance. To answer the second question, we perform an autotuning study to empirically determine optimal memory tiling on the GPU. The variation in these results suggests that such tuning is an essential step in achieving real-time performance. These results have important implications for the real-time application of denoising to MR images in clinical settings that require fast turn-around times.

  15. Morphology and development of the human vocal tract: A study using magnetic resonance imaging

    E-Print Network [OSTI]

    Fitch, Tecumseh

    which have generally focused on bony struc- tures vertebral column, skull base, hyoid bone, etc. , MRI

  16. An RF dosimeter for independent SAR measurement in MRI scanners

    SciTech Connect (OSTI)

    Qian, Di; Bottomley, Paul A.; El-Sharkawy, AbdEl-Monem M.; Edelstein, William A.

    2013-12-15

    Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B{sub 1}) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ?3%. With the torso landmarked at the xiphoid, human adult whole?body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average independent of the imaging subject, albeit with fluctuations. Conclusions: Our 3T RF dosimeter and transducers accurately measure RF exposure in body-equivalent loads and provide scanner-independent assessments of whole-body RF power deposition for establishing safety compliance useful for MRI sequence and device testing.

  17. The combination of EEG Source Imaging and EEG-correlated functional MRI to map epileptic networks

    E-Print Network [OSTI]

    Daunizeau, Jean

    interpretation to localize abnormal electrical activity. EEG source imaging (ESI) has transformed conventional the distribution of three-dimensional intracerebral electrical activity giving rise to the recorded scalp activity (EEG) recording of the human brain performed by Hans Berger in 1929, study of the brain of epileptic

  18. MRI of the lung using hyperpolarized He-3 at very low magnetic field (3 mT)

    E-Print Network [OSTI]

    Bidinosti, C P; Tastevin, G; Vignaud, A; Nacher, P J

    2004-01-01

    Optical pumping of He-3 produces large (hyper) nuclear-spin polarizations independent of the magnetic resonance imaging (MRI) field strength. This allows lung MRI to be performed at reduced fields with many associated benefits, such as lower tissue susceptibility gradients and decreased power absorption rates. Here we present results of 2D imaging as well as accurate 1D gas diffusion mapping of the human lung using He-3 at very low field (3 mT). Furthermore, measurements of transverse relaxation in zero applied gradient are shown to accurately track pulmonary oxygen partial pressure, opening the way for novel imaging sequences.

  19. 232 OPTICS LETTERS / Vol. 29, No. 3 / February 1, 2004 Off-resonant defocus-contrast imaging of cold atoms

    E-Print Network [OSTI]

    Scholten, Robert

    of column-density images of cold atoms, using a noninterferometric phase- recovery technique based prospects for simple, nondestructive imaging of atoms in magnetic and optical traps and condensates. © 2004 is predominant, despite its limited dynamic range and recoil heating. Off-resonant phase-imaging tech- niques

  20. Medical Image Segmentation Xiaolei Huang

    E-Print Network [OSTI]

    Huang, Xiaolei

    . The National Electrical Manufacturers Association (NEMA) holds the copyright to the DICOM standard. Medical (CAT), Magnetic Resonance Imaging (MRI), Ultrasound, and X-Ray, in standard DICOM formats are often and Communications in Medicine (DICOM) standard is created as a cooperative international standard for communication

  1. Combined PET/MRI scanner

    DOE Patents [OSTI]

    Schlyer, David (Bellport, NY); Woody, Craig L. (Setauket, NY); Rooney, William (Miller Place, NY); Vaska, Paul (Sound Beach, NY); Stoll, Sean (Wading River, NY); Pratte, Jean-Francois (Stony Brook, NY); O'Connor, Paul (Bellport, NY)

    2007-10-23

    A combined PET/MRI scanner generally includes a magnet for producing a magnetic field suitable for magnetic resonance imaging, a radiofrequency (RF) coil disposed within the magnetic field produced by the magnet and a ring tomograph disposed within the magnetic field produced by the magnet. The ring tomograph includes a scintillator layer for outputting at least one photon in response to an annihilation event, a detection array coupled to the scintillator layer for detecting the at least one photon outputted by the scintillator layer and for outputting a detection signal in response to the detected photon and a front-end electronic array coupled to the detection array for receiving the detection signal, wherein the front-end array has a preamplifier and a shaper network for conditioning the detection signal.

  2. Method and apparatus for molecular imaging using X-rays at resonance wavelengths

    DOE Patents [OSTI]

    Chapline, Jr., George F. (Alamo, CA)

    1985-01-01

    Holographic X-ray images are produced representing the molecular structure of a microscopic object, such as a living cell, by directing a beam of coherent X-rays upon the object to produce scattering of the X-rays by the object, producing interference on a recording medium between the scattered X-rays from the object and unscattered coherent X-rays and thereby producing holograms on the recording surface, and establishing the wavelength of the coherent X-rays to correspond with a molecular resonance of a constituent of such object and thereby greatly improving the contrast, sensitivity and resolution of the holograms as representations of molecular structures involving such constituent. For example, the coherent X-rays may be adjusted to the molecular resonant absorption line of nitrogen at about 401.3 eV to produce holographic images featuring molecular structures involving nitrogen.

  3. Combining MRI with PET for partial volume correction improves image-derived input functions in mice

    E-Print Network [OSTI]

    Evans, Eleanor; Buonincontri, Guido; Izquierdo, David; Methner, Carmen; Hawkes, Rob C.; Ansorge, Richard E.; Krieg, Thomas; Carpenter, T. Adrian; Sawiak, Stephen J.

    2015-06-05

    , CB2 0QQ (e-mail: gb396@cam.ac.uk). D. Izquierdo is with the Athinoula A. Martinos Center for Biomedical Imaging, 149 Thirteenth Street, Suite 2301, Charlestown, MA, 02129 (e-mail: davidizq@nmr.mgh.harvard.edu). C. Methner was with the Department... (DOUBLE-CLICK HERE TO EDIT) Am. J. Roentgenol., 195 (2), pp. 310–320, 2010. [4] P. Dupont...

  4. Minute Effects of Sex on the Aging Brain: A Multisample Magnetic Resonance Imaging Study of Healthy Aging and Alzheimer's Disease

    E-Print Network [OSTI]

    Fjell, Anders M.

    Age is associated with substantial macrostructural brain changes. While some recent magnetic resonance imaging studies have reported larger age effects in men than women, others find no sex differences. As brain morphometry ...

  5. AN APPROACH FOR INTERSUBJECT ANALYSIS OF 3D BRAIN IMAGES BASED ON CONFORMAL GEOMETRY

    E-Print Network [OSTI]

    Hua, Jing

    ABSTRACT Recent advances in imaging technologies, such as Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET) and Diffusion Tensor Imaging (DTI) have accelerated brain research in many aspects. In order to better understand the synergy of the many processes involved in normal brain function

  6. Threshold Doses for Focal Liver Reaction After Stereotactic Ablative Body Radiation Therapy for Small Hepatocellular Carcinoma Depend on Liver Function: Evaluation on Magnetic Resonance Imaging With Gd-EOB-DTPA

    SciTech Connect (OSTI)

    Sanuki, Naoko; Takeda, Atsuya; Oku, Yohei; Eriguchi, Takahisa; Nishimura, Shuichi; Aoki, Yosuke; Mizuno, Tomikazu; Iwabuchi, Shogo; Kunieda, Etsuo

    2014-02-01

    Purpose: Focal liver reaction (FLR) appears on radiographic images after stereotactic ablative body radiation therapy (SABR) in patients with hepatocellular carcinoma (HCC) and chronic liver disease. We investigated the threshold dose (TD) of FLR and possible factors affecting the TD on gadoxetate acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI). Methods and Materials: In 50 patients who were treated with SABR for small HCC and followed up by MRI for >6 months, FLR, seen as a hypointense area, was evaluated on the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI. The follow-up MRI with the largest extent of FLR was fused to the planning computed tomography (CT) image, and patients with good image fusion concordance were eligible. After delineating the border of the FLR manually, a dose–volume histogram was used to identify the TD for the FLR. Clinical and volumetric factors were analyzed for correlation with the TD. Results: A total of 45 patients were eligible for analysis with a median image fusion concordance of 84.9% (range, 71.6-95.4%). The median duration between SABR and subsequent hepatobiliary phase MRI with the largest extent of FLR was 3 months (range, 1-6 months). The median TD for FLR was 28.0 Gy (range, 22.3-36.4 Gy). On univariate analysis, pre-treatment Child-Pugh (CP) score and platelet count were significantly correlated with the TD. On multiple linear regression analysis, CP score was the only parameter that predicted TD. Median TDs were 30.5 Gy (range, 26.2.3-36.4 Gy) and 25.2 Gy (range, 22.3-27.5 Gy) for patients with CP-A and CP-B disease, respectively. Conclusion: The TD was significantly correlated with baseline liver function. We propose 30 Gy for CP-A disease and 25 Gy for CP-B disease in 5 fractions as TDs for FLR after SABR for patients with HCC and chronic liver disease. Use of these TDs will help to predict potential loss of liver tissue after SABR.

  7. PUBLICATIONS IN REFEREED JOURNALS Aubin M., Faddegon, B. and Pouliot J., Clinical Electron Beam Verification with an a-Si Electronic Portal Imaging Device, Submitted

    E-Print Network [OSTI]

    Pouliot, Jean

    in inverse planned HDR prostate brachytherapy for dose escalation of DIL defined by combined MRI., and Hsu I.C., Inverse Planning for the Magnetic Resonance Imaging (MRI)- Based Intracavitary Brachytherapy III M., Hsu I-C., High Dose Rate (HDR) Brachytherapy Salvage for Local Prostate Recurrence After

  8. VASCULAR-INTERVENTIONAL Haemodynamic imaging of thoracic stent-grafts

    E-Print Network [OSTI]

    Nicoud, Franck

    , depicting different patterns of flow (laminar, turbulent, stenosis-like) and local alterations of parietalVASCULAR-INTERVENTIONAL Haemodynamic imaging of thoracic stent-grafts by computational fluid combining mag- netic resonance imaging (MRI) and computational fluid dynamics (CFD) to obtain a patient

  9. IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 44, NO. 6, JUNE 2009 1805 A Spectral-Scanning Nuclear Magnetic Resonance

    E-Print Network [OSTI]

    Hajimiri, Ali

    resonance detection and analysis is tunable from 1 kHz to 37 MHz, corresponding to 0­0.9 T magnetization- troscopy, magnetic resonance imaging (MRI), coherent detection, Torrey-Bloch equation, nuclear magnetic keeping the sensitivity, detection time, spectral resolution, and the relative-to-sample-size spatial res

  10. Directed evolution of a magnetic resonance imaging contrast agent for noninvasive imaging of dopamine

    E-Print Network [OSTI]

    Shapiro, Mikhail G.

    The development of molecular probes that allow in vivo imaging of neural signaling processes with high temporal and spatial resolution remains challenging. Here we applied directed evolution techniques to create magnetic ...

  11. INVESTIGATION OF THERAPY IMPROVEMENT USING REAL-TIME PHOTOACOUSTIC IMAGING GUIDED HIGH INTENSITY FOCUSED ULTRASOUND

    E-Print Network [OSTI]

    Cui, Huizhong

    2013-05-31

    . Although several groups showed that magnetic resonance imaging (MRI),[32, 91, 92] thermoacoustic tomography (TAT),[93] ultrasound imaging[25, 94] have the capabilities of monitoring the thermal lesion generated by HIFU in the targeted region, PAI has... modes (such as head and neck imaging), special RF coils are used to fit closely to the patient’s anatomy, and these coils will interfere with HIFU transducer placement. Photoacoustic imaging, also called optoacoustic imaging or thermoacoustic imaging...

  12. Controlled-Resonant Surface Tapping-Mode Scanning Probe Electrospray Ionization Mass Spectrometry Imaging

    SciTech Connect (OSTI)

    Lorenz, Matthias; Ovchinnikova, Olga S; Kertesz, Vilmos; Van Berkel, Gary J

    2014-01-01

    This paper reports on the advancement of a controlled-resonance surface tapping-mode single capillary liquid junction extraction/ESI emitter for mass spectrometry imaging. The basic instrumental setup and the general operation of the system were discussed and optimized performance metrics were presented. The ability to spot sample, lane scan and chemically image in an automated and controlled fashion were demonstrated. Rapid, automated spot sampling was demonstrated for a variety of compound types including the cationic dye basic blue 7, the oligosaccharide cellopentaose, and the protein equine heart cytochrome c. The system was used for lane scanning and chemical imaging of the cationic dye crystal violet in inked lines on glass and for lipid distributions in mouse brain thin tissue sections. Imaging of the lipids in mouse brain tissue under optimized conditions provided a spatial resolution of approximately 35 m based on the ability to distinguish between features observed both in the optical and mass spectral chemical images. The sampling spatial resolution of this system was comparable to the best resolution that has been reported for other types of atmospheric pressure liquid extraction-based surface sampling/ionization techniques used for mass spectrometry imaging.

  13. Using co-cultures expressing fluorescence resonance energy transfer based protein biosensors to simultaneously image caspase-3 and Ca2+

    E-Print Network [OSTI]

    Using co-cultures expressing fluorescence resonance energy transfer based protein biosensors received: 8 June 2005; Accepted 11 June 2005 Key words: biosensor, fluorescence imaging, fluorescence)-based protein biosensors allow the spatial and temporal imaging of signaling events in living cells. However

  14. Abstract--For the past decade, improving the performance and accuracy of medical image registration has been a driving

    E-Print Network [OSTI]

    Bhattacharyya, Shuvra S.

    technologies have enabled diagnoses and procedures simply not possible a decade ago. The increasing acquisition emission tomography (PET), magnetic resonance (MRI), ultrasound (US), etc.) and the sheer volume of data registration. Image registration is the process of fusing two images such that the features in one image

  15. Development of Nuclear Magnetic Resonance Imaging/spectroscopy for improved petroleum recovery. Final report

    SciTech Connect (OSTI)

    Barrufet, M.A.; Flumerfelt, F.W.; Walsh, M.P.; Watson, A.T.

    1994-04-01

    The overall objectives of this program are to develop and apply Nuclear Magnetic Resonance Imaging (NMRI) and CT X-Ray Scanning methods for determining rock, fluid, and petrophysical properties and for fundamental studies of multiphase flow behavior in porous media. Specific objectives are divided into four subtasks: (1) development of NMRI and CT scanning for the determination of rock-fluid and petrophysical properties; (2) development of NMRI and CT scanning for characterizing conventional multiphase displacement processes; (3) development of NMR and CT scanning for characterizing dispersed phase processes; and (4) miscible displacement studies.

  16. Magnetic Resonance - Ultrasound Fusion of the Prostate: Imaging for Cancer Diagnosis

    E-Print Network [OSTI]

    Natarajan, Shyam

    2012-01-01

    fusion for prostate brachytherapy. Preliminary results,”Mri/trus data fusion for brachytherapy,” The Interna- tionalapplications in prostrate brachytherapy: analysis of phantom

  17. SU-E-T-225: It Is Necessary to Contouring the Brainstem On MRI Images in Radiotherapy of Head and Neck Cancer

    SciTech Connect (OSTI)

    Gong, G; Liu, C; Liu, C

    2014-06-01

    Purpose: To analyze the error in contouring the brainstem for patients with head and neck cancer who underwent radiotherapy based on computed tomography (CT) and magnetic resonance (MR) images. Methods: 20 brain tumor and 17 nasopharyngeal cancer patients were randomly selected. Each patient underwent MR and CT scanning. For each patient, one observer contoured the brainstem on CT and MR images for 10 times, and 10 observers from five centers delineated the brainstem on CT and MR images only one time. The inter- and intra-observers volume and outline variations were compared. Results: The volumes of brainstem contoured by inter- and intra-observers on CT and MR images were similar (p>0.05). The reproducibility of contouring brainstem on MR images was better than that on CT images (p<0.05) for both inter- and intra-observer variability. The inter- and intra-observer for contouring on CT images reached mean values of 0.81±0.05 (p>0.05) and of 0.85±0.05 (p>0.05), respectively, while on MR images these respective values were 0.90±0.05 (p>0.05) and 0.92±0.04 (p>0.05). Conclusion: Contouring the brainstem on MR images was more accurate and reproducible than that on CT images. Precise information might be more helpful for protecting the brainstem radiation injury the patients whose lesion were closed to brainstem.

  18. Image-Based Monitoring of Magnetic Resonance-Guided Thermoablative Therapies for Liver Tumors

    SciTech Connect (OSTI)

    Rempp, Hansjoerg, E-mail: hansjoerg.rempp@med.uni-tuebingen.de; Clasen, Stephan [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Pereira, Philippe L. [SLK-Kliniken, Clinic for Radiology, Nuclear Medicine, and Minimal Invasive Therapies (Germany)

    2012-12-15

    Minimally invasive treatment options for liver tumor therapy have been increasingly used during the last decade because their benefit has been proven for primary and inoperable secondary liver tumors. Among these, radiofrequency ablation has gained widespread consideration. Optimal image-guidance offers precise anatomical information, helps to position interventional devices, and allows for differentiation between already-treated and remaining tumor tissue. Patient safety and complete ablation of the entire tumor are the overriding objectives of tumor ablation. These may be achieved most elegantly with magnetic resonance (MR)-guided therapy, where monitoring can be performed based on precise soft-tissue imaging and additional components, such as diffusion-weighted imaging and temperature mapping. New MR scanner types and newly developed sequence techniques have enabled MR-guided intervention to move beyond the experimental phase. This article reviews the current role of MR imaging in guiding radiofrequency ablation. Signal characteristics of primary and secondary liver tumors are identified, and signal alteration during therapy is described. Diffusion-weighted imaging (DWI) and temperature mapping as special components of MR therapy monitoring are introduced. Practical information concerning coils, sequence selection, and parameters, as well as sequence gating, is given. In addition, sources of artifacts are identified and techniques to decrease them are introduced, and the characteristic signs of residual tumor in T1-, T2-, and DWI are described. We hope to enable the reader to choose MR sequences that allow optimal therapy monitoring depending on the initial signal characteristics of the tumor as well as its size and location in the liver.

  19. Simulation of High-Resolution Magnetic Resonance Images on the IBM Blue Gene/L Supercomputer Using SIMRI

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Baum, K. G.; Menezes, G.; Helguera, M.

    2011-01-01

    Medical imaging system simulators are tools that provide a means to evaluate system architecture and create artificial image sets that are appropriate for specific applications. We have modified SIMRI, a Bloch equation-based magnetic resonance image simulator, in order to successfully generate high-resolution 3D MR images of the Montreal brain phantom using Blue Gene/L systems. Results show that redistribution of the workload allows an anatomically accurate 256 3 voxel spin-echo simulation in less than 5 hours when executed on an 8192-node partition of a Blue Gene/L system.

  20. Diffusion-Weighted Magnetic Resonance Imaging in Monitoring Rectal Cancer Response to Neoadjuvant Chemoradiotherapy

    SciTech Connect (OSTI)

    Barbaro, Brunella; Vitale, Renata; Valentini, Vincenzo; Illuminati, Sonia; Vecchio, Fabio M.; Rizzo, Gianluca; Gambacorta, Maria Antonietta; Coco, Claudio; Crucitti, Antonio; Persiani, Roberto; Sofo, Luigi; Bonomo, Lorenzo

    2012-06-01

    Purpose: To prospectively monitor the response in patients with locally advanced nonmucinous rectal cancer after chemoradiotherapy (CRT) using diffusion-weighted magnetic resonance imaging. The histopathologic finding was the reference standard. Methods and Materials: The institutional review board approved the present study. A total of 62 patients (43 men and 19 women; mean age, 64 years; range, 28-83) provided informed consent. T{sub 2}- and diffusion-weighted magnetic resonance imaging scans (b value, 0 and 1,000 mm{sup 2}/s) were acquired before, during (mean 12 days), and 6-8 weeks after CRT. We compared the median apparent diffusion coefficients (ADCs) between responders and nonresponders and examined the associations with the Mandard tumor regression grade (TRG). The postoperative nodal status (ypN) was evaluated. The Mann-Whitney/Wilcoxon two-sample test was used to evaluate the relationships among the pretherapy ADCs, extramural vascular invasion, early percentage of increases in ADCs, and preoperative ADCs. Results: Low pretreatment ADCs (<1.0 Multiplication-Sign 10{sup -3}mm{sup 2}/s) were correlated with TRG 4 scores (p = .0011) and associated to extramural vascular invasion with ypN+ (85.7% positive predictive value for ypN+). During treatment, the mean percentage of increase in tumor ADC was significantly greater in the responders than in the nonresponders (p < .0001) and a >23% ADC increase had a 96.3% negative predictive value for TRG 4. In 9 of 16 complete responders, CRT-related tumor downsizing prevented ADC evaluations. The preoperative ADCs were significantly different (p = .0012) between the patients with and without downstaging (preoperative ADC {>=}1.4 Multiplication-Sign 10{sup -3}mm{sup 2}/s showed a positive and negative predictive value of 78.9% and 61.8%, respectively, for response assessment). The TRG 1 and TRG 2-4 groups were not significantly different. Conclusion: Diffusion-weighted magnetic resonance imaging seems to be a promising tool for monitoring the response to CRT.

  1. 3D Harmonic Mapping and Tetrahedral Meshing of Brain Imaging Data

    E-Print Network [OSTI]

    Thompson, Paul

    3D Harmonic Mapping and Tetrahedral Meshing of Brain Imaging Data Yalin Wang1 , Xianfeng Gu2 , Paul algorithm finds a harmonic map from a 3-manifold to a 3D solid sphere and the second is a novel sphere of magnetic resonance images (MRI). A heat flow method is used to solve the volumetric harmonic mapping

  2. Isotopic imaging via nuclear resonance fluorescence with laser-based Thomson radiation

    DOE Patents [OSTI]

    Barty, Christopher P. J. (Hayward, CA); Hartemann, Frederic V. (San Ramon, CA); McNabb, Dennis P. (Alameda, CA); Pruet, Jason A. (Brentwood, CA)

    2009-07-21

    The present invention utilizes novel laser-based, high-brightness, high-spatial-resolution, pencil-beam sources of spectrally pure hard x-ray and gamma-ray radiation to induce resonant scattering in specific nuclei, i.e., nuclear resonance fluorescence. By monitoring such fluorescence as a function of beam position, it is possible to image in either two dimensions or three dimensions, the position and concentration of individual isotopes in a specific material configuration. Such methods of the present invention material identification, spatial resolution of material location and ability to locate and identify materials shielded by other materials, such as, for example, behind a lead wall. The foundation of the present invention is the generation of quasimonochromatic high-energy x-ray (100's of keV) and gamma-ray (greater than about 1 MeV) radiation via the collision of intense laser pulses from relativistic electrons. Such a process as utilized herein, i.e., Thomson scattering or inverse-Compton scattering, produces beams having diameters from about 1 micron to about 100 microns of high-energy photons with a bandwidth of .DELTA.E/E of approximately 10E.sup.-3.

  3. Squid detected NMR and MRI at ultralow fields

    DOE Patents [OSTI]

    Clarke, John (Berkeley, CA); Pines, Alexander (Berkeley, CA); McDermott, Robert F. (Monona, WI); Trabesinger, Andreas H. (London, GB)

    2008-12-16

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  4. SQUID detected NMR and MRI at ultralow fields

    DOE Patents [OSTI]

    Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

    2006-10-03

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  5. Squid detected NMR and MRI at ultralow fields

    DOE Patents [OSTI]

    Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

    2006-05-30

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  6. Squid detected NMR and MRI at ultralow fields

    DOE Patents [OSTI]

    Clarke, John (Berkeley, CA); McDermott, Robert (Louisville, CO); Pines, Alexander (Berkeley, CA); Trabesinger, Andreas Heinz (CH-8006 Zurich, CH)

    2007-05-15

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  7. Engineered metalloproteins as contrast sensors for molecular fMRI

    E-Print Network [OSTI]

    Lelyveld, Victor S

    2010-01-01

    Functional brain imaging technologies seek to expand our understanding of intact neural systems. Present day functional MRI (fMRI) measures the delayed hemodynamic response that is indirectly associated with neural activity. ...

  8. Analysis, design, and application of circularly polarized RF receiver antennas for magnetic resonance imaging 

    E-Print Network [OSTI]

    Usey, Michael Christopher

    1995-01-01

    This thesis will develop methods for analyzing CP receiver coils for use in MRI. In addition, background, theory, and modeling information will be discussed in this thesis. Coil designs and implementations will be extensively described. Afterwards...

  9. MRI of Heterogeneous Hydrogenation Reactions Using Parahydrogen Polarization

    SciTech Connect (OSTI)

    Burt, Scott R; Burt, Scott R.

    2008-06-25

    The power of magnetic resonance imaging (MRI) is its ability to image the internal structure of optically opaque samples and provide detailed maps of a variety of important parameters, such as density, diffusion, velocity and temperature. However, one of the fundamental limitations of this technique is its inherent low sensitivity. For example, the low signal to noise ratio (SNR) is particularly problematic for imaging gases in porous materials due to the low density of the gas and the large volume occluded by the porous material. This is unfortunate, as many industrially relevant chemical reactions take place at gas-surface interfaces in porous media, such as packed catalyst beds. Because of this severe SNR problem, many techniques have been developed to directly increase the signal strength. These techniques work by manipulating the nuclear spin populations to produce polarized} (i.e., non-equilibrium) states with resulting signal strengths that are orders of magnitude larger than those available at thermal equilibrium. This dissertation is concerned with an extension of a polarization technique based on the properties of parahydrogen. Specifically, I report on the novel use of heterogeneous catalysis to produce parahydrogen induced polarization and applications of this new technique to gas phase MRI and the characterization of micro-reactors. First, I provide an overview of nuclear magnetic resonance (NMR) and how parahydrogen is used to improve the SNR of the NMR signal. I then present experimental results demonstrating that it is possible to use heterogeneous catalysis to produce parahydrogen-induced polarization. These results are extended to imaging void spaces using a parahydrogen polarized gas. In the second half of this dissertation, I demonstrate the use of parahydrogen-polarized gas-phase MRI for characterizing catalytic microreactors. Specifically, I show how the improved SNR allows one to map parameters important for characterizing the heat and mass transport in a heterogeneous catalyst bed. This is followed by appendices containing detailed information regarding the design and use of my experimental setup.

  10. Identification of breast contour for nipple segmentation in breast magnetic resonance images

    SciTech Connect (OSTI)

    Gwo, Chih-Ying [Department of Information Management, Chien Hsin University of Science and Technology, Taoyuan 320, Taiwan (China)] [Department of Information Management, Chien Hsin University of Science and Technology, Taoyuan 320, Taiwan (China); Gwo, Allen [Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712 (United States)] [Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712 (United States); Wei, Chia-Hung, E-mail: rogerwei@uch.edu.tw [Department of Information Management, Chien Hsin University of Science and Technology, Taoyuan 320, Taiwan and Graduate Institute of Biomedical Informatics, Taipei Medical University, Taipei 110, Taiwan (China)] [Department of Information Management, Chien Hsin University of Science and Technology, Taoyuan 320, Taiwan and Graduate Institute of Biomedical Informatics, Taipei Medical University, Taipei 110, Taiwan (China); Huang, Pai Jung [Graduate Institute of Biomedical Informatics, Taipei Medical University, Taipei 110, Taiwan and Comprehensive Breast Health Center, Taipei Medical University Hospital, Taipei 110, Taiwan (China)] [Graduate Institute of Biomedical Informatics, Taipei Medical University, Taipei 110, Taiwan and Comprehensive Breast Health Center, Taipei Medical University Hospital, Taipei 110, Taiwan (China)

    2014-02-15

    Purpose: The purpose of this study is to develop a method to simulate the breast contour and segment the nipple in breast magnetic resonance images. Methods: This study first identifies the chest wall and removes the chest part from the breast MR images. Subsequently, the cleavage and its motion artifacts are removed, distinguishing the separate breasts, where the edge points are sampled for curve fitting. Next, a region growing method is applied to find the potential nipple region. Finally, the potential nipple region above the simulated curve can be removed in order to retain the original smooth contour. Results: The simulation methods can achieve the least root mean square error (RMSE) for certain cases. The proposed YBnd and (Dmin+Dmax)/2 methods are significant due toP = 0.000. The breast contour curve detected by the two proposed methods is closer than that determined by the edge detection method. The (Dmin+Dmax)/2 method can achieve the lowest RMSE of 1.1029 on average, while the edge detection method results in the highest RMSE of 6.5655. This is only slighter better than the comparison methods, which implies that the performance of these methods depends upon the conditions of the cases themselves. Under this method, the maximal Dice coefficient is 0.881, and the centroid difference is 0.36 pixels. Conclusions: The contributions of this study are twofold. First, a method was proposed to identify and segment the nipple in breast MR images. Second, a curve-fitting method was used to simulate the breast contour, allowing the breast to retain its original smooth shape.

  11. NMR and MRI apparatus and method

    DOE Patents [OSTI]

    Clarke, John; Kelso, Nathan; Lee, SeungKyun; Moessle, Michael; Myers, Whittier; McDermott, Robert; ten Haken, Bernard; Pines, Alexander; Trabesinger, Andreas

    2007-03-06

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. Additional signal to noise benefits are obtained by use of a low noise polarization coil, comprising litz wire or superconducting materials. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  12. Imaging Agents DOI: 10.1002/anie.201301135

    E-Print Network [OSTI]

    Gao, Jinming

    Takahashi, A. Dean Sherry, and Jinming Gao* Magnetic resonance imaging (MRI) is a powerful non- invasive a "reverse" pH gradient across the cell membrane is observed in cancer cells compared to normal cells.[11 19 F signal. b) Structural formula of three representative diblock copolymers containing different p

  13. Rf coil design for multi-frequency magnetic resonance imaging & spectroscopy 

    E-Print Network [OSTI]

    Dabirzadeh, Arash

    2009-05-15

    Magnetic Resonance Spectroscopy is known as a valuable diagnostic tool for physicians as well as a research tool for biochemists. In addition to hydrogen (which is the most abundant atom with nuclear magnetic resonance capability), other species...

  14. Multimodality Image Fusion-Guided Procedures: Technique, Accuracy, and Applications

    SciTech Connect (OSTI)

    Abi-Jaoudeh, Nadine, E-mail: naj@mail.nih.gov [National Institutes of Health, Radiology and Imaging Sciences (United States); Kruecker, Jochen, E-mail: jochen.kruecker@philips.com [Philips Research North America (United States); Kadoury, Samuel, E-mail: samuel.kadoury@polymtl.ca [Ecole Polytechnique de Montreal, Department of Computer and Software Engineering, Institute of Biomedical Engineering (Canada); Kobeiter, Hicham, E-mail: hicham.kobeiter@gmail.com [CHU Henri Mondor, UPEC, Departments of Radiology and d'imagrie medicale (France); Venkatesan, Aradhana M., E-mail: VenkatesanA@cc.nih.gov; Levy, Elliot, E-mail: levyeb@cc.nih.gov; Wood, Bradford J., E-mail: bwood@cc.nih.gov [National Institutes of Health, Radiology and Imaging Sciences (United States)

    2012-10-15

    Personalized therapies play an increasingly critical role in cancer care: Image guidance with multimodality image fusion facilitates the targeting of specific tissue for tissue characterization and plays a role in drug discovery and optimization of tailored therapies. Positron-emission tomography (PET), magnetic resonance imaging (MRI), and contrast-enhanced computed tomography (CT) may offer additional information not otherwise available to the operator during minimally invasive image-guided procedures, such as biopsy and ablation. With use of multimodality image fusion for image-guided interventions, navigation with advanced modalities does not require the physical presence of the PET, MRI, or CT imaging system. Several commercially available methods of image-fusion and device navigation are reviewed along with an explanation of common tracking hardware and software. An overview of current clinical applications for multimodality navigation is provided.

  15. Discovery Radiomics for Multi-Parametric MRI Prostate Cancer Detection

    E-Print Network [OSTI]

    Chung, Audrey G; Kumar, Devinder; Khalvati, Farzad; Haider, Masoom A; Wong, Alexander

    2015-01-01

    Prostate cancer is the most diagnosed form of cancer in Canadian men, and is the third leading cause of cancer death. Despite these statistics, prognosis is relatively good with a sufficiently early diagnosis, making fast and reliable prostate cancer detection crucial. As imaging-based prostate cancer screening, such as magnetic resonance imaging (MRI), requires an experienced medical professional to extensively review the data and perform a diagnosis, radiomics-driven methods help streamline the process and has the potential to significantly improve diagnostic accuracy and efficiency, and thus improving patient survival rates. These radiomics-driven methods currently rely on hand-crafted sets of quantitative imaging-based features, which are selected manually and can limit their ability to fully characterize unique prostate cancer tumour phenotype. In this study, we propose a novel \\textit{discovery radiomics} framework for generating custom radiomic sequences tailored for prostate cancer detection. Discover...

  16. Evaluation of Artifacts and Distortions of Titanium Applicators on 3.0-Tesla MRI: Feasibility of Titanium Applicators in MRI-Guided Brachytherapy for Gynecological Cancer

    SciTech Connect (OSTI)

    Kim, Yusung, E-mail: yusung-kim@uiowa.edu [Department of Radiation Oncology, University of Iowa, Iowa City, IA (United States); Muruganandham, Manickam; Modrick, Joseph M.; Bayouth, John E. [Department of Radiation Oncology, University of Iowa, Iowa City, IA (United States)

    2011-07-01

    Purpose: The aim of this study was to characterize the levels of artifacts and distortions of titanium applicators on 3.0-Tesla magnetic resonance imaging (MRI). Methods and Materials: Fletcher-Suit-Delclos-style tandem and ovoids (T and O) and tandem and ring applicator (T and R) were examined. The quality assurance (QA) phantoms for each applicator were designed and filled with copper sulphate solution (1.5 g/l). The artifacts were quantified with the registration of corresponding computed tomography (CT) images. A favorable MR sequence was searched in terms of artifacts. Using the sequence, the artifacts were determined. The geometric distortions induced by the applicators were quantified through each registration of CT and MRI without applicators. The artifacts of T and O were also evaluated on in vivo MRI datasets of 5 patients. Results: T1-weighted MRI with 1-mm slice thickness was found as a favorable MR sequence. Applying the sequence, the artifacts at the tandem tip of T and O and T and R were determined as 1.5 {+-} 0.5 mm in a superior direction in phantom studies. In the ovoids of T and O, we found artifacts less than 1.5 {+-} 0.5 mm. The artifacts of a T and O tandem in vivo were found as less than 2.6 {+-} 1.3 mm on T1-weighted MRI, whereas less than 6.9 {+-} 3.4 mm on T2-weighted MRI. No more than 1.2 {+-} 0.6 mm (3.0 {+-} 1.5 mm) of distortions, due to a titanium applicator, were measured on T1-weighted MRI (T2-). Conclusion: In 3.0-Tesla MRI, we found the artifact widths at the tip of tandem were less than 1.5 {+-} 0.5 mm for both T and O and T and R when using T1-weighted MRI in phantom studies. However, exclusive 3.0-Tesla MRI-guided brachytherapy planning with a titanium applicator should be cautiously implemented.

  17. Magnetic Resonance Imaging of Therapy-Induced Necrosis Using Gadolinium-Chelated Polyglutamic Acids

    SciTech Connect (OSTI)

    Jackson, Edward F.; Esparza-Coss, Emilio; Wen Xiaoxia; Ng, Chaan S.; Daniel, Sherita L.; Price, Roger E.; Rivera, Belinda; Charnsangavej, Chusilp; Gelovani, Juri G.; Li Chun . E-mail: cli@di.mdacc.tmc.edu

    2007-07-01

    Purpose: Necrosis is the most common morphologic alteration found in tumors and surrounding normal tissues after radiation therapy or chemotherapy. Accurate measurement of necrosis may provide an early indication of treatment efficacy or associated toxicity. The purpose of this report is to evaluate the selective accumulation of polymeric paramagnetic magnetic resonance (MR) contrast agents-gadolinium p-aminobenzyl-diethylenetriaminepentaacetic acid-poly(glutamic acid) (L-PG-DTPA-Gd and D-PG-DTPA-Gd)-in necrotic tissue. Methods and Materials: Two different solid tumor models, human Colo-205 xenograft and syngeneic murine OCA-1 ovarian tumors, were used in this study. Necrotic response was induced by treatment with poly(L-glutamic acid)-paclitaxel conjugate (PG-TXL). T{sub 1}-weighted spin-echo images were obtained immediately and up to 4 days after contrast injection and compared with corresponding histologic specimens. Two low-molecular-weight contrast agents, DTPA-Gd and oligomeric(L-glutamic acid)-DTPA-Gd, were used as nonspecific controls. Results: Initially, there was minimal tumor enhancement after injection of either L-PG-DTPA-Gd or D-PG-DTPA-Gd, but rapid enhancement after injection of low-molecular-weight agents. However, polymeric contrast agents, but not low-molecular-weight contrast agents, caused sustained enhancement in regions of tumor necrosis in both tumors treated with PG-TXL and untreated tumors. These data indicate that high molecular weight, rather than in vivo biodegradation, is necessary for the specific localization of polymeric MR contrast agents to necrotic tissue. Moreover, biotinylated L-PG-DTPA-Gd colocalized with macrophages in the tumor necrotic areas, suggesting that selective accumulation of L- and D-PG-DTPA-Gd in necrotic tissue was mediated through residing macrophages. Conclusions: Our data suggest that MR imaging with PG-DTPA-Gd may be a useful technique for noninvasive characterization of treatment-induced necrosis.

  18. Evaluation of Angiographic and Technical Aspects of Carotid Stenting with Diffusion-Weighted Magnetic Resonance Imaging

    SciTech Connect (OSTI)

    Blasel, Stella, E-mail: Stella.Blasel@kgu.de; Hattingen, Elke; Berkefeld, Joachim; Kurre, Wiebke [University of Frankfurt, Institute of Neuroradiology (Germany); Morawe, Gerald [University of Frankfurt, Department of Biomathematics (Germany); Zanella, Friedhelm; Rochemont, Richard Du Mesnil de [University of Frankfurt, Institute of Neuroradiology (Germany)

    2009-07-15

    The detection of clinically silent ischemic lesions on postprocedural diffusion-weighted magnetic resonance images has become a preferred method for the description of embolic risks. The purpose of this single-center study was to evaluate whether diffusion-weighted imaging (DWI) could determine material related or technical risk factors of filter-protected carotid stenting. Eighty-four patients with symptomatic severe ({>=}60%) carotid artery stenoses received filter-protected carotid stenting. Standard DWI (b = 1000) was performed within 48 h before and after carotid stenting. The occurrence and load of new postinterventional DWI lesions were assessed. Multivariate analysis was performed to determine risk factors associated with DWI lesions, with emphasis on technical factors such as use of different access devices (guiding catheter method vs. long carotid sheath method), type of stent (open-cell nitinol stent vs. closed-cell Wallstent), and protective device (filters with 80-{mu}m vs. 110-120-{mu}m pore size). Markers for generalized atherosclerosis and for degree and site of stenosis were assessed to allow comparison of adequate risk profiles. Access, protective device, and stent type were not significantly associated with new embolic DWI lesions when we compared patients with equivalent risk profiles (long carotid sheath method 48% [11 of 23] vs. guiding catheter method 44% [27 of 61], Wallstent 47% [15 of 32] vs. nitinol stent 44% [23 of 52], and small pore size filter 61% [11 of 18] vs. large pore size filter 41% [27 of 66]). Single-center DWI studies with a moderate number of cases are inadequate for proper assessment of the embolic risk of technical- or material-related risk factors in carotid stenting. Larger multicenter studies with more cases are needed.

  19. Discrete magic angle turning system, apparatus, and process for in situ magnetic resonance spectroscopy and imaging

    DOE Patents [OSTI]

    Hu, Jian Zhi (Richland, WA); Sears, Jr., Jesse A. (Kennewick, WA); Hoyt, David W. (Richland, WA); Wind, Robert A. (Kennewick, WA)

    2009-05-19

    Described are a "Discrete Magic Angle Turning" (DMAT) system, devices, and processes that combine advantages of both magic angle turning (MAT) and magic angle hopping (MAH) suitable, e.g., for in situ magnetic resonance spectroscopy and/or imaging. In an exemplary system, device, and process, samples are rotated in a clockwise direction followed by an anticlockwise direction of exactly the same amount. Rotation proceeds through an angle that is typically greater than about 240 degrees but less than or equal to about 360 degrees at constant speed for a time applicable to the evolution dimension. Back and forth rotation can be synchronized and repeated with a special radio frequency (RF) pulse sequence to produce an isotropic-anisotropic shift 2D correlation spectrum. The design permits tubes to be inserted into the sample container without introducing plumbing interferences, further allowing control over such conditions as temperature, pressure, flow conditions, and feed compositions, thus permitting true in-situ investigations to be carried out.

  20. Advanced slow-magic angle spinning probe for magnetic resonance imaging and spectroscopy

    DOE Patents [OSTI]

    Wind, Robert A.; Hu, Jian Zhi; Minard, Kevin R.; Rommereim, Donald N.

    2006-01-24

    The present invention relates to a probe and processes useful for magnetic resonance imaging and spectroscopy instruments. More particularly, the invention relates to a MR probe and processes for obtaining resolution enhancements of fluid objects, including live specimens, using an ultra-slow (magic angle) spinning (MAS) of the specimen combined with a modified phase-corrected magic angle turning (PHORMAT) pulse sequence. Proton NMR spectra were measured of the torso and the top part of the belly of a female BALBc mouse in a 2T field, while spinning the animal at a speed of 1.5 Hz. Results show that even in this relatively low field with PHORMAT, an isotropic spectrum is obtained with line widths that are a factor 4.6 smaller than those obtained in a stationary mouse. Resolution of 1H NMR metabolite spectra are thus significantly enhanced. Results indicate that PHORMAT has the potential to significantly increase the utility of 1H NMR spectroscopy for in vivo biochemical, biomedical and/or medical applications involving large-sized biological objects such as mice, rats and even humans within a hospital setting. For small-sized objects, including biological objects, such as excised tissues, organs, live bacterial cells, and biofilms, use of PASS at a spinning rate of 30 Hz and above is preferred.

  1. The Physiological Basis of BOLD Functional MRI /

    E-Print Network [OSTI]

    Griffeth, Valerie Ewing McClintock

    2013-01-01

    metabolism Detailed biophysical model of the BOLD response Functional magnetic resonance imaging Generalized calibration model General linear model Gradient

  2. Modifications in Dynamic Contrast-Enhanced Magnetic Resonance Imaging Parameters After ?-Particle-Emitting {sup 227}Th-trastuzumab Therapy of HER2-Expressing Ovarian Cancer Xenografts

    SciTech Connect (OSTI)

    Heyerdahl, Helen; Røe, Kathrine; Brevik, Ellen Mengshoel; Dahle, Jostein

    2013-09-01

    Purpose: The purpose of this study was to investigate the effect of ?-particle-emitting {sup 227}Th-trastuzumab radioimmunotherapy on tumor vasculature to increase the knowledge about the mechanisms of action of {sup 227}Th-trastuzumab. Methods and Materials: Human HER2-expressing SKOV-3 ovarian cancer xenografts were grown bilaterally in athymic nude mice. Mice with tumor volumes 253 ± 36 mm{sup 3} (mean ± SEM) were treated with a single injection of either {sup 227}Th-trastuzumab at a dose of 1000 kBq/kg body weight (treated group, n=14 tumors) or 0.9% NaCl (control group, n=10 tumors). Dynamic T1-weighted contrast-enhanced magnetic resonance imaging (DCEMRI) was used to study the effect of {sup 227}Th-trastuzumab on tumor vasculature. DCEMRI was performed before treatment and 1, 2, and 3 weeks after therapy. Tumor contrast-enhancement curves were extracted voxel by voxel and fitted to the Brix pharmacokinetic model. Pharmacokinetic parameters for the tumors that underwent radioimmunotherapy were compared with the corresponding parameters of control tumors. Results: Significant increases of k{sub ep}, the rate constant of diffusion from the extravascular extracellular space to the plasma (P<.05), and k{sub el,} the rate of clearance of contrast agent from the plasma (P<.01), were seen in the radioimmunotherapy group 2 and 3 weeks after injection, compared with the control group. The product of k{sub ep} and the amplitude parameter A, associated with increased vessel permeability and perfusion, was also significantly increased in the radioimmunotherapy group 2 and 3 weeks after injection (P<.01). Conclusions: Pharmacokinetic modeling of MRI contrast-enhancement curves evidenced significant alterations in parameters associated with increased tumor vessel permeability and tumor perfusion after {sup 227}Th-trastuzumab treatment of HER2-expressing ovarian cancer xenografts.

  3. NMR/MRI with hyperpolarized gas and high Tc SQUID

    DOE Patents [OSTI]

    Schlenga, Klaus (Eggenstein, DE); de Souza, Ricardo E. (Recife, BR); Wong-Foy, Annjoe (Berkeley, CA); Clarke, John (Berkeley, CA); Pines, Alexander (Berkeley, CA)

    2000-01-01

    A method and apparatus for the detection of nuclear magnetic resonance (NMR) signals and production of magnetic resonance imaging (MRI) from samples combines the use of hyperpolarized inert gases to enhance the NMR signals from target nuclei in a sample and a high critical temperature (Tc) superconducting quantum interference device (SQUID) to detect the NMR signals. The system operates in static magnetic fields of 3 mT or less (down to 0.1 mT), and at temperatures from liquid nitrogen (77K) to room temperature. Sample size is limited only by the size of the magnetic field coils and not by the detector. The detector is a high Tc SQUID magnetometer designed so that the SQUID detector can be very close to the sample, which can be at room temperature.

  4. Applications of Magnetic Resonance to Current Detection and Microscale Flow Imaging

    E-Print Network [OSTI]

    Halpern-Manners, Nicholas Wm

    2011-01-01

    and biomarker screening. Analytical Chemistry 78, 15 (2006),by remote detection. Analytical Chemistry 77, [96] Menon, R.resonance spectroscopy. Analytical Chemistry 79, 7 (2007),

  5. Magnetic Resonance Imaging at Princeton, UofV, and UNH | U.S...

    Office of Science (SC) Website

    supported by: NIH, NASA Impactbenefit to spin-off field: Static & dynamic imaging of lungs, heart, and possibly the brain, possible imaging of astronauts 'Hyperpolarized gas...

  6. JOB OPENINGS MRI technical developments and applications

    E-Print Network [OSTI]

    Duong, Timothy Q.

    of these innovative imaging technologies to study anatomy, metabolism, physiology (such as blood flow and oxygenation + AC88 high performance gradient insert, and 6) MRI: 3T/90cm whole-body Philips Achieva There are also

  7. Coupled Physics Inverse Problems: EIT meets MRI

    E-Print Network [OSTI]

    2013-11-14

    Nov 14, 2014 ... about 1 mm (New MRI, INUMAC (Imaging of Neuro disease Using high-field MR And Contrastophores) 11.75-Tesla resolves up to. 0.1mm).

  8. NACoM2003 Extended Abstracts 1 --6 Fast image registration --a variational approach

    E-Print Network [OSTI]

    Modersitzki, Jan

    Fischer # and Jan Modersitzki Institute of Mathematics, University of LË?ubeck, D­23560 LË?ubeck, Germany#erent modalities, like for example computer tomography (CT) and magnetic resonance imaging (MRI). To be successful measure. For this type of problems, we provide a toolbox of registration routines which enables the user

  9. MR imaging in the non-human primate: studies of function and of dynamic connectivity

    E-Print Network [OSTI]

    of Physiology of Cognitive Processes, Spemannstr 38, 72076 Tu¨ bingen, Germany e-mail: nikos.logothetis@tuebingen.mpg.de Current Opinion in Neurobiology 2003, 13:1­13 This review comes from a themed issue on New technologies extracellular field potential MRI magnetic resonance imaging MUA multiple-unit spiking activity PET positron

  10. Design and Simulation of Coils for High Field Magnetic Resonance Imaging and Spectroscopy 

    E-Print Network [OSTI]

    Rispoli, Joseph V

    2015-06-05

    The growing availability of high-field magnetic resonance (MR) scanners has reignited interest in the in vivo investigation of metabolics in the body. In particular, multinuclear MR spectroscopy (MRS) data reveal physiological details inaccessible...

  11. HST.583 Functional Magnetic Resonance Imaging: Data Acquisition and Analysis, Fall 2004

    E-Print Network [OSTI]

    Gollub, Randy L.

    Provides information relevant to the conduct and interpretation of human brain mapping studies. Provides in-depth coverage of the physics of image formation, mechanisms of image contrast, and the physiological basis for ...

  12. Resolving the Impact of Biological Processes on Water Transport in Unsaturated Porous Media Through Nuclear Magnetic Resonance Micro-Imaging

    SciTech Connect (OSTI)

    Seymour, Joseph D.

    2005-06-01

    The magnetic resonance microscopy (MRM) work at Montana State University has extended the imaging of a single biofilm in a 1 mm capillary reactor to correlate T2 magnetic relaxation maps displaying biofilm structure with the corresponding velocity patterns in three dimensions in a Staphylococcus epidermidis biofilm fouled square capillary. A square duct geometry is chosen to provide correlation with existing experiments and simulations, as research bioreactors tend to be of square or rectangular cross section for optical or microelectrode access. The spatially resolved velocity data provide details on the impact of biofilm induced advection on mass transport from the bulk fluid to the biofilm and through the capillary bioreactor.

  13. 445ISSN 1755-519110.2217/IIM.10.33 2010 Future Medicine Ltd Imaging Med. (2010) 2(4), 445457 MRI artifacts and correction strategies

    E-Print Network [OSTI]

    Southern California, University of

    2010-01-01

    . Perhaps most importantly, because it does not rely on ionizing radiation, MRI is safe for serial by a superconductive coil, one or more radiofrequency (RF) fields, and several weak magnetic fields generated by three

  14. IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 20, NO. 8, AUGUST 2001 677 Automated Segmentation of Multiple Sclerosis

    E-Print Network [OSTI]

    of Multiple Sclerosis Lesions by Model Outlier Detection Koen Van Leemput*, Frederik Maes, Dirk Vandermeulen for segmentation of multiple sclerosis (MS) lesions from multispec- tral magnetic resonance (MR) images. The method measurements. Index Terms--Digital brain atlas, MRI, multiple sclerosis, tissue classification. I. INTRODUCTION

  15. MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution conductivity imaging

    E-Print Network [OSTI]

    Eyüboðlu, Murat

    MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution are measured by using conventional electrical impedance tomography techniques and high resolution magnetic and the point spread function is not space invariant. On the other hand, magnetic field and electrical current

  16. Pulsed Gradient Spin Echo Nuclear Magnetic Resonance Imaging of Diffusion in Granular Flow

    SciTech Connect (OSTI)

    Seymour, Joseph D.; Caprihan, Arvind; Altobelli, Stephen A.; Fukushima, Eiichi

    2000-01-10

    We derive the formalism to obtain spatial distributions of collisional correlation times for macroscopic particles undergoing granular flow from pulsed gradient spin echo nuclear magnetic resonance diffusion data. This is demonstrated with an example of axial motion in the shear flow regime of a 3D granular flow in a horizontal rotating cylinder at one rotation rate. (c) 2000 The American Physical Society.

  17. Enhancement of NMR and MRI in the presence of hyperpolarized noble gases

    DOE Patents [OSTI]

    Pines, Alexander; Budinger, Thomas; Navon, Gil; Song, Yi-Qiao; Appelt, Stephan; Bifone, Angelo; Taylor, Rebecca; Goodson, Boyd; Seydoux, Roberto; Room, Toomas; Pietrass, Tanja

    2004-11-16

    The present invention relates generally to nuclear magnetic resonance (NMR) techniques for both spectroscopy and imaging. More particularly, the present invention relates to methods in which hyperpolarized noble gases (e.g., Xe and He) are used to enhance and improve NMR and MRI. Additionally, the hyperpolarized gas solutions of the invention are useful both in vitro and in vivo to study the dynamics or structure of a system. When used with biological systems, either in vivo or in vitro, it is within the scope of the invention to target the hyperpolarized gas and deliver it to specific regions within the system.

  18. Apparatus for preparing a solution of a hyperpolarized noble gas for NMR and MRI analysis

    DOE Patents [OSTI]

    Pines, Alexander (Berkeley, CA); Budinger, Thomas (Berkeley, CA); Navon, Gil (Ramat Gan, IL); Song, Yi-Qiao (Berkeley, CA); Appelt, Stephan (Waiblingen, DE); Bifone, Angelo (Rome, IT); Taylor, Rebecca (Berkeley, CA); Goodson, Boyd (Berkeley, CA); Seydoux, Roberto (Berkeley, CA); Room, Toomas (Albany, CA); Pietrass, Tanja (Socorro, NM)

    2008-06-10

    The present invention relates generally to nuclear magnetic resonance (NMR) techniques for both spectroscopy and imaging. More particularly, the present invention relates to methods in which hyperpolarized noble gases (e.g., Xe and He) are used to enhance and improve NMR and MRI. Additionally, the hyperpolarized gas solutions of the invention are useful both in vitro and in vivo to study the dynamics or structure of a system. When used with biological systems, either in vivo or in vitro, it is within the scope of the invention to target the hyperpolarized gas and deliver it to specific regions within the system.

  19. Method for nuclear magnetic resonance imaging using deuterum as a contrast agent

    DOE Patents [OSTI]

    Kehayias, Joseph J. (Chestnut Hill, MA); Joel, Darrel D. (Setauket, NY); Adams, William H. (Eastport, NY); Stein, Harry L. (Glen Head, NY)

    1990-01-01

    A method for in vivo NMR imaging of the blood vessels and organs of a patient characterized by using a dark dye-like imaging substance consisting essentially of a stable, high-purity concentration of D.sub.2 O in a solution with water.

  20. A New Approach to Lung Image Segmentation using Fuzzy Possibilistic C-Means Algorithm

    E-Print Network [OSTI]

    Gomathi, M

    2010-01-01

    Image segmentation is a vital part of image processing. Segmentation has its application widespread in the field of medical images in order to diagnose curious diseases. The same medical images can be segmented manually. But the accuracy of image segmentation using the segmentation algorithms is more when compared with the manual segmentation. In the field of medical diagnosis an extensive diversity of imaging techniques is presently available, such as radiography, computed tomography (CT) and magnetic resonance imaging (MRI). Medical image segmentation is an essential step for most consequent image analysis tasks. Although the original FCM algorithm yields good results for segmenting noise free images, it fails to segment images corrupted by noise, outliers and other imaging artifact. This paper presents an image segmentation approach using Modified Fuzzy C-Means (FCM) algorithm and Fuzzy Possibilistic c-means algorithm (FPCM). This approach is a generalized version of standard Fuzzy CMeans Clustering (FCM) ...

  1. Cost Effective Open Geometry HTS MRI System amended to BSCCO 2212 Wire for High Field Magnets

    SciTech Connect (OSTI)

    Kennth Marken

    2006-08-11

    The original goal of this Phase II Superconductivity Partnership Initiative project was to build and operate a prototype Magnetic Resonance Imaging (MRI) system using high temperature superconductor (HTS) coils wound from continuously processed dip-coated BSCCO 2212 tape conductor. Using dip-coated tape, the plan was for MRI magnet coils to be wound to fit an established commercial open geometry, 0.2 Tesla permanent magnet system. New electronics and imaging software for a prototype higher field superconducting system would have added significantly to the cost. However, the use of the 0.2 T platform would allow the technical feasibility and the cost issues for HTS systems to be fully established. Also it would establish the energy efficiency and savings of HTS open MRI compared with resistive and permanent magnet systems. The commercial goal was an open geometry HTS MRI running at 0.5 T and 20 K. This low field open magnet was using resistive normal metal conductor and its heat loss was rather high around 15 kolwatts. It was expected that an HTS magnet would dissipate around 1 watt, significantly reduce power consumption. The SPI team assembled to achieve this goal was led by Oxford Instruments, Superconducting Technology (OST), who developed the method of producing commercial dip coated tape. Superconductive Components Inc. (SCI), a leading US supplier of HTS powders, supported the conductor optimization through powder optimization, scaling, and cost reduction. Oxford Magnet Technology (OMT), a joint venture between Oxford Instruments and Siemens and the world’s leading supplier of MRI magnet systems, was involved to design and build the HTS MRI magnet and cryogenics. Siemens Magnetic Resonance Division, a leading developer and supplier of complete MRI imaging systems, was expected to integrate the final system and perform imaging trials. The original MRI demonstration project was ended in July 2004 by mutual consent of Oxford Instruments and Siemens. Between the project start and that date a substantial shift in the MRI marketplace occurred, with rapid growth for systems at higher fields (1.5 T and above) and a consequent decline in the low field market (<1.0 T). While the project aim appeared technically attainable at that time, the conclusion was reached that the system and market economics do not warrant additional investment. The program was redirected to develop BSCCO 2212 multifilament wire development for high field superconducting magnets for NMR and other scientific research upon an agreement between DOE and Oxford Instruments, Superconducting Technology. The work t took place between September, 2004 and the project end in early 2006 was focused on 2212 multifilamentary wire. This report summarizes the technical achievements both in 2212 dip coated for an HTS MRI system and in BSCCO 2212 multifilamentary wire for high field magnets.

  2. Mapping local hippocampal changes in Alzheimer's disease and normal ageing with MRI at 3 Tesla

    E-Print Network [OSTI]

    Thompson, Paul

    Mapping local hippocampal changes in Alzheimer's disease and normal ageing with MRI at 3 Tesla and Alzheimer's disease based on high resolution MRI at 3 Tesla. T1-weighted images were acquired from 19

  3. Nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOE Patents [OSTI]

    Fukushima, Eiichi (Los Alamos, NM); Roeder, Stephen B. W. (La Mesa, CA); Assink, Roger A. (Albuquerque, NM); Gibson, Atholl A. V. (Bryan, TX)

    1986-01-01

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio-frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  4. Clinical Evaluation of Stereotactic Target Localization Using 3-Tesla MRI for Radiosurgery Planning

    SciTech Connect (OSTI)

    MacFadden, Derek [University of Toronto Faculty of Medicine, Toronto, ON (Canada); Zhang Beibei; Brock, Kristy K. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Hodaie, Mojgan [Division of Neurosurgery, Toronto Western Hospital, Toronto, ON (Canada); Laperriere, Normand [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Schwartz, Michael [Division of Neurosurgery, Toronto Western Hospital, Toronto, ON (Canada); Tsao, May [Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Department of Radiation Oncology, Sunnybrook Regional Cancer Centre, Toronto, ON (Canada); Stainsby, Jeffrey [Applied Science Laboratories, GE Healthcare, Mississauga, ON (Canada); Lockwood, Gina [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Mikulis, David [Department of Medical Imaging, University Health Network, Toronto, ON (Canada); Menard, Cynthia, E-mail: cynthia.menard@rmp.uhn.on.c [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada)

    2010-04-15

    Purpose: Increasing the magnetic resonance imaging (MRI) field strength can improve image resolution and quality, but concerns remain regarding the influence on geometric fidelity. The objectives of the present study were to spatially investigate the effect of 3-Tesla (3T) MRI on clinical target localization for stereotactic radiosurgery. Methods and Materials: A total of 39 patients were enrolled in a research ethics board-approved prospective clinical trial. Imaging (1.5T and 3T MRI and computed tomography) was performed after stereotactic frame placement. Stereotactic target localization at 1.5T vs. 3T was retrospectively analyzed in a representative cohort of patients with tumor (n = 4) and functional (n = 5) radiosurgical targets. The spatial congruency of the tumor gross target volumes was determined by the mean discrepancy between the average gross target volume surfaces at 1.5T and 3T. Reproducibility was assessed by the displacement from an averaged surface and volume congruency. Spatial congruency and the reproducibility of functional radiosurgical targets was determined by comparing the mean and standard deviation of the isocenter coordinates. Results: Overall, the mean absolute discrepancy across all patients was 0.67 mm (95% confidence interval, 0.51-0.83), significantly <1 mm (p < .010). No differences were found in the overall interuser target volume congruence (mean, 84% for 1.5T vs. 84% for 3T, p > .4), and the gross target volume surface mean displacements were similar within and between users. The overall average isocenter coordinate discrepancy for the functional targets at 1.5T and 3T was 0.33 mm (95% confidence interval, 0.20-0.48), with no patient-specific differences between the mean values (p >.2) or standard deviations (p >.1). Conclusion: Our results have provided clinically relevant evidence supporting the spatial validity of 3T MRI for use in stereotactic radiosurgery under the imaging conditions used.

  5. Bioengineered Probes for Molecular Magnetic Resonance Imaging in the Nervous System

    E-Print Network [OSTI]

    Hsieh, Vivian

    The development of molecular imaging probes has changed the nature of neurobiological research. Some of the most notable successes have involved the use of biological engineering techniques for the creation of fluorescent ...

  6. Phase-Contrast MRI and CFD Modeling of Apparent 3He Gas Flow in Rat Pulmonary Airways

    SciTech Connect (OSTI)

    Minard, Kevin R.; Kuprat, Andrew P.; Kabilan, Senthil; Jacob, Rick E.; Einstein, Daniel R.; Carson, James P.; Corley, Richard A.

    2012-08-01

    Phase-contrast (PC) magnetic resonance imaging (MRI) with hyperpolarized 3He is potentially useful for developing and testing patient-specific models of pulmonary airflow. One challenge, however, is that PC-MRI provides apparent values of local 3He velocity that not only depend on actual airflow but also on gas diffusion. This not only blurs laminar flow patterns in narrow airways but also introduces anomalous airflow structure that reflects gas-wall interactions. Here, both effects are predicted in a live rat using computational fluid dynamics (CFD), and for the first time, simulated patterns of apparent 3He gas velocity are compared with in-vivo PC-MRI. Results show (1) that correlations (R2) between measured and simulated airflow patterns increase from 0.23 to 0.79 simply by accounting for apparent 3He transport, and that (2) remaining differences are mainly due to uncertain airway segmentation and partial volume effects stemming from relatively coarse MRI resolution. Higher-fidelity testing of pulmonary airflow predictions should therefore be possible with future imaging improvements.

  7. A 16-Channel Receive Array Insert for Magnetic Resonance Imaging of the Breast at 7T 

    E-Print Network [OSTI]

    By, Samantha

    2014-04-01

    , this will enable the ability to acquire images with higher resolution than could be achieved at 3T or 1.5T in clinically standard scan times. This has the potential to improve the morphological characterization of tumors and their involvement in the surrounding...

  8. Development of a 0.014-inch Magnetic Resonance Imaging Guidewire

    E-Print Network [OSTI]

    Atalar, Ergin

    . The conductors were made of superelastic, nonmagnetic, biocompatible mate- rials, Nitinol or MP35N. Then, such as balloon angioplasty and stent placement (4). Currently, the MR imaging-guidewire is made of Nitinol, 0 can construct a 0.014-inch MRIG with superelastic materials, such as Nitinol and MP35N, similar

  9. A novel electron gun for inline MRI-linac configurations

    SciTech Connect (OSTI)

    Constantin, Drago? E. Fahrig, Rebecca; Holloway, Lois; Keall, Paul J.

    2014-02-15

    Purpose: This work introduces a new electron gun geometry capable of robust functioning in the presence of a high strength external magnetic field for axisymmetric magnetic resonance imaging (MRI)-linac configurations. This allows an inline MRI-linac to operate without the need to isolate the linear accelerator (linac) using a magnetic shield. This MRI-linac integration approach not only leaves the magnet homogeneity unchanged but also provides the linac flexibility to move along the magnet axis of symmetry if the source to target distance needs to be adjusted. Methods: Simple electron gun geometry modifications of a Varian 600C electron gun are considered and solved in the presence of an external magnetic field in order to determine a set of design principles for the new geometry. Based on these results, a new gun geometry is proposed and optimized in the fringe field of a 0.5 T open bore MRI magnet (GE Signa SP). A computer model for the 6 MeV Varian 600C linac is used to determine the capture efficiency of the new electron gun-linac system in the presence of the fringe field of the same MRI scanner. The behavior of the new electron gun plus the linac system is also studied in the fringe fields of two other magnets, a 1.0 T prototype open bore magnet and a 1.5 T GE Conquest scanner. Results: Simple geometrical modifications of the original electron gun geometry do not provide feasible solutions. However, these tests show that a smaller transverse cathode diameter with a flat surface and a slightly larger anode diameter could alleviate the current loss due to beam interactions with the anode in the presence of magnetic fields. Based on these findings, an initial geometry resembling a parallel plate capacitor with a hole in the anode is proposed. The optimization procedure finds a cathode-anode distance of 5 mm, a focusing electrode angle of 5°, and an anode drift tube length of 17.1 mm. Also, the linac can be displaced with ±15 cm along the axis of the 0.5 T magnet without capture efficiency reduction below the experimental value in zero field. In this range of linac displacements, the electron beam generated by the new gun geometry is more effectively injected into the linac in the presence of an external magnetic field, resulting in approximately 20% increase of the target current compared to the original gun geometry behavior at zero field. The new gun geometry can generate and accelerate electron beams in external magnetic fields without current loss for fields higher than 0.11 T. The new electron-gun geometry is robust enough to function in the fringe fields of the other two magnets with a target current loss of no more than 16% with respect to the current obtained with no external magnetic fields. Conclusions: In this work, a specially designed electron gun was presented which can operate in the presence of axisymmetric strong magnetic fringe fields of MRI magnets. Computer simulations show that the electron gun can produce high quality beams which can be injected into a straight through linac such as Varian 600C and accelerated with more efficiency in the presence of the external magnetic fields. Also, the new configuration allows linac displacements along the magnet axis in a range equal to the diameter of the imaging spherical volume of the magnet under consideration. The new electron gun-linac system can function in the fringe field of a MRI magnet if the field strength at the cathode position is higher than 0.11 T. The capture efficiency of the linac depends on the magnetic field strength and the field gradient. The higher the gradient the better the capture efficiency. The capture efficiency does not degrade more than 16%.

  10. Difference between healthy children and ADHD based on wavelet spectral analysis of nuclear magnetic resonance images

    SciTech Connect (OSTI)

    González Gómez Dulce, I. E-mail: emoreno@fcfm.buap.mx E-mail: joserm84@gmail.com; Moreno Barbosa, E. E-mail: emoreno@fcfm.buap.mx E-mail: joserm84@gmail.com; Hernández, Mario Iván Martínez E-mail: emoreno@fcfm.buap.mx E-mail: joserm84@gmail.com; Méndez, José Ramos E-mail: emoreno@fcfm.buap.mx E-mail: joserm84@gmail.com; Silvia, Hidalgo Tobón; Pilar, Dies Suarez E-mail: neurodoc@prodigy.net.mx; Eduardo, Barragán Pérez E-mail: neurodoc@prodigy.net.mx; Benito, De Celis Alonso

    2014-11-07

    The main goal of this project was to create a computer algorithm based on wavelet analysis of region of homogeneity images obtained during resting state studies. Ideally it would automatically diagnose ADHD. Because the cerebellum is an area known to be affected by ADHD, this study specifically analysed this region. Male right handed volunteers (infants with ages between 7 and 11 years old) were studied and compared with age matched controls. Statistical differences between the values of the absolute integrated wavelet spectrum were found and showed significant differences (p<0.0015) between groups. This difference might help in the future to distinguish healthy from ADHD patients and therefore diagnose ADHD. Even if results were statistically significant, the small size of the sample limits the applicability of this methods as it is presented here, and further work with larger samples and using freely available datasets must be done.

  11. IMMEDIATE JOB OPENINGS MRI technical developments and applications

    E-Print Network [OSTI]

    Duong, Timothy Q.

    ) the applications of these innovative imaging technologies to study anatomy, metabolism, physiology (such as blood) MRI: 3T/90cm whole-body Siemens TIM Trio + AC88 high performance gradient insert, and 6) Access

  12. IMMEDIATE JOB OPENING MRI technical developments and applications

    E-Print Network [OSTI]

    Duong, Timothy Q.

    ) the applications of these innovative imaging technologies to study anatomy, metabolism, physiology (such as blood + AC88 high performance gradient insert 6) MRI: 3T/90cm whole-body Philips Achieva There are also

  13. MRI of the human brain at 130 microtesla

    E-Print Network [OSTI]

    Inglis, Ben

    We present in vivo images of the human brain acquired with an ultralow field MRI (ULFMRI) system operating at a magnetic field B[subscript 0] ? 130 ?T. The system features prepolarization of the proton spins at B[subscript ...

  14. High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

    SciTech Connect (OSTI)

    Wu, Pei-Hsin; Chung, Hsiao-Wen; Tsai, Ping-Huei; Wu, Ming-Long; Chuang, Tzu-Chao; Shih, Yi-Yu; Huang, Teng-Yi

    2013-12-15

    Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm{sup 3} achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm{sup 3} voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm{sup 3} to 0.43 × 0.43 × 2 mm{sup 3} has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain.

  15. Neuroimaging at 1.5 T and 3.0 T: Comparison of Oxygenation-Sensitive Magnetic Resonance Imaging

    E-Print Network [OSTI]

    Glover, Gary H.

    and becomes a larger fraction of the total noise at 3.0 T. Activation of the primary motor and visual cortex a magnetic field strength of 1.5 Tesla (T) seems to represent a good compromise. Functional MRI (f

  16. Magnetic Resonance Imaging (MRI)has failed to distinguish between smaller gut regions and larger haemal sinuses in sea urchins (Echinodermata: Echinoidea)

    E-Print Network [OSTI]

    Holland, Nicholas D; Ghiselin, Michael T

    2009-01-01

    Commentary The sea urchin siphon is a narrow-bore tube thatof the intestine. Although a siphon is present in most seasea urchins actu- ally have a siphon instead and that our

  17. Performance Analysis between Two Sparsity Constrained MRI Methods: Highly Constrained Backprojection(HYPR) and Compressed Sensing(CS) for Dynamic Imaging 

    E-Print Network [OSTI]

    Arzouni, Nibal

    2012-10-19

    of the unknown x-f spectrum of the dynamic images. tF is the temporal Fourier transform to make the signal sparse. R is the radon transform, and sF is the Fourier transform along the radial direction of the sinogram. M is the sampling operator along... backprojection like inverse radon transform. The quality of the composite image determines the quality of the reconstructed time frames. The different time frames are reconstructed by multiplying the composite image with the corresponding weighting...

  18. Clustered Components Analysis for Functional MRI

    E-Print Network [OSTI]

    A human experiment was also designed to stimulate different functional cortices. ..... The log-likelihood is then calculated for the whole set of voxels. ...... A. R. Kay, and D. W. Tank, “Brain magnetic resonance imaging with contrast dependent.

  19. Tumor Shrinkage Assessed by Volumetric MRI in Long-Term Follow-Up After Fractionated Stereotactic Radiotherapy of Nonfunctioning Pituitary Adenoma

    SciTech Connect (OSTI)

    Kopp, Christine, E-mail: Christine.Kopp@lrz.tu-muenchen.de [Klinik und Poliklinik fuer Strahlentherapie und Radiologische Onkologie, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich (Germany); Theodorou, Marilena; Poullos, Nektarios; Jacob, Vesna; Astner, Sabrina T.; Molls, Michael [Klinik und Poliklinik fuer Strahlentherapie und Radiologische Onkologie, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich (Germany); Grosu, Anca-Ligia [Klinik fuer Strahlenheilkunde, Universitaet Freiburg, Freiburg (Germany)

    2012-03-01

    Purpose: To evaluate tumor control and side effects associated with fractionated stereotactic radiotherapy (FSRT) in the management of residual or recurrent nonfunctioning pituitary adenomas (NFPAs). Methods and Materials: We assessed exact tumor volume shrinkage in 16 patients with NFPA after FSRT. All patients had previously undergone surgery. Gross tumor volume (GTV) was outlined on contrast-enhanced magnetic resonance imaging (MRI) before and median 63 months (range, 28-100 months) after FSRT. MRI was performed as an axial three-dimensional gradient echo T1-weighted sequence at 1.6-mm slice thickness without gap (3D MRI). Results: Mean tumor size of all 16 pituitary adenomas before treatment was 7.4 mL (3.3-18.9 mL). We found shrinkage of the treated pituitary adenoma in all patients. Within a median follow-up of 63 months (28-100 months) an absolute mean volume reduction of 3.8 mL (0.9-12.4 mL) was seen. The mean relative size reduction compared with the volume before radiotherapy was 51% (22%-95%). Shrinkage measured by 3D MRI was greater at longer time intervals after radiotherapy. A strong negative correlation between the initial tumor volume and the absolute volume reduction after FSRT was found. There was no correlation between tumor size reduction and patient age, sex, or number of previous surgeries. Conclusions: By using 3D MRI in all patients undergoing FSRT of an NFPA, tumor shrinkage is detected. Our data demonstrate that volumetric assessment based on 3D MRI adds additional information to routinely used radiological response measurements. After FSRT a mean relative size reduction of 51% can be expected within 5 years.

  20. Ultrasound-Stimulated Acoustic Emission in Thermal Image-Guided HIFU Therapy: A Phantom Study

    SciTech Connect (OSTI)

    Jiang, C. P.; Lin, W. T. [Biomedical Engineering Center, Industrial Technology Research Institute, Hsinchu, Taiwan (China); Chen, W. S. [Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan (China)

    2006-05-08

    Magnetic resonance image (MRI) is a promising monitoring tool for non-invasive real-time thermal guidance in high intensity focused ultrasound (HIFU) during thermal ablation surgery. However, this approach has two main drawbacks: 1) majority of components need to be redesigned to be MR compatible in order to avoid effecting MR images, and 2) the cost of operating MRI facilities is high. Alternately, ultrasound-stimulated acoustic emission (USAE) method has been applied for detecting thermal variations in tissues. An optical transparent phantom, made from polyacrylamide, containing thermal sensitive indicator protein (Bovine Serum Albumin), was prepared for observing the HIFU-induced denaturalization. A thermal-couple was set up for validation of temperature distribution. Experimental results show that thermal image can be captured clearly under stationary conditions.

  1. Nanoscale femtosecond imaging of transient hot solid density plasmas with elemental and charge state sensitivity using resonant coherent diffraction

    E-Print Network [OSTI]

    Kluge, Thomas; Chung, H -K; Gutt, C; Huang, L G; Zacharias, M; Schramm, U; Cowan, T E

    2015-01-01

    Here we propose to exploit the low energy bandwidth, small wavelength and penetration power of ultrashort pulses from XFELs for resonant Small Angle Scattering (SAXS) on plasma structures in laser excited plasmas. Small angle scattering allows to detect nanoscale density fluctuations in forward scattering direction. Typically, the SAXS signal from laser excited plasmas is expected to be dominated by the free electron distribution. We propose that the ionic scattering signal becomes visible when the X-ray energy is in resonance with an electron transition between two bound states (Resonant coherent X-ray diffraction, RCXD). In this case the scattering cross-section dramatically increases so that the signal of X-ray scattering from ions silhouettes against the free electron scattering background which allows to measure the opacity and derived quantities with high spatial and temporal resolution, being fundamentally limited only by the X-ray wavelength and timing. Deriving quantities such as ion spatial distribu...

  2. NMR, MRI, and spectroscopic MRI in inhomogeneous fields

    DOE Patents [OSTI]

    Demas, Vasiliki; Pines, Alexander; Martin, Rachel W; Franck, John; Reimer, Jeffrey A

    2013-12-24

    A method for locally creating effectively homogeneous or "clean" magnetic field gradients (of high uniformity) for imaging (with NMR, MRI, or spectroscopic MRI) both in in-situ and ex-situ systems with high degrees of inhomogeneous field strength. THe method of imaging comprises: a) providing a functional approximation of an inhomogeneous static magnetic field strength B.sub.0({right arrow over (r)}) at a spatial position {right arrow over (r)}; b) providing a temporal functional approximation of {right arrow over (G)}.sub.shim(t) with i basis functions and j variables for each basis function, resulting in v.sub.ij variables; c) providing a measured value .OMEGA., which is an temporally accumulated dephasing due to the inhomogeneities of B.sub.0({right arrow over(r)}); and d) minimizing a difference in the local dephasing angle .phi.({right arrow over (r)},t)=.gamma..intg..sub.0.sup.t{square root over (|{right arrow over (B)}.sub.1({right arrow over (r)},t')|.sup.2+({right arrow over (r)}{right arrow over (G)}.sub.shimG.sub.shim(t')+.parallel.{right arrow over (B)}.sub.0({right arrow over (r)}).parallel..DELTA..omega.({right arrow over (r)},t'/.gamma/).sup.2)}dt'-.OMEGA. by varying the v.sub.ij variables to form a set of minimized v.sub.ij variables. The method requires calibration of the static fields prior to minimization, but may thereafter be implemented without such calibration, may be used in open or closed systems, and potentially portable systems.

  3. Nuclear magnetic resonance contrast agents

    DOE Patents [OSTI]

    Smith, P.H.; Brainard, J.R.; Jarvinen, G.D.; Ryan, R.R.

    1997-12-30

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC{sub 16}H{sub 14}N{sub 6}. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques. 10 figs.

  4. Nuclear magnetic resonance contrast agents

    DOE Patents [OSTI]

    Smith, Paul H. (Los Alamos, NM); Brainard, James R. (Los Alamos, NM); Jarvinen, Gordon D. (Los Alamos, NM); Ryan, Robert R. (Los Alamos, NM)

    1997-01-01

    A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC.sub.16 H.sub.14 N.sub.6. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques.

  5. SU-E-J-239: IMRT Planning of Prostate Cancer for a MRI-Linac Based On MRI Only

    SciTech Connect (OSTI)

    Chen, X; Prior, P; Paulson, E; Lawton, C; Li, X

    2014-06-01

    Purpose: : To investigate dosimetric differences between MRI- and CT-based IMRT planning for prostate cancer, the impact of a magnetic field in a MRI-Linac, and to explore the feasibility of IMRT planning based on MRI alone. Methods: IMRT plans were generated based on CT and MRI images acquired on two representative prostate-cancer patients using clinical dose volume constraints. A research planning system (Monaco, Elekta), which employs a Monte Carlo dose engine and includes a perpendicular magnetic field of 1.5T from an MRI-Linac, was used. Bulk electron density assignments based on organ-specific values from ICRU 46 were used to convert MRI (T2) to pseudo CT. With the same beam configuration as in the original CT plan, 5 additional plans were generated based on CT or MRI, with or without optimization (i.e., just recalculation) and with or without the magnetic field. The plan quality in terms of commonly used dose volume (DV) parameters for all plans was compared. The statistical uncertainty on dose was < 1%. Results: For plans with the same contour set but without re-optimization, the DV parameters were different from those for the original CT plan, mostly less than 5% with a few exceptions. These differences were reduced to mostly less than 3% when the plans were re-optimized. For plans with contours from MRI, the differences in the DV parameters varied depending on the difference in the contours as compared to CT. For the optimized plans with contours from MR, the differences for PTV were less than 3%. Conclusion: The prostate IMRT plans based on MRI-only for a MR-Linac were practically similar as compared to the CT plan under the same beam and optimization configuration if the difference on the structure delineation is excluded, indicating the feasibility of using MRI-only for prostate IMRT.

  6. In Situ Root System Architecture Extraction from Magnetic Resonance

    E-Print Network [OSTI]

    Behnke, Sven

    using SmartRoot (Lobet et al., 2011). It is tested on the basis of a MRI image of a 25 days old lupin was inspired by methods for blood vessel detection in MRI images. It describes the root system). Both systems work well and allow for continuous water flow. Slight differences in the connectivity

  7. Amplification of Xenon NMR and MRI by remote detection

    SciTech Connect (OSTI)

    Moule, Adam J.; Spence, Megan M.; Han, Song-I.; Seeley, JulietteA.; Pierce, Kimberly L.; Saxena, Sunil; Pines, Alexander

    2003-03-31

    A novel technique is proposed in which a nuclear magneticresonance (NMR) spectrum or magnetic resonance image (MRI) is encoded andstored as spin polarization and is then moved to a different physicallocation to be detected. Remote detection allows the separateoptimization of the encoding and detection steps, permitting theindependent choice of experimental conditions, and excitation anddetection methodologies. In the first experimental demonstration of thistechnique, we show that NMR signal can be amplified by taking diluted129Xe from a porous sample placed inside a large encoding coil, andconcentrating it into a smaller detection coil. In general, the study ofNMR active molecules at low concentration that have low physical fillingfactor is facilitated by remote detection. In the second experiment, MRIinformation encoded in a very low field magnet (4-7mT) is transferred toa high field magnet (4.2 T) in order to be detected under optimizedconditions. Furthermore, remote detection allows the utilization ofultra-sensitive optical or superconducting detection techniques, whichbroadens the horizon of NMR experimentation.

  8. Near-electrode imager

    DOE Patents [OSTI]

    Rathke, Jerome W. (Lockport, IL); Klingler, Robert J. (Westmont, IL); Woelk, Klaus (Wachtberg, DE); Gerald, II, Rex E. (Brookfield, IL)

    2000-01-01

    An apparatus, near-electrode imager, for employing nuclear magnetic resonance imaging to provide in situ measurements of electrochemical properties of a sample as a function of distance from a working electrode. The near-electrode imager uses the radio frequency field gradient within a cylindrical toroid cavity resonator to provide high-resolution nuclear magnetic resonance spectral information on electrolyte materials.

  9. Injection-controlled laser resonator

    DOE Patents [OSTI]

    Chang, J.J.

    1995-07-18

    A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality. 5 figs.

  10. Multimodal MRI Neuroimaging with Motion Compensation Based on Particle Filtering

    E-Print Network [OSTI]

    Chen, Yu-Hui; Kim, Boklye; Meyer, Charles; Hero, Alfred

    2015-01-01

    Head movement during scanning impedes activation detection in fMRI studies. Head motion in fMRI acquired using slice-based Echo Planar Imaging (EPI) can be estimated and compensated by aligning the images onto a reference volume through image registration. However, registering EPI images volume to volume fails to consider head motion between slices, which may lead to severely biased head motion estimates. Slice-to-volume registration can be used to estimate motion parameters for each slice by more accurately representing the image acquisition sequence. However, accurate slice to volume mapping is dependent on the information content of the slices: middle slices are information rich, while edge slides are information poor and more prone to distortion. In this work, we propose a Gaussian particle filter based head motion tracking algorithm to reduce the image misregistration errors. The algorithm uses a dynamic state space model of head motion with an observation equation that models continuous slice acquisitio...

  11. Improved nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOE Patents [OSTI]

    Fukushima, E.; Roeder, S.B.W.; Assink, R.A.; Gibson, A.A.V.

    1984-01-01

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  12. Numerical procedure for analyzing impurity-induced resonant-state STM images observed in high-T-c superconductors 

    E-Print Network [OSTI]

    Wang, Q.; Hu, Chia-Ren.

    2004-01-01

    been offerred to ex- plain this disagreement.5,6 Namely, finite LDOS are pre- dicted at the Zn or Cu sites only, with no continuous LDOS between these lattice sites. This is of course not what has been observed, which is quasi... two STM images. One is a topographic image (an energy- integrated spatial image), which gives the top BiO layer, showing only the Bi atoms. They are observed to be dis- placed from their ideal orthorhombic lattice sites, forming a supermodulation...

  13. Method of performing MRI with an atomic magnetometer

    SciTech Connect (OSTI)

    Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich

    2013-08-27

    A method and apparatus are provided for performing an in-situ magnetic resonance imaging of an object. The method includes the steps of providing an atomic magnetometer, coupling a magnetic field generated by magnetically resonating samples of the object through a flux transformer to the atomic magnetometer and measuring a magnetic resonance of the atomic magnetometer.

  14. Method of performing MRI with an atomic magnetometer

    SciTech Connect (OSTI)

    Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A.; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich

    2012-11-06

    A method and apparatus are provided for performing an in-situ magnetic resonance imaging of an object. The method includes the steps of providing an atomic magnetometer, coupling a magnetic field generated by magnetically resonating samples of the object through a flux transformer to the atomic magnetometer and measuring a magnetic resonance of the atomic magnetometer.

  15. Design of multi-channel radio-frequency front-end for 200mhz parallel magnetic resonance imaging 

    E-Print Network [OSTI]

    Liu, Xiaoqun

    2009-05-15

    ) which also acts as a variable gain amplifier (VGA). The quadrature image rejection downconverter consists of a quadrature generator, a passive mixer with a transimpedance amplifier which converts the output current signal of the passive mixer...

  16. Visualization of fused fMRI and SPECT imagery M. Aguilar and A.L. Garrett

    E-Print Network [OSTI]

    Garrett, Aaron

    stages of image enhancement, image fusion, and 3D volume generation. A method for image enhancement and fusion based on biological principles of color vision was implemented to combine fMRI (PD, T1, and T2) and SPECT imagery. The fusion system produces a single color image, which enhances and combines

  17. COBIOT-591; NO OF PAGES 8 Please cite this article in press as: Xia Z, Rao J. Biosensing and imaging based on bioluminescence resonance energy transfer, Curr Opin Biotechnol (2009), doi:10.1016/j.copbio.2009.01.001

    E-Print Network [OSTI]

    Rao, Jianghong

    2009-01-01

    and imaging based on bioluminescence resonance energy transfer, Curr Opin Biotechnol (2009), doi:10.1016/j resonance energy transfer Zuyong Xia and Jianghong Rao Bioluminescence resonance energy transfer (BRET) operates with biochemical energy generated by bioluminescent proteins to excite fluorophores and offers

  18. A finite elements method to solve the Bloch–Torrey equation applied to diffusion magnetic resonance imaging

    SciTech Connect (OSTI)

    Nguyen, Dang Van; Li, Jing-Rebecca; Grebenkov, Denis; Le Bihan, Denis

    2014-04-15

    The complex transverse water proton magnetization subject to diffusion-encoding magnetic field gradient pulses in a heterogeneous medium can be modeled by the multiple compartment Bloch–Torrey partial differential equation (PDE). In addition, steady-state Laplace PDEs can be formulated to produce the homogenized diffusion tensor that describes the diffusion characteristics of the medium in the long time limit. In spatial domains that model biological tissues at the cellular level, these two types of PDEs have to be completed with permeability conditions on the cellular interfaces. To solve these PDEs, we implemented a finite elements method that allows jumps in the solution at the cell interfaces by using double nodes. Using a transformation of the Bloch–Torrey PDE we reduced oscillations in the searched-for solution and simplified the implementation of the boundary conditions. The spatial discretization was then coupled to the adaptive explicit Runge–Kutta–Chebyshev time-stepping method. Our proposed method is second order accurate in space and second order accurate in time. We implemented this method on the FEniCS C++ platform and show time and spatial convergence results. Finally, this method is applied to study some relevant questions in diffusion MRI.

  19. MRI/TRUS data fusion for brachytherapy

    E-Print Network [OSTI]

    Daanen, V; Giraud, J Y; Fourneret, P; Descotes, J L; Bolla, M; Collomb, D; Troccaz, Jocelyne

    2006-01-01

    BACKGROUND: Prostate brachytherapy consists in placing radioactive seeds for tumour destruction under transrectal ultrasound imaging (TRUS) control. It requires prostate delineation from the images for dose planning. Because ultrasound imaging is patient- and operator-dependent, we have proposed to fuse MRI data to TRUS data to make image processing more reliable. The technical accuracy of this approach has already been evaluated. METHODS: We present work in progress concerning the evaluation of the approach from the dosimetry viewpoint. The objective is to determine what impact this system may have on the treatment of the patient. Dose planning is performed from initial TRUS prostate contours and evaluated on contours modified by data fusion. RESULTS: For the eight patients included, we demonstrate that TRUS prostate volume is most often underestimated and that dose is overestimated in a correlated way. However, dose constraints are still verified for those eight patients. CONCLUSIONS: This confirms our init...

  20. Anisotropy Characterization of I-125 Seed with Attached Encapsulated Cobalt Chloride Complex Contrast Agent Markers for MRI-Based Prostate Brachytherapy

    SciTech Connect (OSTI)

    Frank, Steven J., E-mail: sjfrank@mdanderson.or [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Tailor, Ramesh C.; Kudchadker, Rajat J. [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Martirosyan, Karen S. [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX (United States); Stafford, R. Jason; Elliott, Andrew M. [Department of Imaging Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Swanson, David A. [Department of Urology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Sing, David; Choi, Jonathan [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Mourtada, Firas; Ibbott, Geoffrey S. [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

    2011-07-01

    We have developed a novel MRI marker for prostate brachytherapy. The purpose of this study was to evaluate the changes in anisotropy when cobalt chloride complex contrast agent encapsulated contrast agent markers (C4-ECAM) were placed adjacent to an iodine-125 (I-125) titanium seed, and to verify that the C4-ECAMs were visible on magnetic resonance imaging (MRI) after radiation exposure. Two C4-ECAMs were verified to be MRI visible in a phantom before radiation exposure. The C4-ECAMs were then attached to each end of a 12.7-U (10-mCi) I-125 titanium seed in a polymer tube. Anisotropy was measured and analyzed with the seed alone and with attached C4-ECAMs by suspending thermoluminescent dosimeters in a water phantom in 2 circles surrounding the radioactive source with radius of 1 or 2 cm. A T1-weighted MRI evaluation of C4-ECAMs was then performed after exposure to the amount of radiation typically delivered during 1 month of prostate brachytherapy. Measured values of the anisotropy function F(r, {theta}) for the I-125 seed with and without the C4-ECAMs were mutually statistically indistinguishable (standard error of the mean <4.2%) and agreed well with published TG-43 values for the bare seed. As expected, the anisotropy function {phi}{sub an}(r) for the 2 datasets (with and without C4-ECAMs) derived from the measured F(r, {theta}) did not exhibit statistically measurable difference. Both datasets showed agreement with the published TG-43 {phi}{sub an}(r) for the bare seed. The C4-ECAMs were well visualized by MRI after 1 month of radiation exposure. There were no changes in anisotropy when the C4-ECAMs were placed next to an I-125 radioactive seed, and the C4-ECAMs were visualized after radiation exposure.

  1. SU-C-17A-05: Quantification of Intra-Fraction Motion of Breast Tumors Using Cine-MRI

    SciTech Connect (OSTI)

    Heijst, T van; Philippens, M; Bongard, D van den; Asselen, B van; Lagendijk, J; Kleijnen, J; Hartogh, M den

    2014-06-01

    Purpose: Magnetic resonance imaging (MRI) enables direct characterization of intra-fraction motion ofbreast tumors, due to high softtissue contrast and geometric accuracy. The purpose is to analyzethis motion in early-stage breast-cancer patients using pre-operative supine cine-MRI. Methods: MRI was performed in 12 female early-stage breast-cancer patients on a 1.5-T Ingenia (Philips)wide-bore scanner in supine radiotherapy (RT) position, prior to breast-conserving surgery. Twotwodimensional (2D) T2-weighted balanced fast-field echo (cine-MRI) sequences were added tothe RT protocol, oriented through the tumor. They were alternately acquired in the transverse andsagittal planes, every 0.3 s during 1 min. A radiation oncologist delineated gross target volumes(GTVs) on 3D contrast-enhanced MRI. Clinical target volumes (CTV = GTV + 15 mm isotropic)were generated and transferred onto the fifth time-slice of the time-series, to which subsequents lices were registered using a non-rigid Bspline algorithm; delineations were transformed accordingly. To evaluate intra-fraction CTV motion, deformation fields between the transformed delineations were derived to acquire the distance ensuring 95% surface coverage during scanning(P95%), for all in-plane directions: anteriorposterior (AP), left-right (LR), and caudal-cranial(CC). Information on LR was derived from transverse scans, CC from sagittal scans, AP fromboth sets. Results: Time-series with registration errors - induced by motion artifacts - were excluded by visual inspection. For our analysis, 11 transverse, and 8 sagittal time-series were taken into account. Themedian P95% calculated in AP (19 series), CC (8), and LR (11) was 1.8 mm (range: 0.9–4.8), 1.7mm (0.8–3.6), and 1.0 mm (0.6–3.5), respectively. Conclusion: Intra-fraction motion analysis of breast tumors was achieved using cine-MRI. These first results show that in supine RT position, motion amplitudes are limited. This information can be used for adaptive RT planning, and to develop preoperative partial-breast RT strategies, such asablative RT for early-stage breast-cancer patients.

  2. Velocity and concentration studies of flowing suspensions by nuclear magnetic resonance imaging. Technical progress report, April--June 1996

    SciTech Connect (OSTI)

    1997-05-01

    Our search for a suitable combination of imageable particles in a carrier liquid which will not dissolve the particles has led us to try pharmaceutical particles in silicon oil. This combination doses not seem to last long enough for adequate NMR measurements. Results are discussed.

  3. Three-Dimensional Mapping of Ozone-Induced Injury in the Nasal Airways of Monkeys Using Magnetic Resonance Imaging and Morphometric Techniques

    SciTech Connect (OSTI)

    Carey, Stephen A.; Minard, Kevin R.; Trease, Lynn L.; Wagner, James G.; Garcia, Guilherme M.; Ballinger, Carol A.; Kimbell, Julia; Plopper, Charles G.; Corley, Rick A.; Postlewait, Ed; Harkema, Jack R.

    2007-03-01

    ABSTRACT Age-related changes in gross and microscopic structure of the nasal cavity can alter local tissue susceptibility as well as the dose of inhaled toxicant delivered to susceptible sites. This article describes a novel method for the use of magnetic resonance imaging, 3-dimensional airway modeling, and morphometric techniques to characterize the distribution and magnitude of ozone-induced nasal injury in infant monkeys. Using this method, we are able to generate age-specific, 3-dimensional, epithelial maps of the nasal airways of infant Rhesus macaques. The principal nasal lesions observed in this primate model of ozone-induced nasal toxicology were neutrophilic rhinitis, along with necrosis and exfoliation of the epithelium lining the anterior maxilloturbinate. These lesions, induced by acute or cyclic (episodic) exposures, were examined by light microscopy, quantified by morphometric techniques, and mapped on 3-dimensional models of the nasal airways. Here, we describe the histopathologic, imaging, and computational biology methods developed to efficiently characterize, localize, quantify, and map these nasal lesions. By combining these techniques, the location and severity of the nasal epithelial injury were correlated with epithelial type, nasal airway geometry, and local biochemical and molecular changes on an individual animal basis. These correlations are critical for accurate predictive modeling of exposure-dose-response relationships in the nasal airways, and subsequent extrapolation of nasal findings in animals to humans for developing risk assessment.

  4. SQUID-Detected MRI in the Limit of Zero Static Field

    E-Print Network [OSTI]

    Kelso, Nathan Dean

    2010-01-01

    image acquired in the zero-static-?eld limit . . . . . 6.3.2Protocol for MRI in zero static ?power dissipated in a static ?eld . . . . . . 7.4 Comparison

  5. O2-06-05 AVOXEL-BASED MORPHOMETRY STUDY OF VOLUMETRIC MRI IN FAMILIAL ALZHEIMER'S

    E-Print Network [OSTI]

    Thompson, Paul

    O2-06-05 AVOXEL-BASED MORPHOMETRY STUDY OF VOLUMETRIC MRI IN FAMILIAL ALZHEIMER'S DISEASE David the different groups. Tissue segmentation and spatial normalization of volumetric T1-weighted images were

  6. Preliminary Study of Oxygen-Enhanced Longitudinal Relaxation in MRI: A Potential Novel Biomarker of Oxygenation Changes in Solid Tumors

    SciTech Connect (OSTI)

    O'Connor, James P.B.; Naish, Josephine H.; Parker, Geoff J.M.; Waterton, John C.; Watson, Yvonne; Jayson, Gordon C.; Buonaccorsi, Giovanni A.; Cheung, Sue; Buckley, David L.; McGrath, Deirdre M.; West, Catharine M.L.; Davidson, Susan E.; Roberts, Caleb; Mills, Samantha J.; Mitchell, Claire L.; Hope, Lynn; Ton, N. Chan; Jackson, Alan

    2009-11-15

    Purpose: There is considerable interest in developing non-invasive methods of mapping tumor hypoxia. Changes in tissue oxygen concentration produce proportional changes in the magnetic resonance imaging (MRI) longitudinal relaxation rate (R{sub 1}). This technique has been used previously to evaluate oxygen delivery to healthy tissues and is distinct from blood oxygenation level-dependent (BOLD) imaging. Here we report application of this method to detect alteration in tumor oxygenation status. Methods and materials: Ten patients with advanced cancer of the abdomen and pelvis underwent serial measurement of tumor R{sub 1} while breathing medical air (21% oxygen) followed by 100% oxygen (oxygen-enhanced MRI). Gadolinium-based dynamic contrast-enhanced MRI was then performed to compare the spatial distribution of perfusion with that of oxygen-induced DELTAR{sub 1}. Results: DELTAR{sub 1} showed significant increases of 0.021 to 0.058 s{sup -1} in eight patients with either locally recurrent tumor from cervical and hepatocellular carcinomas or metastases from ovarian and colorectal carcinomas. In general, there was congruency between perfusion and oxygen concentration. However, regional mismatch was observed in some tumor cores. Here, moderate gadolinium uptake (consistent with moderate perfusion) was associated with low area under the DELTAR{sub 1} curve (consistent with minimal increase in oxygen concentration). Conclusions: These results provide evidence that oxygen-enhanced longitudinal relaxation can monitor changes in tumor oxygen concentration. The technique shows promise in identifying hypoxic regions within tumors and may enable spatial mapping of change in tumor oxygen concentration.

  7. Magnetic Resonance Imaging-Based Target Volume Delineation in Radiation Therapy Treatment Planning for Brain Tumors Using Localized Region-Based Active Contour

    SciTech Connect (OSTI)

    Aslian, Hossein; Sadeghi, Mahdi; Mahdavi, Seied Rabie; Babapour Mofrad, Farshid; Astarakee, Mahdi; Khaledi, Navid; Fadavi, Pedram

    2013-09-01

    Purpose: To evaluate the clinical application of a robust semiautomatic image segmentation method to determine the brain target volumes in radiation therapy treatment planning. Methods and Materials: A local robust region-based algorithm was used on MRI brain images to study the clinical target volume (CTV) of several patients. First, 3 oncologists delineated CTVs of 10 patients manually, and the process time for each patient was calculated. The averages of the oncologists’ contours were evaluated and considered as reference contours. Then, to determine the CTV through the semiautomatic method, a fourth oncologist who was blind to all manual contours selected 4-8 points around the edema and defined the initial contour. The time to obtain the final contour was calculated again for each patient. Manual and semiautomatic segmentation were compared using 3 different metric criteria: Dice coefficient, Hausdorff distance, and mean absolute distance. A comparison also was performed between volumes obtained from semiautomatic and manual methods. Results: Manual delineation processing time of tumors for each patient was dependent on its size and complexity and had a mean (±SD) of 12.33 ± 2.47 minutes, whereas it was 3.254 ± 1.7507 minutes for the semiautomatic method. Means of Dice coefficient, Hausdorff distance, and mean absolute distance between manual contours were 0.84 ± 0.02, 2.05 ± 0.66 cm, and 0.78 ± 0.15 cm, and they were 0.82 ± 0.03, 1.91 ± 0.65 cm, and 0.7 ± 0.22 cm between manual and semiautomatic contours, respectively. Moreover, the mean volume ratio (=semiautomatic/manual) calculated for all samples was 0.87. Conclusions: Given the deformability of this method, the results showed reasonable accuracy and similarity to the results of manual contouring by the oncologists. This study shows that the localized region-based algorithms can have great ability in determining the CTV and can be appropriate alternatives for manual approaches in brain cancer.

  8. SU-E-J-193: Feasibility of MRI-Only Based IMRT Planning for Pancreatic Cancer

    SciTech Connect (OSTI)

    Prior, P; Botros, M; Chen, X; Paulson, E; Erickson, B; Li, X

    2014-06-01

    Purpose: With the increasing use of MRI simulation and the advent of MRI-guided delivery, it is desirable to use MRI only for treatment planning. In this study, we assess the dosimetric difference between MRI- and CTbased IMRT planning for pancreatic cancer. Methods: Planning CTs and MRIs acquired for a representative pancreatic cancer patient were used. MRI-based planning utilized forced relative electron density (rED) assignment of organ specific values from IRCU report 46, where rED = 1.029 for PTV and a rED = 1.036 for non-specified tissue (NST). Six IMRT plans were generated with clinical dose-volume (DV) constraints using a research Monaco planning system employing Monte Carlo dose calculation with optional perpendicular magnetic field (MF) of 1.5T. The following five plans were generated and compared with the planning CT: 1.) CT plan with MF and dose recalculation without optimization; 2.) MRI (T2) plan with target and OARs redrawn based on MRI, forced rED, no MF, and recalculation without optimization; 3.) Similar as in 2 but with MF; 4.) MRI plan with MF but without optimization; and 5.) Similar as in 4 but with optimization. Results: Generally, noticeable differences in PTV point doses and DV parameters (DVPs) between the CT-and MRI-based plans with and without the MF were observed. These differences between the optimized plans were generally small, mostly within 2%. Larger differences were observed in point doses and mean doses for certain OARs between the CT and MRI plan, mostly due to differences between image acquisition times. Conclusion: MRI only based IMRT planning for pancreatic cancer is feasible. The differences observed between the optimized CT and MRI plans with or without the MF were practically negligible if excluding the differences between MRI and CT defined structures.

  9. Preoperative 3-Tesla Multiparametric Endorectal Magnetic Resonance Imaging Findings and the Odds of Upgrading and Upstaging at Radical Prostatectomy in Men With Clinically Localized Prostate Cancer

    SciTech Connect (OSTI)

    Hegde, John V. [Harvard Medical School, Boston, Massachusetts (United States) [Harvard Medical School, Boston, Massachusetts (United States); Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States); Chen, Ming-Hui [Department of Statistics, University of Connecticut, Storrs, Connecticut (United States)] [Department of Statistics, University of Connecticut, Storrs, Connecticut (United States); Mulkern, Robert V. [Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States) [Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States); Department of Radiology, Children's Hospital Boston, Boston, Massachusetts (United States); Fennessy, Fiona M. [Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States) [Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States); Department of Imaging, Dana-Farber Cancer Institute, Boston, Massachusetts (United States); D'Amico, Anthony V. [Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Boston, Massachusetts (United States)] [Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Tempany, Clare M.C., E-mail: ctempany@bwh.harvard.edu [Division of MRI, Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts (United States)

    2013-02-01

    Purpose: To investigate whether 3-T esla (3T) multiparametric endorectal MRI (erMRI) can add information to established predictors regarding occult extraprostatic or high-grade prostate cancer (PC) in men with clinically localized PC. Methods and Materials: At a single academic medical center, this retrospective study's cohort included 118 men with clinically localized PC who underwent 3T multiparametric erMRI followed by radical prostatectomy, from 2008 to 2011. Multivariable logistic regression analyses in all men and in 100 with favorable-risk PC addressed whether erMRI evidence of T3 disease was associated with prostatectomy T3 or Gleason score (GS) 8-10 (in patients with biopsy GS {<=}7) PC, adjusting for age, prostate-specific antigen level, clinical T category, biopsy GS, and percent positive biopsies. Results: The accuracy of erMRI prediction of extracapsular extension and seminal vesicle invasion was 75% and 95%, respectively. For all men, erMRI evidence of a T3 lesion versus T2 was associated with an increased odds of having pT3 disease (adjusted odds ratio [AOR] 4.81, 95% confidence interval [CI] 1.36-16.98, P=.015) and pGS 8-10 (AOR 5.56, 95% CI 1.10-28.18, P=.038). In the favorable-risk population, these results were AOR 4.14 (95% CI 1.03-16.56), P=.045 and AOR 7.71 (95% CI 1.36-43.62), P=.021, respectively. Conclusions: Three-Tesla multiparametric erMRI in men with favorable-risk PC provides information beyond that contained in known preoperative predictors about the presence of occult extraprostatic and/or high-grade PC. If validated in additional studies, this information can be used to counsel men planning to undergo radical prostatectomy or radiation therapy about the possible need for adjuvant radiation therapy or the utility of adding hormone therapy, respectively.

  10. Temperature elevation by HIFU in ex vivo porcine muscle: MRI measurement and simulation study

    SciTech Connect (OSTI)

    Solovchuk, Maxim A., E-mail: solovchuk@gmail.com [Center for Advanced Study in Theoretical Sciences (CASTS), National Taiwan University, Taipei 10617, Taiwan (China); Hwang, San Chao; Chang, Hsu [Medical Engineering Research Division, National Health Research Institute, Miaoli 35053, Taiwan (China)] [Medical Engineering Research Division, National Health Research Institute, Miaoli 35053, Taiwan (China); Thiriet, Marc [Sorbonne Universités, UPMC Univ Paris 06, UMR 7598, Laboratoire Jacques-Louis Lions, F-75005, Paris (France)] [Sorbonne Universités, UPMC Univ Paris 06, UMR 7598, Laboratoire Jacques-Louis Lions, F-75005, Paris (France); Sheu, Tony W. H., E-mail: twhsheu@ntu.edu.tw [Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan, Republic of China and Center for Advanced Study in Theoretical Sciences (CASTS), National Taiwan University, Taipei 10617, Taiwan (China)] [Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan, Republic of China and Center for Advanced Study in Theoretical Sciences (CASTS), National Taiwan University, Taipei 10617, Taiwan (China)

    2014-05-15

    Purpose: High-intensity focused ultrasound is a rapidly developing medical technology with a large number of potential clinical applications. Computational model can play a pivotal role in the planning and optimization of the treatment based on the patient's image. Nonlinear propagation effects can significantly affect the temperature elevation and should be taken into account. In order to investigate the importance of nonlinear propagation effects, nonlinear Westervelt equation was solved. Weak nonlinear propagation effects were studied. The purpose of this study was to investigate the correlation between the predicted and measured temperature elevations and lesion in a porcine muscle. Methods: The investigated single-element transducer has a focal length of 12 cm, an aperture of 8 cm, and frequency of 1.08 MHz. Porcine muscle was heated for 30 s by focused ultrasound transducer with an acoustic power in the range of 24–56 W. The theoretical model consists of nonlinear Westervelt equation with relaxation effects being taken into account and Pennes bioheat equation. Results: Excellent agreement between the measured and simulated temperature rises was found. For peak temperatures above 85–90?°C “preboiling” or cavitation activity appears and lesion distortion starts, causing small discrepancy between the measured and simulated temperature rises. From the measurements and simulations, it was shown that distortion of the lesion was caused by the “preboiling” activity. Conclusions: The present study demonstrated that for peak temperatures below 85–90?°C numerical simulation results are in excellent agreement with the experimental data in three dimensions. Both temperature rise and lesion size can be well predicted. Due to nonlinear effect the temperature in the focal region can be increased compared with the linear case. The current magnetic resonance imaging (MRI) resolution is not sufficient. Due to the inevitable averaging the measured temperature can be 10–30?°C lower than the peak temperature. Computational fluid dynamics can provide additional important information that is lost using a state of the art MRI device.

  11. MRI of prostate brachytherapy seeds at high field: A study in phantom

    SciTech Connect (OSTI)

    Thomas, S. D.; Wachowicz, K.; Fallone, B. G. [Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Division of Medical Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Physics and Department of Oncology, Division of Medical Physics, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2009-11-15

    Postimplant evaluation of prostate brachytherapy using magnetic resonance imaging (MRI) at 1.5 T has met with some difficulties due to the uncertainty associated with seed localization despite the excellent anatomical delineation this imaging modality can achieve. Seeds in vascularized regions or outside the prostate, where signal heterogeneity or drop off can obscure their position, can be difficult to identify. The increase in SNR available at 3.0 T offers the potential to improve these issues with visualization. However, before moving directly to in vivo studies, it is important to investigate the effects of artifact size on the ability to localize multiple seeds in close proximity. These artifacts are of extra concern at higher field because of the increased induced field distortions surrounding the seeds. A single prostate brachytherapy seed (IMC6711, OncoSeed) and arrays of seed pairs were suspended in a porcine gel medium and imaged on 1.5 and 3 T MRI scanners for comparison. Two basic acquisition techniques utilized in a wide array of clinical sequences [spin-echo based and gradient-echo (GE) based] were investigated for the types of artifacts they produce, and their dependence on field. Analysis of the resulting voids was performed to determine the relative size of seeds as seen on the images, as well as the ability to distinguish seeds at close proximity. The seed voids at 3 T were only slightly larger than those obtained at 1.5 T (0.5 mm longer and wider) when using a spin-echo type sequence. For this work, the authors used a proton density fast spin-echo (FSE) sequence. These results are promising for the use of 3 T imaging for postimplant evaluation since the SNR will increase by roughly a factor of 2 with only a limited corresponding increase in artifact size. The minimum separation of the seeds to be completely distinguished using void analysis increased from between 1.5 and 3 mm to between 3 and 4.5 mm when going from 1.5 to 3 T FSE imaging. The minimum separation of the seeds for GE at the demonstration TE of 11 ms was found to be between 3 and 4.5 mm for 1.5 T and between 4.5 and 6 mm for 3 T. These GE artifact dimensions will scale down with TE and, as this happens, approach the dimensions of the FSE artifacts given above.

  12. Preliminary sex differences in human cortical BOLD fMRI activity during the preparation of increasingly complex

    E-Print Network [OSTI]

    Sergio, Lauren E.

    Preliminary sex differences in human cortical BOLD fMRI activity during the preparation imaging (fMRI) to show significant sex-related differences in human brain activity during visual-to-motor transformation tasks. Although the behavioural performance of the male and female groups did not differ, sex

  13. SU-E-I-53: Variation in Measurements of Breast Skin Thickness Obtained Using Different Imaging Modalities

    SciTech Connect (OSTI)

    Nguyen, U; Kumaraswamy, N; Markey, M

    2014-06-01

    Purpose: To investigate variation in measurements of breast skin thickness obtained using different imaging modalities, including mammography, computed tomography (CT), ultrasound, and magnetic resonance imaging (MRI). Methods: Breast skin thicknesses as measured by mammography, CT, ultrasound, and MRI were compared. Mammographic measurements of skin thickness were obtained from published studies that utilized standard positioning (upright) and compression. CT measurements of skin thickness were obtained from a published study of a prototype breast CT scanner in which the women were in the prone position and the breast was uncompressed. Dermatological ultrasound exams of the breast skin were conducted at our institution, with the subjects in the upright position and the breast uncompressed. Breast skin thickness was calculated from breast MRI exams at our institution, with the patient in the prone position and the breast uncompressed. Results: T tests for independent samples demonstrated significant differences in the mean breast skin thickness as measured by different imaging modalities. Repeated measures ANOVA revealed significant differences in breast skin thickness across different quadrants of the breast for some modalities. Conclusion: The measurement of breast skin thickness is significantly different across different imaging modalities. Differences in the amount of compression and differences in patient positioning are possible reasons why measurements of breast skin thickness vary by modality.

  14. Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system

    SciTech Connect (OSTI)

    Lillaney, Prasheel; Pelc, Norbert [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States); Shin Mihye [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Hinshaw, Waldo; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Bennett, N. Robert [Department of Radiology, Stanford University, Stanford, California 94305 and Qualcomm MEMS Technologies, San Jose, California 95134 (United States)

    2013-02-15

    Purpose: Using hybrid x-ray/MR (XMR) systems for image guidance during interventional procedures could enhance the diagnosis and treatment of neurologic, oncologic, cardiovascular, and other disorders. The authors propose a close proximity hybrid system design in which a C-arm fluoroscopy unit is placed immediately adjacent to the solenoid magnet of a MR system with a minimum distance of 1.2 m between the x-ray and MR imaging fields of view. Existing rotating anode x-ray tube designs fail within MR fringe field environments because the magnetic fields alter the electron trajectories in the x-ray tube and act as a brake on the induction motor, reducing the rotation speed of the anode. In this study the authors propose a novel motor design that avoids the anode rotation speed reduction. Methods: The proposed design replaces the permanent magnet stator found in brushed dc motors with the radial component of the MR fringe field. The x-ray tube is oriented such that the radial component of the MR fringe field is orthogonal to the cathode-anode axis. Using a feedback position sensor and the support bearings as electrical slip rings, the authors use electrical commutation to eliminate the need for mechanical brushes and commutators. A vacuum compatible prototype of the proposed motor design was assembled, and its performance was evaluated at various operating conditions. The prototype consisted of a 3.1 in. diameter anode rated at 300 kHU with a ceramic rotor that was 5.6 in. in length and had a 2.9 in. diameter. The material chosen for all ceramic components was MACOR, a machineable glass ceramic developed by Corning Inc. The approximate weight of the entire assembly was 1750 g. The maximum rotation speed, angular acceleration, and acceleration time of the motor design were investigated, as well as the dependence of these parameters on rotor angular offset, magnetic field strength, and field orientation. The resonance properties of the authors' assembly were also evaluated to determine its stability during acceleration, and a pulse width modulation algorithm was implemented to control the rotation speed of the motor. Results: At a magnetic flux density of 41 mT orthogonal to the axis of rotation (on the lower end of the expected flux density in the MR suite) the maximum speed of the motor was found to be 5150 revolutions per minute (rpm). The acceleration time necessary to reach 3000 rpm was found to be approximately 10 s at 59 mT. The resonance frequency of the assembly with the anode attached was 1310 rpm (21.8 Hz) which is far below the desired operating speeds. Pulse width modulation provides an effective method to control the speed of the motor with a resolution of 100 rpm. Conclusions: The proposed design can serve as a direct replacement to the conventional induction motor used in rotating anode x-ray tubes. It does not suffer from a reduced rotation speed when operating in a MR environment. The presence of chromic steel bearings in the prototype prevented testing at the higher field strengths, and future iterations of the design could eliminate this shortcoming. The prototype assembly demonstrates proof of concept of the authors' design and overcomes one of the major obstacles for a MR compatible rotating anode x-ray tube.

  15. WE-G-17A-09: Novel Magnetic Shielding Design for Inline and Perpendicular Integrated 6 MV Linac and 1.0 T MRI Systems

    SciTech Connect (OSTI)

    Li, X; Ma, B; Kuang, Y; Diao, X

    2014-06-15

    Purpose: The influence of fringe magnetic fields delivered by magnetic resonance imaging (MRI) on the beam generation and transportation in Linac is still a major challenge for the integration of linear accelerator and MRI (Linac-MRI). In this study, we investigated an optimal magnetic shielding design for Linac-MRI and further characterized the beam trajectory in electron gun. Methods: Both inline and perpendicular configurations were analyzed in this study. The configurations, comprising a Linac-MRI with a 100cm SAD and an open 1.0 T superconductive magnet, were simulated by the 3D finite element method (FEM). The steel shielding around the Linac was included in the 3D model, the thickness of which was varied from 1mm to 20mm, and magnetic field maps were acquired with and without additional shielding. The treatment beam trajectory in electron gun was evaluated using OPERA 3d SCALA with and without shielding cases. Results: When Linac was not shielded, the uniformity of diameter sphere volume (DSV) (30cm) was about 5 parts per million (ppm) and the fringe magnetic fields in electron gun were more than 0.3 T. With shielding, the magnetic fields in electron gun were reduced to less than 0.01 T. For the inline configuration, the radial magnetic fields in the Linac were about 0.02T. A cylinder steel shield used (5mm thick) altered the uniformity of DSV to 1000 ppm. For the perpendicular configuration, the Linac transverse magnetic fields were more than 0.3T, which altered the beam trajectory significantly. A 8mm-thick cylinder steel shield surrounding the Linac was used to compensate the output losses of Linac, which shifted the magnetic fields' uniformity of DSV to 400 ppm. Conclusion: For both configurations, the Linac shielding was used to ensure normal operation of the Linac. The effect of magnetic fields on the uniformity of DSV could be modulated by the shimming technique of the MRI magnet. NIH/NIGMS grant U54 GM104944, Lincy Endowed Assistant Professorship.

  16. Impact of the MLC on the MRI field distortion of a prototype MRI-linac

    SciTech Connect (OSTI)

    Kolling, Stefan; Keall, Paul; Oborn, Brad

    2013-12-15

    Purpose: To cope with intrafraction tumor motion, integrated MRI-linac systems for real-time image guidance are currently under development. The multileaf collimator (MLC) is a key component in every state-of-the-art radiotherapy treatment system, allowing for accurate field shaping and tumor tracking. This work quantifies the magnetic impact of a widely used MLC on the MRI field homogeneity for such a modality.Methods: The finite element method was employed to model a MRI-linac assembly comprised of a 1.0?T split-bore MRI magnet and the key ferromagnetic components of a Varian Millennium 120 MLC, namely, the leaves and motors. Full 3D magnetic field maps of the system were generated. From these field maps, the peak-to-peak distortion within the MRI imaging volume was evaluated over a 30?cm diameter sphere volume (DSV) around the isocenter and compared to a maximum preshim inhomogeneity of 300??T. Five parametric studies were performed: (1) The source-to-isocenter distance (SID) was varied from 100 to 200?cm, to span the range of a compact system to that with lower magnetic coupling. (2) The MLC model was changed from leaves only to leaves with motors, to determine the contribution to the total distortion caused by MLC leaves and motors separately. (3) The system was configured in the inline or perpendicular orientation, i.e., the linac treatment beam was oriented parallel or perpendicular to the magnetic field direction. (4) The treatment field size was varied from 0 × 0 to 20×20?cm{sup 2}, to span the range of clinical treatment fields. (5) The coil currents were scaled linearly to produce magnetic field strengths B{sub 0} of 0.5, 1.0, and 1.5?T, to estimate how the MLC impact changes with B{sub 0}.Results: (1) The MLC-induced MRI field distortion fell continuously with increasing SID. (2) MLC leaves and motors were found to contribute to the distortion in approximately equal measure. (3) Due to faster falloff of the fringe field, the field distortion was generally smaller in the perpendicular beam orientation. The peak-to-peak DSV distortion was below 300??T at SID?130?cm (perpendicular) and SID?140?cm (inline) for the 1.0?T design. (4) The simulation of different treatment fields was identified to cause dynamic changes in the field distribution. However, the estimated residual distortion was below 1.2?mm geometric distortion at SID?120?cm (perpendicular) and SID?130?cm (inline) for a 10?mT/m frequency-encoding gradient. (5) Due to magnetic saturation of the MLC materials, the field distortion remained constant at B{sub 0}>1.0?T.Conclusions: This work shows that the MRI field distortions caused by the MLC cannot be ignored and must be thoroughly investigated for any MRI-linac system. The numeric distortion values obtained for our 1.0?T magnet may vary for other magnet designs with substantially different fringe fields, however the concept of modest increases in the SID to reduce the distortion to a shimmable level is generally applicable.

  17. ORIGINAL ARTICLES An fMRI Study of Anterior Cingulate Function in

    E-Print Network [OSTI]

    Whalen, Paul J.

    integrity of anterior cingulate cortex in PTSD. Methods: Eight Vietnam combat veterans with PTSD (PTSD Group) and eight Vietnam combat veterans without PTSD (non-PTSD Group) underwent functional magnetic resonance General Negative compar- ison, the non-PTSD group exhibited significant fMRI blood oxygenation level

  18. Magnetic resonance imaging and computational fluid dynamics (CFD) simulations of rabbit nasal airflows for the development of hybrid CFD/PBPK models

    SciTech Connect (OSTI)

    Corley, Richard A.; Minard, Kevin R.; Kabilan, Senthil; Einstein, Daniel R.; Kuprat, Andrew P.; harkema, J. R.; Kimbell, Julia; Gargas, M. L.; Kinzell, John H.

    2009-06-01

    The percentages of total air?ows over the nasal respiratory and olfactory epithelium of female rabbits were cal-culated from computational ?uid dynamics (CFD) simulations of steady-state inhalation. These air?ow calcula-tions, along with nasal airway geometry determinations, are critical parameters for hybrid CFD/physiologically based pharmacokinetic models that describe the nasal dosimetry of water-soluble or reactive gases and vapors in rabbits. CFD simulations were based upon three-dimensional computational meshes derived from magnetic resonance images of three adult female New Zealand White (NZW) rabbits. In the anterior portion of the nose, the maxillary turbinates of rabbits are considerably more complex than comparable regions in rats, mice, mon-keys, or humans. This leads to a greater surface area to volume ratio in this region and thus the potential for increased extraction of water soluble or reactive gases and vapors in the anterior portion of the nose compared to many other species. Although there was considerable interanimal variability in the ?ne structures of the nasal turbinates and air?ows in the anterior portions of the nose, there was remarkable consistency between rabbits in the percentage of total inspired air?ows that reached the ethmoid turbinate region (~50%) that is presumably lined with olfactory epithelium. These latter results (air?ows reaching the ethmoid turbinate region) were higher than previous published estimates for the male F344 rat (19%) and human (7%). These di?erences in regional air?ows can have signi?cant implications in interspecies extrapolations of nasal dosimetry.

  19. MRI/TRUS data fusion for prostate brachytherapy. Preliminary results

    E-Print Network [OSTI]

    Reynier, Christophe; Fourneret, Philippe; Dusserre, André; Gay-Jeune, Cécile; Descotes, Jean-Luc; Bolla, Michel; Giraud, Jean-Yves

    2008-01-01

    Prostate brachytherapy involves implanting radioactive seeds (I125 for instance) permanently in the gland for the treatment of localized prostate cancers, e.g., cT1c-T2a N0 M0 with good prognostic factors. Treatment planning and seed implanting are most often based on the intensive use of transrectal ultrasound (TRUS) imaging. This is not easy because prostate visualization is difficult in this imaging modality particularly as regards the apex of the gland and from an intra- and interobserver variability standpoint. Radioactive seeds are implanted inside open interventional MR machines in some centers. Since MRI was shown to be sensitive and specific for prostate imaging whilst open MR is prohibitive for most centers and makes surgical procedures very complex, this work suggests bringing the MR virtually in the operating room with MRI/TRUS data fusion. This involves providing the physician with bi-modality images (TRUS plus MRI) intended to improve treatment planning from the data registration stage. The pape...

  20. 3D and 4D magnetic susceptibility tomography based on complex MR images

    DOE Patents [OSTI]

    Chen, Zikuan; Calhoun, Vince D

    2014-11-11

    Magnetic susceptibility is the physical property for T2*-weighted magnetic resonance imaging (T2*MRI). The invention relates to methods for reconstructing an internal distribution (3D map) of magnetic susceptibility values, .chi. (x,y,z), of an object, from 3D T2*MRI phase images, by using Computed Inverse Magnetic Resonance Imaging (CIMRI) tomography. The CIMRI technique solves the inverse problem of the 3D convolution by executing a 3D Total Variation (TV) regularized iterative convolution scheme, using a split Bregman iteration algorithm. The reconstruction of .chi. (x,y,z) can be designed for low-pass, band-pass, and high-pass features by using a convolution kernel that is modified from the standard dipole kernel. Multiple reconstructions can be implemented in parallel, and averaging the reconstructions can suppress noise. 4D dynamic magnetic susceptibility tomography can be implemented by reconstructing a 3D susceptibility volume from a 3D phase volume by performing 3D CIMRI magnetic susceptibility tomography at each snapshot time.

  1. Fast Algorithms for Image Reconstruction with Application to Partially Parallel MR Imaging

    E-Print Network [OSTI]

    Yin, Wotao

    Fast Algorithms for Image Reconstruction with Application to Partially Parallel MR Imaging Yunmei. Key words. Image reconstruction, Variable splitting, TV denoising, Nonlinear optimization 1 from an emerging magnetic resonance (MR) medical imaging technique known as partially parallel imaging

  2. Imaging

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you notHeat Pumps Heat Pumpsfacility doe logo CH2M-WG logoImaging

  3. Imaging

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation CurrentHenry Bellamy, Ph.D.FoodHydropower,PrincipalIdahoImaging Print The

  4. Imaging

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation CurrentHenry Bellamy, Ph.D.FoodHydropower,PrincipalIdahoImaging Print

  5. Magnetic Resonance Imaging of concrete

    E-Print Network [OSTI]

    Burgoyne, Chris

    it for babies, why not for concrete? #12;2 Non-destructive-testing Methods for Concrete Structures. Irie et al structure · In both cases procedure is destructive Systems to monitor concrete modulus · Ultra-sonic pulse and examined under microscope Limited number of sections can be obtained and only after unloading Destructive

  6. University of Vermont Center for Biomedical Imaging

    SciTech Connect (OSTI)

    Bernstein, Dr. Ira [University of Vermont and State Agricultural College

    2013-08-02

    This grant was awarded in support of Phase 2 of the University of Vermont Center for Biomedical Imaging. Phase 2 outlined several specific aims including: The development of expertise in MRI and fMRI imaging and their applications The acquisition of peer reviewed extramural funding in support of the Center The development of a Core Imaging Advisory Board, fee structure and protocol review and approval process.

  7. Effect of B1+ field correction on Quantitative Dynamic contrast enhanced MRI of the breast at 3.0T

    E-Print Network [OSTI]

    Bedair, Reem; Gilbert, Fiona

    2015-07-23

    15];94(3):427–35. Available from: http://www.nature.com/doifinder/10.1038/sj.bjc.6602948 15. Rahbar H, Partridge SC, DeMartini WB, Thursten B, Lehman CD. Clinical and technical considerations for high quality breast MRI at 3 Tesla. J Magn Reson... ;244(3). 17. El Khouli RH, Thomasson D, Pang Y, Bluemke DA. Effect of B1 Inhomogeneity- Correction on T1 -uniformity in breast MRI at 1.5 Tesla?: Preliminary results. Proc Intl Soc Mag Reson Med. 2009;17. 18. Hancu I, Lee S-K, Dixon WT, Sacolick L...

  8. Imaging Biomarker Dynamics in an Intracranial Murine Glioma Study of Radiation and Antiangiogenic Therapy

    SciTech Connect (OSTI)

    Chung, Caroline; Jalali, Shahrzad; Foltz, Warren; Burrell, Kelly; Wildgoose, Petra; Lindsay, Patricia; Graves, Christian; Camphausen, Kevin; Milosevic, Michael; Jaffray, David; Zadeh, Gelareh; Ménard, Cynthia

    2013-03-01

    Purpose: There is a growing need for noninvasive biomarkers to guide individualized spatiotemporal delivery of radiation therapy (RT) and antiangiogenic (AA) therapy for brain tumors. This study explored early biomarkers of response to RT and the AA agent sunitinib (SU), in a murine intracranial glioma model, using serial magnetic resonance imaging (MRI). Methods and Materials: Mice with MRI-visible tumors were stratified by tumor size into 4 therapy arms: control, RT, SU, and SU plus RT (SURT). Single-fraction conformal RT was delivered using MRI and on-line cone beam computed tomography (CT) guidance. Serial MR images (T2-weighted, diffusion, dynamic contrast-enhanced and gadolinium-enhanced T1-weighted scans) were acquired biweekly to evaluate tumor volume, apparent diffusion coefficient (ADC), and tumor perfusion and permeability responses (K{sub trans}, K{sub ep}). Results: Mice in all treatment arms survived longer than those in control, with a median survival of 35 days for SURT (P<.0001) and 30 days for RT (P=.009) and SU (P=.01) mice vs 26 days for control mice. At Day 3, ADC rise was greater with RT than without (P=.002). Sunitinib treatment reduced tumor perfusion/permeability values with mean K{sub trans} reduction of 27.6% for SU (P=.04) and 26.3% for SURT (P=.04) mice and mean K{sub ep} reduction of 38.1% for SU (P=.01) and 27.3% for SURT (P=.02) mice. The magnitude of individual mouse ADC responses at Days 3 and 7 correlated with subsequent tumor growth rate R values of ?0.878 (P=.002) and ?0.80 (P=.01), respectively. Conclusions: Early quantitative changes in diffusion and perfusion MRI measures reflect treatment responses soon after starting therapy and thereby raise the potential for these imaging biomarkers to guide adaptive and potentially individualized therapy approaches in the future.

  9. Aging Minds and Twisting Attitudes: An fMRI Investigation of Age Differences in Inhibiting Prejudice

    E-Print Network [OSTI]

    Kensinger, Elizabeth A.

    magnetic resonance imaging. All participants were also given a battery of tests to assess their executive to stigmatized individuals. Older and young adults were presented with images of stigmatized individuals (e

  10. Improvements in Low Field MRI 

    E-Print Network [OSTI]

    Ogier, Stephen E

    2013-02-01

    for this system, which has a static magnetic field in an unconventional direction. The stronger gradient allows for the selection of thin slices with RF pulses of reasonable length. The third effort was in low-noise RF coils. Typical MRI systems are enclosed...

  11. An anthropomorphic multimodality (CT/MRI) phantom prototype for end-to-end tests in radiation therapy

    E-Print Network [OSTI]

    Gallas, Raya R; Runz, Armin; Niebuhr, Nina I; Jäkel, Oliver; Greilich, Steffen

    2014-01-01

    With the increasing complexity of external beam therapy, so-called "end-to-end" tests are intended to cover all steps from therapy planning to follow-up to fulfill the high demands on quality assurance. As magnetic resonance imaging (MRI) gains growing importance in the treatment process and established phantoms (such as the Alderson head) cannot be used for those tests, novel multimodality phantoms have to be developed. Here, we present a feasibility study for such a customizable multimodality head phantom. We used a set of patient CT images as the basis for the anthropomorphic head shape. The recipient - consisting of an epoxy resin - was produced using rapid prototyping (3D printing). The phantom recipient includes a nasal air cavity, two soft tissues volumes and cranial bone. Additionally a spherical tumor volume was positioned in the center. The volumes were filled with dipotassium phosphate-based cranial bone surrogate, agarose gel, and distilled water. The tumor volume was filled with normoxic dosimetr...

  12. The MagLab's ultra-wide-bore (105mm) 21.1T NMR/MRI magnet provides an opportunity to use low gamma, low

    E-Print Network [OSTI]

    McQuade, D. Tyler

    The MagLab's ultra-wide-bore (105mm) 21.1T NMR/MRI magnet provides an opportunity to use low gamma, low sensitive nuclei for MR imaging. The potential of nuclei such as chlorine remains largely and the capability of MRI at ultra high magnetic fields to observe glioma. The finding of an increased concentration

  13. Surface Plasmon Resonance (SPR) Reflectance Imaging: A Label-Free/Real-Time Mapping of Microscale Mixture Concentration Fields (Water+Ethanol)

    E-Print Network [OSTI]

    Kihm, IconKenneth David

    Mixture Concentration Fields (Water+Ethanol) Iltai Kim and Kenneth D. Kihm Department of Mechanical (water+ethanol) concentration fields with surface plasmon resonance (SPR) reflectance technique based the refractive index and mixture concentration fields. The presented results show that ethanol penetrates

  14. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Print Magnetism is useful for many devices and techniques, from electric motors and computer hard drives to magnetic resonance imaging used in medicine. By studying...

  15. Scanning tunneling spectroscopy of unoccupied surface resonances

    E-Print Network [OSTI]

    Persson, Mats

    - induced series, produced when an electron is trapped in a potential well define* *d by the image Scanning tunneling spectroscopy of unoccupied surface resonances at free-electron-like metal surfaces. T. Fond'eny, S

  16. Studying MRI acquisition protocols of sustained sounds with a multimodal acquisition system

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    system which utilizes infrared emit- ting diodes (IREDs) requires that the sensors to be visible from a multimodal acquisition system which uses electromagnetogra- phy sensors to locate the US probe a millimetric accuracy 3D MRI images of the vocal tract have enabled more accurate evaluations of vocal tract

  17. Automated fibroglandular tissue segmentation and volumetric density estimation in breast MRI using an atlas-aided fuzzy C-means method

    SciTech Connect (OSTI)

    Wu, Shandong; Weinstein, Susan P.; Conant, Emily F.; Kontos, Despina

    2013-12-15

    Purpose: Breast magnetic resonance imaging (MRI) plays an important role in the clinical management of breast cancer. Studies suggest that the relative amount of fibroglandular (i.e., dense) tissue in the breast as quantified in MR images can be predictive of the risk for developing breast cancer, especially for high-risk women. Automated segmentation of the fibroglandular tissue and volumetric density estimation in breast MRI could therefore be useful for breast cancer risk assessment. Methods: In this work the authors develop and validate a fully automated segmentation algorithm, namely, an atlas-aided fuzzy C-means (FCM-Atlas) method, to estimate the volumetric amount of fibroglandular tissue in breast MRI. The FCM-Atlas is a 2D segmentation method working on a slice-by-slice basis. FCM clustering is first applied to the intensity space of each 2D MR slice to produce an initial voxelwise likelihood map of fibroglandular tissue. Then a prior learned fibroglandular tissue likelihood atlas is incorporated to refine the initial FCM likelihood map to achieve enhanced segmentation, from which the absolute volume of the fibroglandular tissue (|FGT|) and the relative amount (i.e., percentage) of the |FGT| relative to the whole breast volume (FGT%) are computed. The authors' method is evaluated by a representative dataset of 60 3D bilateral breast MRI scans (120 breasts) that span the full breast density range of the American College of Radiology Breast Imaging Reporting and Data System. The automated segmentation is compared to manual segmentation obtained by two experienced breast imaging radiologists. Segmentation performance is assessed by linear regression, Pearson's correlation coefficients, Student's pairedt-test, and Dice's similarity coefficients (DSC). Results: The inter-reader correlation is 0.97 for FGT% and 0.95 for |FGT|. When compared to the average of the two readers’ manual segmentation, the proposed FCM-Atlas method achieves a correlation ofr = 0.92 for FGT% and r = 0.93 for |FGT|, and the automated segmentation is not statistically significantly different (p = 0.46 for FGT% and p = 0.55 for |FGT|). The bilateral correlation between left breasts and right breasts for the FGT% is 0.94, 0.92, and 0.95 for reader 1, reader 2, and the FCM-Atlas, respectively; likewise, for the |FGT|, it is 0.92, 0.92, and 0.93, respectively. For the spatial segmentation agreement, the automated algorithm achieves a DSC of 0.69 ± 0.1 when compared to reader 1 and 0.61 ± 0.1 for reader 2, respectively, while the DSC between the two readers’ manual segmentation is 0.67 ± 0.15. Additional robustness analysis shows that the segmentation performance of the authors' method is stable both with respect to selecting different cases and to varying the number of cases needed to construct the prior probability atlas. The authors' results also show that the proposed FCM-Atlas method outperforms the commonly used two-cluster FCM-alone method. The authors' method runs at ?5 min for each 3D bilateral MR scan (56 slices) for computing the FGT% and |FGT|, compared to ?55 min needed for manual segmentation for the same purpose. Conclusions: The authors' method achieves robust segmentation and can serve as an efficient tool for processing large clinical datasets for quantifying the fibroglandular tissue content in breast MRI. It holds a great potential to support clinical applications in the future including breast cancer risk assessment.

  18. Longitudinal, intermodality registration of quantitative breast PET and MRI data acquired before and during neoadjuvant chemotherapy: Preliminary results

    SciTech Connect (OSTI)

    Atuegwu, Nkiruka C.; Williams, Jason M.; Li, Xia; Arlinghaus, Lori R.; Abramson, Richard G.; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2675; Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6838 ; Chakravarthy, A. Bapsi; Abramson, Vandana G.; Yankeelov, Thomas E.

    2014-05-15

    Purpose: The authors propose a method whereby serially acquired DCE-MRI, DW-MRI, and FDG-PET breast data sets can be spatially and temporally coregistered to enable the comparison of changes in parameter maps at the voxel level. Methods: First, the authors aligned the PET and MR images at each time point rigidly and nonrigidly. To register the MR images longitudinally, the authors extended a nonrigid registration algorithm by including a tumor volume-preserving constraint in the cost function. After the PET images were aligned to the MR images at each time point, the authors then used the transformation obtained from the longitudinal registration of the MRI volumes to register the PET images longitudinally. The authors tested this approach on ten breast cancer patients by calculating a modified Dice similarity of tumor size between the PET and MR images as well as the bending energy and changes in the tumor volume after the application of the registration algorithm. Results: The median of the modified Dice in the registered PET and DCE-MRI data was 0.92. For the longitudinal registration, the median tumor volume change was ?0.03% for the constrained algorithm, compared to ?32.16% for the unconstrained registration algorithms (p = 8 × 10{sup ?6}). The medians of the bending energy were 0.0092 and 0.0001 for the unconstrained and constrained algorithms, respectively (p = 2.84 × 10{sup ?7}). Conclusions: The results indicate that the proposed method can accurately spatially align DCE-MRI, DW-MRI, and FDG-PET breast images acquired at different time points during therapy while preventing the tumor from being substantially distorted or compressed.

  19. SU-D-18C-01: A Novel 4D-MRI Technology Based On K-Space Retrospective Sorting

    SciTech Connect (OSTI)

    Liu, Y; Yin, F; Cai, J

    2014-06-01

    Purpose: Current 4D-MRI techniques lack sufficient temporal/spatial resolution and consistent tumor contrast. To overcome these limitations, this study presents the development and initial evaluation of an entirely new framework of 4D-MRI based on k-space retrospective sorting. Methods: An important challenge of the proposed technique is to determine the number of repeated scans(NR) required to obtain sufficient k-space data for 4D-MRI. To do that, simulations using 29 cancer patients' respiratory profiles were performed to derive the relationship between data acquisition completeness(Cp) and NR, also relationship between NR(Cp=95%) and the following factors: total slice(NS), respiratory phase bin length(Lb), frame rate(fr), resolution(R) and image acquisition starting-phase(P0). To evaluate our technique, a computer simulation study on a 4D digital human phantom (XCAT) were conducted with regular breathing (fr=0.5Hz; R=256×256). A 2D echo planer imaging(EPI) MRI sequence were assumed to acquire raw k-space data, with respiratory signal and acquisition time for each k-space data line recorded simultaneously. K-space data was re-sorted based on respiratory phases. To evaluate 4D-MRI image quality, tumor trajectories were measured and compared with the input signal. Mean relative amplitude difference(D) and cross-correlation coefficient(CC) are calculated. Finally, phase-sharing sliding window technique was applied to investigate the feasibility of generating ultra-fast 4D-MRI. Result: Cp increased with NR(Cp=100*[1-exp(-0.19*NR)], when NS=30, Lb=100%/6). NR(Cp=95%) was inversely-proportional to Lb (r=0.97), but independent of other factors. 4D-MRI on XCAT demonstrated highly accurate motion information (D=0.67%, CC=0.996) with much less artifacts than those on image-based sorting 4D-MRI. Ultra-fast 4D-MRI with an apparent temporal resolution of 10 frames/second was reconstructed using the phase-sharing sliding window technique. Conclusions: A novel 4D-MRI technology based on k-space sorting has been successfully developed and evaluated on the digital phantom. Framework established can be applied to a variety of MR sequences, showing great promises to develop the optimal 4D-MRI technique for many radiation therapy applications. NIH (1R21CA165384-01A1)

  20. MRI Ventures | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View NewTexas:Montezuma,Information MHKMHK5 < MHKKemblaSolar Jump to: navigation, searchMRI

  1. Initial PET Performance Evaluation of a Preclinical Insert for PET/MRI with Digital SiPM Technology

    E-Print Network [OSTI]

    Schug, David; Weissler, Bjoern; Gebhardt, Pierre; Goldschmidt, Benjamin; Wehner, Jakob; Dueppenbecker, Peter Michael; Salomon, Andre; Hallen, Patrick; Kiessling, Fabian; Schulz, Volkmar

    2015-01-01

    Hyperion-IID is a positron emission tomography (PET) insert which allows simultaneous operation in a clinical magnetic resonance imaging (MRI) scanner. To read out the scintillation light of the employed LYSO crystal arrays with a pitch of 1 mm pitch and 12 mm in height, digital silicon photomultipliers (DPC 3200-22, Philips Digital Photon Counting) (DPC) are used. The basic PET performance in terms of energy resolution, coincidence resolution time (CRT) and sensitivity as a function of operating parameters, such as the operating temperature, the applied overvoltage, activity and configuration parameters of the DPCs, were evaluated on system level. The measured energy resolution did not show a large dependency on the selected parameters and is in the range of 12.4-12.9% for low activities and degrades to ~13.6% at activities of ~100 MBq. The CRT strongly depends on the selected trigger scheme (trig) of the DPCs. We measured approximately 260 ps, 440 ps, 540 ps and 1300 ps for trig 1-4, respectively. The trues...

  2. Prediction of daily food intake as a function of measurement modality and restriction status

    E-Print Network [OSTI]

    Giuliani, NR; Tomiyama, AJ; Tomiyama, AJ; Mann, T; Mann, T; Berkman, ET

    2015-01-01

    a food craving regulation task during functional MRI andfunctional magnetic resonance imaging data gathered during a foodfunctional mag- netic resonance imaging (MRI), which allowed us to characterize the neural indices of food

  3. Hemangioma of the Interatrial Septum: CT and MRI Features

    SciTech Connect (OSTI)

    Hrabak-Paar, Maja; Huebner, Marisa; Stern-Padovan, Ranka; Lusic, Mario

    2011-02-15

    Hemangioma of the heart is a rare primary benign tumor mainly appearing as enhancing, homogenous, well-circumscribed mass. We report a case of a 61-year-old asymptomatic woman, whose echocardiography showed a cardiac mass, which was described as the atypical myxoma of the right atrium. For further imaging, contrast-enhanced computed tomography and cardiac magnetic resonance imaging were undertaken, which showed a tumor located in the interatrial septum with imaging characteristics of hemangioma. In the literature, cardiac hemangioma is usually described as an intensely enhancing mass. In our opinion, early peripheral puddling of contrast material with filling in on delayed images is a typical pattern of its enhancement. This characteristic, in addition to high signal intensity on T2-weighted images, allows differentiation of a hemangioma from other benign and malignant tumors.

  4. McCausland Center For Brain Imaging

    E-Print Network [OSTI]

    Almor, Amit

    .mricro.com). he Siemens 3-Tesla Magnetic Resonance Imag- ing system at the McCausland Center for Brain Imaging the Palmetto Richland Memorial Hospi- tal. The Siemens 3-Tesla magnetic resonance imag- ing system is fitted brain remains one of the great scientific challenges of our generation. With approximately 100 billion

  5. Polarized Helium to Image the Lung

    E-Print Network [OSTI]

    Leduc, M; Leduc, Mich\\`{e}le; Nacher, Pierre-Jean

    2006-01-01

    The main findings of the european PHIL project (Polarised Helium to Image the Lung) are reported. State of the art optical pumping techniques for polarising ^3He gas are described. MRI methodological improvements allow dynamical ventilation images with a good resolution, ultimately limited by gas diffusion. Diffusion imaging appears as a robust method of lung diagnosis. A discussion of the potential advantage of low field MRI is presented. Selected PHIL results for emphysema are given, with the perspectives that this joint work opens up for the future of respiratory medicine.

  6. BIOSIGNAL 2002 Tagged cardiac MR images analysis

    E-Print Network [OSTI]

    Histace, Aymeric

    in cardiac tagged MR images analysis. 1 Introduction The non invasive assessment of the cardiac functionBIOSIGNAL 2002 Tagged cardiac MR images analysis A. HISTACE, L. HERMAND, C. CAVARO-MENARD LISA used by tagged MRI displays a deformable dark grid which sticks to the contraction of myocardium (fig.1

  7. Regenerative feedback resonant circuit

    SciTech Connect (OSTI)

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  8. The economic impact of physics research in the UK

    E-Print Network [OSTI]

    The economic impact of physics research in the UK: Magnetic Resonance Imaging (MRI) Scanners Case ................................................................................................. 5 2 Economic impact of MRI.................................................................7 2............................................................. 3 Box 2.1: Companies analysed to estimate the direct economic impact of MRI systems

  9. 1610 IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 11, 2012 MRI-Derived 3-D-Printed Breast Phantom

    E-Print Network [OSTI]

    Hagness, Susan C.

    1610 IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 11, 2012 MRI-Derived 3-D-Printed Breast--We propose a 3-D-printed breast phantom for use in preclinical experimental microwave imaging studies the proce- dure for generating the 3-D-printed breast phantom and present the measured dielectric properties

  10. Efficient MR Image Reconstruction for Compressed MR Imaging

    E-Print Network [OSTI]

    Huang, Junzhou

    demonstrate the superior performance of the proposed algorithm for com- pressed MR image reconstruction. 1 [1][2] show that it is possi- ble to accurately reconstruct the Magnetic Resonance (MR) images from for real MR images. Computation became the bottleneck that prevented this good model (1) from being used

  11. SU-E-J-212: Identifying Bones From MRI: A Dictionary Learnign and Sparse Regression Approach

    SciTech Connect (OSTI)

    Ruan, D; Yang, Y; Cao, M; Hu, P; Low, D [UCLA, Los Angeles, CA (United States)

    2014-06-01

    Purpose: To develop an efficient and robust scheme to identify bony anatomy based on MRI-only simulation images. Methods: MRI offers important soft tissue contrast and functional information, yet its lack of correlation to electron-density has placed it as an auxiliary modality to CT in radiotherapy simulation and adaptation. An effective scheme to identify bony anatomy is an important first step towards MR-only simulation/treatment paradigm and would satisfy most practical purposes. We utilize a UTE acquisition sequence to achieve visibility of the bone. By contrast to manual + bulk or registration-to identify bones, we propose a novel learning-based approach for improved robustness to MR artefacts and environmental changes. Specifically, local information is encoded with MR image patch, and the corresponding label is extracted (during training) from simulation CT aligned to the UTE. Within each class (bone vs. nonbone), an overcomplete dictionary is learned so that typical patches within the proper class can be represented as a sparse combination of the dictionary entries. For testing, an acquired UTE-MRI is divided to patches using a sliding scheme, where each patch is sparsely regressed against both bone and nonbone dictionaries, and subsequently claimed to be associated with the class with the smaller residual. Results: The proposed method has been applied to the pilot site of brain imaging and it has showed general good performance, with dice similarity coefficient of greater than 0.9 in a crossvalidation study using 4 datasets. Importantly, it is robust towards consistent foreign objects (e.g., headset) and the artefacts relates to Gibbs and field heterogeneity. Conclusion: A learning perspective has been developed for inferring bone structures based on UTE MRI. The imaging setting is subject to minimal motion effects and the post-processing is efficient. The improved efficiency and robustness enables a first translation to MR-only routine. The scheme generalizes to multiple tissue classes.

  12. An fMRI Investigation of Source Memory in Obsessive-Compulsive Disorder

    E-Print Network [OSTI]

    Olson, Christy Ann

    2013-12-31

    SSRI medicated and un-medicated individuals with OCD found no differences between the two groups on a comprehensive battery of neuropsychological tests (Mataix-Cols, Alonso, Pifarre, Menchon, & Vallejo, 2002); therefore, it was not expected... (Cox, 1996). 21 Scanning Parameters fMRI scanning was performed at the University of Kansas Hoglund Brain Imaging Center (HBIC), using a 3-Tesla head-only Siemens Allegra Scanner (Siemens, Erlangen, Germany) fitted with a quadrature head coil...

  13. SU-E-J-90: MRI-Based Treatment Simulation and Patient Setup for Radiation Therapy of Brain Cancer

    SciTech Connect (OSTI)

    Yang, Y; Cao, M; Han, F; Santhanam, A; Neylon, J; Gomez, C; Kaprealian, T; Sheng, K; Agazaryan, N; Low, D; Hu, P

    2014-06-01

    Purpose: Traditional radiation therapy of cancer is heavily dependent on CT. CT provides excellent depiction of the bones but lacks good soft tissue contrast, which makes contouring difficult. Often, MRIs are fused with CT to take advantage of its superior soft tissue contrast. Such an approach has drawbacks. It is desirable to perform treatment simulation entirely based on MRI. To achieve MR-based simulation for radiation therapy, bone imaging is an important challenge because of the low MR signal intensity from bone due to its ultra-short T2 and T1, which presents difficulty for both dose calculation and patient setup in terms of digitally reconstructed radiograph (DRR) generation. Current solutions will either require manual bone contouring or multiple MR scans. We present a technique to generate DRR using MRI with an Ultra Short Echo Time (UTE) sequence which is applicable to both OBI and ExacTrac 2D patient setup. Methods: Seven brain cancer patients were scanned at 1.5 Tesla using a radial UTE sequence. The sequence acquires two images at two different echo times. The two images were processed using in-house software. The resultant bone images were subsequently loaded into commercial systems to generate DRRs. Simulation and patient clinical on-board images were used to evaluate 2D patient setup with MRI-DRRs. Results: The majority bones are well visualized in all patients. The fused image of patient CT with the MR bone image demonstrates the accuracy of automatic bone identification using our technique. The generated DRR is of good quality. Accuracy of 2D patient setup by using MRI-DRR is comparable to CT-based 2D patient setup. Conclusion: This study shows the potential of DRR generation with single MR sequence. Further work will be needed on MR sequence development and post-processing procedure to achieve robust MR bone imaging for other human sites in addition to brain.

  14. 4D Flow MRI Applications for Aortic Disease

    E-Print Network [OSTI]

    Burris, NS; Hope, MD

    2015-01-01

    stress in the aorta by flow-sensitive four-dimensional-MRI.cation of collateral blood flow in coarctation of the aortaaccelerated four-dimensional flow MRI in the aorta: effect

  15. IMMEDIATE JOB OPENING MRI technical developments and applications

    E-Print Network [OSTI]

    Duong, Timothy Q.

    to study anatomy, metabolism, physiology (such as blood flow and oxygenation) and function in neurosciences Trio 5) MRI: 3T/90cm whole-body Siemens TIM Trio + AC88 high performance gradient insert 6) MRI: 3T/90

  16. Monofilament MgB? wires for MRI magnets

    E-Print Network [OSTI]

    Ling, Jiayin

    2012-01-01

    MRI magnets are useful medical devices in early detection and efficient treatment of disease or injury. Because of the significant better performance, MRI magnets are made of superconductors rather than made of copper. ...

  17. Peptide functionalized superparamagnetic iron oxide nanoparticles as MRI contrast agents

    E-Print Network [OSTI]

    Atalar, Ergin

    of abnormal tissues.2 MRI uses radiofrequency in a magnetic field as source of radiation which has no harmful

  18. A high-field 3He Metastability Exchange Optical Pumping polarizer operating in a 1.5 T medical scanner for lung MRI

    E-Print Network [OSTI]

    Collier, G; Wojna, A; G?owacz, B; Suchanek, M; Olejniczak, Z; Dohnalik, T

    2013-01-01

    After being hyperpolarized using the technique of Metastability Exchange Optical Pumping (MEOP), 3He can be used as a contrast agent for lung magnetic resonance imaging (MRI). MEOP is usually performed at low magnetic field (~ 1 mT) and low pressure (~ 1 mbar), which results in a low magnetization production rate. A delicate polarization-preserving step of compression is also required. It was demonstrated in sealed cells that high nuclear polarization values can be obtained at higher pressures with MEOP, if performed at high magnetic field (non-standard conditions). In this work the feasibility of building a high-field polarizer that operates within a commercial 1.5 T scanner was evaluated. Preliminary measurements of nuclear polarization with sealed cells filled at different 3He gas pressures (1.33 to 267 mbar) were performed. The use of an annular shape for the laser beam increased by 25 % the achievable nuclear polarization equilibrium value (Meq) at 32 and 67 mbar as compared to a Gaussian beam shape. Meq...

  19. Pore-structure determinations of silica aerogels by {sup 129}Xe NMR spectroscopy and imaging.

    SciTech Connect (OSTI)

    Gregory, D. M.; Gerald, R. E., II; Botto, R. E.; Chemistry

    1998-04-01

    Silica aerogels represent a new class of open-pore materials with pore dimensions on a scale of tens of nanometers, and are thus classified as mesoporous materials. In this work, we show that the combination of NMR spectroscopy and chemical-shift selective magnetic resonance imaging (MRI) can resolve some of the important aspects of the structure of silica aerogels. The use of xenon as a gaseous probe in combination with spatially resolved NMR techniques is demonstrated to be a powerful, new approach for characterizing the average pore structure and steady-state spatial distributions of xenon atoms in different physicochemical environments. Furthermore, dynamic NMR magnetization transfer experiments and pulsed-field gradient (PFG) measurements have been used to characterize exchange processes and diffusive motion of xenon in samples at equilibrium. In particular, this new NMR approach offers unique information and insights into the nanoscopic pore structure and microscopic morphology of aerogels and the dynamical behavior of occluded adsorbates. MRI provides spatially resolved information on the nature of the flaw regions found in these materials. Pseudo-first-order rate constants for magnetization transfer among the bulk and occluded xenon phases indicate xenon-exchange rate constants on the order of 1 s-1 for specimens having volumes of 0.03 cm3. PFG diffusion measurements show evidence of anisotropic diffusion for xenon occluded within aerogels, with nominal self-diffusivity coefficients on the order of D= 10-3cm2/s.

  20. Lensless Imaging of Magnetic Nanostructures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    28 March 2012 00:00 Magnetism is useful for many devices and techniques, from electric motors and computer hard drives to magnetic resonance imaging used in medicine. By studying...

  1. Multifrequency spin resonance in diamond

    SciTech Connect (OSTI)

    Childress, Lilian; McIntyre, Jean

    2010-09-15

    Magnetic resonance techniques provide a powerful tool for controlling spin systems, with applications ranging from quantum information processing to medical imaging. Nevertheless, the behavior of a spin system under strong excitation remains a rich dynamical problem. In this paper, we examine spin resonance of the nitrogen-vacancy center in diamond under conditions outside the regime where the usual rotating-wave approximation applies, focusing on effects of multifrequency excitation and excitation with orientation parallel to the spin quantization axis. Strong-field phenomena such as multiphoton transitions and coherent destruction of tunneling are observed in the spectra and analyzed via numerical and analytic theory. In addition to illustrating the response of a spin system to strong multifrequency excitation, these observations may inform techniques for manipulating electron-nuclear spin quantum registers.

  2. Next Generation Magnetic Resonance Imaging Contrast Agents

    E-Print Network [OSTI]

    Klemm, Piper Julia

    2012-01-01

    and environmental impact of Fe make it a promising candidate for more sustainable contrast agent development.

  3. Next Generation Magnetic Resonance Imaging Contrast Agents

    E-Print Network [OSTI]

    Klemm, Piper Julia

    2012-01-01

    were filtered over 0.45 ! m PTFE filters to remove dust andsolids through a 0.45 ! m PTFE filter the red solution wasand filtered over a 0.45 ! m PTFE filter. After evaporation

  4. Magnetic resonance imaging of plantar plate rupture

    E-Print Network [OSTI]

    Yao, L; Cracchiolo, A; Farahani, K; Seeger, LL

    1996-01-01

    had an ipsilateral hallux valgus, and five had a hammertoe8), and an ipsilateral hallux valgus (6 of 8). Patients with

  5. Neutron resonance averaging

    SciTech Connect (OSTI)

    Chrien, R.E.

    1986-10-01

    The principles of resonance averaging as applied to neutron capture reactions are described. Several illustrations of resonance averaging to problems of nuclear structure and the distribution of radiative strength in nuclei are provided. 30 refs., 12 figs.

  6. High-ResolutionReal-Time and Color-Flow MRI of Nitinol Stents M. Terashima,E. de la Pena-Almaguer,K.S. Nayak,J.M. Pauly, P.C. Yang, B.S. Hu, M.V. McConnell

    E-Print Network [OSTI]

    Nayak, Krishna

    High-ResolutionReal-Time and Color-Flow MRI of Nitinol Stents M. Terashima,E. de la Pena, but they typically impair MR imaging. Nitinol stents, in contrast, have reduced artifacts and may allow real-time MRI placed in the aorta. Nitinol stent patency was seen in vivo with both high-resolution real-time and color

  7. Ovenized microelectromechanical system (MEMS) resonator

    DOE Patents [OSTI]

    Olsson, Roy H; Wojciechowski, Kenneth; Kim, Bongsang

    2014-03-11

    An ovenized micro-electro-mechanical system (MEMS) resonator including: a substantially thermally isolated mechanical resonator cavity; a mechanical oscillator coupled to the mechanical resonator cavity; and a heating element formed on the mechanical resonator cavity.

  8. Branding and a child’s brain: an fMRI study of neural responses to logos

    E-Print Network [OSTI]

    Bruce, Amanda S.; Bruce, Jared M.; Black, William R.; Lepping, Rebecca Jo Chambers; Henry, Janice M.; Cherry, Joseph Bradley C.; Martin, Laura E.; Papa, Vlad B.; Davis, Ann M.; Brooks, William M.; Savage, Cary R.

    2012-12-14

    food and non-food logos on valence and intensity. A new sample of 17 healthy weight children were then scanned using functional magnetic resonance imaging. Food logos compared to baseline were associated with increased activation in orbitofrontal cortex...

  9. Comparative Analysis of Connection and Disconnection in the Human Brain Using Diffusion MRI: New Methods and Applications 

    E-Print Network [OSTI]

    Clayden, Jonathan D

    2008-01-01

    Diffusion magnetic resonance imaging (dmri) is a technique that can be used to examine the diffusion characteristics of water in the living brain. A recently developed application of this technique is tractography, in ...

  10. Extracting morphological networks from individual grey matter MRI scans in healthy subjects and people at high risk for schizophrenia 

    E-Print Network [OSTI]

    Tijms, Betty Marije

    2012-06-25

    Recently graph theory has been successfully applied to magnetic resonance imaging data. However, it remains unclear as to what the nodes and edges in a network should represent. This problem is particularly difficult ...

  11. DCE-MRI defined subvolumes of a brain metastatic lesion by principle component analysis and fuzzy-c-means clustering for response assessment of radiation therapy

    SciTech Connect (OSTI)

    Farjam, Reza; Tsien, Christina I.; Lawrence, Theodore S.; Cao, Yue; Department of Radiology, University of Michigan, 1500 East Medical Center Drive, Med Inn Building C478, Ann Arbor, Michigan 48109-5842; Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, Michigan 48109-2099

    2014-01-15

    Purpose: To develop a pharmacokinetic modelfree framework to analyze the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data for assessment of response of brain metastases to radiation therapy. Methods: Twenty patients with 45 analyzable brain metastases had MRI scans prior to whole brain radiation therapy (WBRT) and at the end of the 2-week therapy. The volumetric DCE images covering the whole brain were acquired on a 3T scanner with approximately 5 s temporal resolution and a total scan time of about 3 min. DCE curves from all voxels of the 45 brain metastases were normalized and then temporally aligned. A DCE matrix that is constructed from the aligned DCE curves of all voxels of the 45 lesions obtained prior to WBRT is processed by principal component analysis to generate the principal components (PCs). Then, the projection coefficient maps prior to and at the end of WBRT are created for each lesion. Next, a pattern recognition technique, based upon fuzzy-c-means clustering, is used to delineate the tumor subvolumes relating to the value of the significant projection coefficients. The relationship between changes in different tumor subvolumes and treatment response was evaluated to differentiate responsive from stable and progressive tumors. Performance of the PC-defined tumor subvolume was also evaluated by receiver operating characteristic (ROC) analysis in prediction of nonresponsive lesions and compared with physiological-defined tumor subvolumes. Results: The projection coefficient maps of the first three PCs contain almost all response-related information in DCE curves of brain metastases. The first projection coefficient, related to the area under DCE curves, is the major component to determine response while the third one has a complimentary role. In ROC analysis, the area under curve of 0.88 ± 0.05 and 0.86 ± 0.06 were achieved for the PC-defined and physiological-defined tumor subvolume in response assessment. Conclusions: The PC-defined subvolume of a brain metastasis could predict tumor response to therapy similar to the physiological-defined one, while the former is determined more rapidly for clinical decision-making support.

  12. Resonant and non-resonant magnetic scattering

    SciTech Connect (OSTI)

    McWhan, D.B.; Hastings, J.B.; Kao, C.C.; Siddons, D.P.

    1991-12-31

    The tunability and the polarization of synchrotron radiation open upon new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and thy fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation.

  13. Resonant and non-resonant magnetic scattering

    SciTech Connect (OSTI)

    McWhan, D.B.; Hastings, J.B.; Kao, C.C.; Siddons, D.P.

    1991-01-01

    The tunability and the polarization of synchrotron radiation open upon new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and thy fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation.

  14. Figure 1. A result from a 14-year old subject with sleep related breathing disorder. (a,b) Axial MR image frames representing that there is (a) no apneic event and (b) central apnea. A marked reduction of the airway cross-sectional area is observed in (b)

    E-Print Network [OSTI]

    Southern California, University of

    imaging (MRI) is non-invasive, involves no ionizing radiation, and can provide detailed anatomical gradient amplifier overheating and radiofrequency tissue heating, 3) facilitating patient comfort to enable

  15. ACCELERATING ITERATIVE FIELD-COMPENSATED MR IMAGE RECONSTRUCTION ON GPUS

    E-Print Network [OSTI]

    Hwu, Wen-mei W.

    ACCELERATING ITERATIVE FIELD-COMPENSATED MR IMAGE RECONSTRUCTION ON GPUS Yue Zhuo1 , Xiao-Long Wu2 , Justin P. Haldar2 , Wen-mei Hwu2 , Zhi-pei Liang2 , Bradley P. Sutton1 1 Department of Bioengineering for iterative MR image reconstruction using Graphics Processing Units (GPU). In MRI, iterative reconstruction

  16. Video Toroid Cavity Imager

    DOE Patents [OSTI]

    Gerald, Rex E. II; Sanchez, Jairo; Rathke, Jerome W.

    2004-08-10

    A video toroid cavity imager for in situ measurement of electrochemical properties of an electrolytic material sample includes a cylindrical toroid cavity resonator containing the sample and employs NMR and video imaging for providing high-resolution spectral and visual information of molecular characteristics of the sample on a real-time basis. A large magnetic field is applied to the sample under controlled temperature and pressure conditions to simultaneously provide NMR spectroscopy and video imaging capabilities for investigating electrochemical transformations of materials or the evolution of long-range molecular aggregation during cooling of hydrocarbon melts. The video toroid cavity imager includes a miniature commercial video camera with an adjustable lens, a modified compression coin cell imager with a fiat circular principal detector element, and a sample mounted on a transparent circular glass disk, and provides NMR information as well as a video image of a sample, such as a polymer film, with micrometer resolution.

  17. Resonant thermonuclear reaction rate

    SciTech Connect (OSTI)

    Haubold, H.J.; Mathai, A.M.

    1986-08-01

    Basic physical principles for the resonant and nonresonant thermonuclear reaction rates are applied to find their standard representations for nuclear astrophysics. Closed-form representations for the resonant reaction rate are derived in terms of Meijer's G-italic-function. Analytic representations of the resonant and nonresonant nuclear reaction rates are compared and the appearance of Meijer's G-italic-function is discussed in physical terms.

  18. Thermal Resonance Fusion

    E-Print Network [OSTI]

    Bao-Guo Dong

    2015-07-07

    We first show a possible mechanism to create a new type of nuclear fusion, thermal resonance fusion, i.e. low energy nuclear fusion with thermal resonance of light nuclei or atoms, such as deuterium or tritium. The fusion of two light nuclei has to overcome the Coulomb barrier between these two nuclei to reach up to the interacting region of nuclear force. We found nuclear fusion could be realized with thermal vibrations of crystal lattice atoms coupling with light atoms at low energy by resonance to overcome this Coulomb barrier. Thermal resonances combining with tunnel effects can greatly enhance the probability of the deuterium fusion to the detectable level. Our low energy nuclear fusion mechanism research - thermal resonance fusion mechanism results demonstrate how these light nuclei or atoms, such as deuterium, can be fused in the crystal of metal, such as Ni or alloy, with synthetic thermal vibrations and resonances at different modes and energies experimentally. The probability of tunnel effect at different resonance energy given by the WKB method is shown that indicates the thermal resonance fusion mode, especially combined with the tunnel effect, is possible and feasible. But the penetrating probability decreases very sharply when the input resonance energy decreases less than 3 keV, so for thermal resonance fusion, the key point is to increase the resonance peak or make the resonance sharp enough to the acceptable energy level by the suitable compound catalysts, and it is better to reach up more than 3 keV to make the penetrating probability larger than 10^{-10}.

  19. ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. X, NO. X, JANUARY 2013 1 MRI-derived 3D-printed breast phantom for

    E-Print Network [OSTI]

    Van Veen, Barry D.

    ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. X, NO. X, JANUARY 2013 1 MRI-derived 3D-printed--We propose a 3D-printed breast phantom for use in pre-clinical experimental microwave imaging studies the procedure for generating the 3D-printed breast phantom and present the measured dielectric properties

  20. 9.71 Functional MRI of High-Level Vision, Fall 2004

    E-Print Network [OSTI]

    Kanwisher, Nancy

    Covers the basics of fMRI, the strengths and limitations of fMRI compared to other techniques, and the design and analysis of fMRI experiments, focusing primarily on experiments on high-level vision. Upon completion, ...

  1. Advances in MRI to probe the functional and structural network of the macaque brain

    E-Print Network [OSTI]

    Khachaturian, Mark Haig, 1979-

    2007-01-01

    Diffusion MRI and fMRI have provided neuroscientists with non-invasive tools to probe the functional and structural network of the brain. Diffusion MRI is a neuroimaging technique capable of measuring the diffusion of water ...

  2. Ultra-low field MRI of prostate cancer using SQUID detection

    E-Print Network [OSTI]

    Busch, Sarah Elizabeth

    2011-01-01

    coil. Chapter 3 3 Ultra low field MRI 3.1 Polarization TheUltra-low field MRI of prostate cancer using SQUID detectionSteven Conolly Spring 2011 Ultra-low field MRI of prostate

  3. 9.71 Functional MRI of High-Level Vision, Fall 2002

    E-Print Network [OSTI]

    Kanwisher, Nancy

    Covers the basics of fMRI, the strengths and limitations of fMRI compared to other techniques, and the design and analysis of fMRI experiments, focusing primarily on experiments on high-level vision. Upon completion, ...

  4. Helioseismology The Resonant Sun

    E-Print Network [OSTI]

    Helioseismology The Resonant Sun Professor Bill Chaplin, School of Physics & Astronomy University Eddington #12;The Unseen Interior ''At first sight it would seem that the deep interior of the sun and stars;Overview What are resonant oscillations of the Sun? How do we observe the oscillations? What can we learn

  5. Resonant snubber inverter

    DOE Patents [OSTI]

    Lai, J.S.; Young, R.W. Sr.; Chen, D.; Scudiere, M.B.; Ott, G.W. Jr.; White, C.P.; McKeever, J.W.

    1997-06-24

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter. 14 figs.

  6. Resonant snubber inverter

    DOE Patents [OSTI]

    Lai, Jih-Sheng (Knoxville, TN); Young, Sr., Robert W. (Oak Ridge, TN); Chen, Daoshen (Knoxville, TN); Scudiere, Matthew B. (Oak Ridge, TN); Ott, Jr., George W. (Knoxville, TN); White, Clifford P. (Knoxville, TN); McKeever, John W. (Oak Ridge, TN)

    1997-01-01

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  7. NSF's MAJOR RESEARCH INSTRUMENTATION (MRI) Program The Major Research Instrumentation Program (MRI) serves to increase access to shared scientific and

    E-Print Network [OSTI]

    Finley Jr., Russell L.

    NSF's MAJOR RESEARCH INSTRUMENTATION (MRI) Program The Major Research Instrumentation Program (MRI) serves to increase access to shared scientific and engineering instruments for research and research to acquire major instrumentation that supports the research and research training goals of the organization

  8. Near Infrared Surface Plasmon Resonance Phase Imaging and Nanoparticle-Enhanced Surface Plasmon Resonance Phase Imaging

    E-Print Network [OSTI]

    utilized a near-infrared 860 nm light emitting diode (LED) light source and a wedge depolarizer to create

  9. Tunable multiwalled nanotube resonator

    DOE Patents [OSTI]

    Zettl, Alex K. (Kensington, CA); Jensen, Kenneth J. (Berkeley, CA); Girit, Caglar (Albany, CA); Mickelson, William E. (San Francisco, CA); Grossman, Jeffrey C. (Berkeley, CA)

    2011-03-29

    A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

  10. Tunable multiwalled nanotube resonator

    DOE Patents [OSTI]

    Jensen, Kenneth J; Girit, Caglar O; Mickelson, William E; Zettl, Alexander K; Grossman, Jeffrey C

    2013-11-05

    A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

  11. Modeling of electrodes and implantable pulse generator cases for the analysis of implant tip heating under MR imaging

    SciTech Connect (OSTI)

    Acikel, Volkan Atalar, Ergin; Uslubas, Ali

    2015-07-15

    Purpose: The authors’ purpose is to model the case of an implantable pulse generator (IPG) and the electrode of an active implantable medical device using lumped circuit elements in order to analyze their effect on radio frequency induced tissue heating problem during a magnetic resonance imaging (MRI) examination. Methods: In this study, IPG case and electrode are modeled with a voltage source and impedance. Values of these parameters are found using the modified transmission line method (MoTLiM) and the method of moments (MoM) simulations. Once the parameter values of an electrode/IPG case model are determined, they can be connected to any lead, and tip heating can be analyzed. To validate these models, both MoM simulations and MR experiments were used. The induced currents on the leads with the IPG case or electrode connections were solved using the proposed models and the MoTLiM. These results were compared with the MoM simulations. In addition, an electrode was connected to a lead via an inductor. The dissipated power on the electrode was calculated using the MoTLiM by changing the inductance and the results were compared with the specific absorption rate results that were obtained using MoM. Then, MRI experiments were conducted to test the IPG case and the electrode models. To test the IPG case, a bare lead was connected to the case and placed inside a uniform phantom. During a MRI scan, the temperature rise at the lead was measured by changing the lead length. The power at the lead tip for the same scenario was also calculated using the IPG case model and MoTLiM. Then, an electrode was connected to a lead via an inductor and placed inside a uniform phantom. During a MRI scan, the temperature rise at the electrode was measured by changing the inductance and compared with the dissipated power on the electrode resistance. Results: The induced currents on leads with the IPG case or electrode connection were solved for using the combination of the MoTLiM and the proposed lumped circuit models. These results were compared with those from the MoM simulations. The mean square error was less than 9%. During the MRI experiments, when the IPG case was introduced, the resonance lengths were calculated to have an error less than 13%. Also the change in tip temperature rise at resonance lengths was predicted with less than 4% error. For the electrode experiments, the value of the matching impedance was predicted with an error less than 1%. Conclusions: Electrical models for the IPG case and electrode are suggested, and the method is proposed to determine the parameter values. The concept of matching of the electrode to the lead is clarified using the defined electrode impedance and the lead Thevenin impedance. The effect of the IPG case and electrode on tip heating can be predicted using the proposed theory. With these models, understanding the tissue heating due to the implants becomes easier. Also, these models are beneficial for implant safety testers and designers. Using these models, worst case conditions can be determined and the corresponding implant test experiments can be planned.

  12. Electron contamination modeling and reduction in a 1 T open bore inline MRI-linac system

    SciTech Connect (OSTI)

    Oborn, B. M.; Kolling, S.; Metcalfe, P. E.; Crozier, S.; Litzenberg, D. W.; Keall, P. J.

    2014-05-15

    Purpose: A potential side effect of inline MRI-linac systems is electron contamination focusing causing a high skin dose. In this work, the authors reexamine this prediction for an open bore 1 T MRI system being constructed for the Australian MRI-Linac Program. The efficiency of an electron contamination deflector (ECD) in purging electron contamination from the linac head is modeled, as well as the impact of a helium gas region between the deflector and phantom surface for lowering the amount of air-generated contamination. Methods: Magnetic modeling of the 1 T MRI was used to generate 3D magnetic field maps both with and without the presence of an ECD located immediately below the MLC’s. Forty-seven different ECD designs were modeled and for each the magnetic field map was imported into Geant4 Monte Carlo simulations including the linac head, ECD, and a 30 × 30 × 30 cm{sup 3} water phantom located at isocenter. For the first generation system, the x-ray source to isocenter distance (SID) will be 160 cm, resulting in an 81.2 cm long air gap from the base of the ECD to the phantom surface. The first 71.2 cm was modeled as air or helium gas, with the latter encased between two windows of 50 ?m thick high density polyethlyene. 2D skin doses (at 70 ?m depth) were calculated across the phantom surface at 1 × 1 mm{sup 2} resolution for 6 MV beams of field size of 5 × 5, 10 × 10, and 20 × 20 cm{sup 2}. Results: The skin dose was predicted to be of similar magnitude as the generic systems modeled in previous work, 230% to 1400% ofD {sub max} for 5 × 5 to 20 × 20 cm{sup 2}, respectively. Inclusion of the ECD introduced a nonuniformity to the MRI imaging field that ranged from ?20 to ?140 ppm while the net force acting on the ECD ranged from ?151 N to ?1773 N. Various ECD designs were 100% efficient at purging the electron contamination into the ECD magnet banks; however, a small percentage were scattered back into the beam and continued to the phantom surface. Replacing a large portion of the extended air-column between the ECD and phantom surface with helium gas is a key element as it significantly minimized the air-generated contamination. When using an optimal ECD and helium gas region, the 70 ?m skin dose is predicted to increase moderately inside a small hot spot over that of the case with no magnetic field present for the jaw defined square beams examined here. These increases include from 12% to 40% of D {sub max} for 5 × 5 cm{sup 2}, 18% to 55% of D {sub max} for 10 × 10 cm{sup 2}, and from 23% to 65% of D {sub max} for 20 × 20 cm{sup 2}. Conclusions: Coupling an efficient ECD and helium gas region below the MLCs in the 160 cm isocenter MRI-linac system is predicted to ameliorate the impact electron contamination focusing has on skin dose increases. An ECD is practical as its impact on the MRI imaging distortion is correctable, and the mechanical forces acting on it manageable from an engineering point of view.

  13. Imaging Mechanical Vibrations in Suspended Graphene Sheets

    E-Print Network [OSTI]

    McEuen, Paul L.

    Imaging Mechanical Vibrations in Suspended Graphene Sheets D. Garcia-Sanchez,, A. M. van der Zande was electrostatically driven at resonance using applied radio frequency voltages. The mechanical vibrations were of the shape of the mechanical eigenmodes. In as many as half the resonators measured, we observed a new class

  14. Nuclear Resonance Fluorescence for Nuclear Materials Assay

    E-Print Network [OSTI]

    Quiter, Brian Joseph

    2010-01-01

    Potential of Nuclear Resonance Fluorescence . . . . . . . .2.9.1 Nuclear ThomsonSections . . . . . . . . . . . . . . . Nuclear Resonance

  15. Micro-machined resonator

    DOE Patents [OSTI]

    Godshall, N.A.; Koehler, D.R.; Liang, A.Y.; Smith, B.K.

    1993-03-30

    A micro-machined resonator, typically quartz, with upper and lower micro-machinable support members, or covers, having etched wells which may be lined with conductive electrode material, between the support members is a quartz resonator having an energy trapping quartz mesa capacitively coupled to the electrode through a diaphragm; the quartz resonator is supported by either micro-machined cantilever springs or by thin layers extending over the surfaces of the support. If the diaphragm is rigid, clock applications are available, and if the diaphragm is resilient, then transducer applications can be achieved. Either the thin support layers or the conductive electrode material can be integral with the diaphragm. In any event, the covers are bonded to form a hermetic seal and the interior volume may be filled with a gas or may be evacuated. In addition, one or both of the covers may include oscillator and interface circuitry for the resonator.

  16. Resonant dielectric metamaterials

    DOE Patents [OSTI]

    Loui, Hung; Carroll, James; Clem, Paul G; Sinclair, Michael B

    2014-12-02

    A resonant dielectric metamaterial comprises a first and a second set of dielectric scattering particles (e.g., spheres) having different permittivities arranged in a cubic array. The array can be an ordered or randomized array of particles. The resonant dielectric metamaterials are low-loss 3D isotropic materials with negative permittivity and permeability. Such isotropic double negative materials offer polarization and direction independent electromagnetic wave propagation.

  17. Injector with integrated resonator

    DOE Patents [OSTI]

    Johnson, Thomas Edward; Ziminsky, Willy Steve; York, William David; Stevenson, Christian Xavier

    2014-07-29

    The system may include a turbine engine. The turbine engine may include a fuel nozzle. The fuel nozzle may include an air path. The fuel nozzle may also include a fuel path such that the fuel nozzle is in communication with a combustion zone of the turbine engine. Furthermore, the fuel nozzle may include a resonator. The resonator may be disposed in the fuel nozzle directly adjacent to the combustion zone.

  18. Resonant nonlinear ultrasound spectroscopy

    DOE Patents [OSTI]

    Johnson, Paul A. (Santa Fe, NM); TenCate, James A. (Los Alamos, NM); Guyer, Robert A. (Amherst, MA); Van Den Abeele, Koen E. A. (Sint-Niklaas, BE)

    2001-01-01

    Components with defects are identified from the response to strains applied at acoustic and ultrasound frequencies. The relative resonance frequency shift .vertline..DELTA..function./.function..sub.0.vertline., is determined as a function of applied strain amplitude for an acceptable component, where .function..sub.0 is the frequency of the resonance peak at the lowest amplitude of applied strain and .DELTA..function. is the frequency shift of the resonance peak of a selected mode to determine a reference relationship. Then, the relative resonance frequency shift .vertline..DELTA..function./.function..sub.0 is determined as a function of applied strain for a component under test, where fo .function..sub.0 the frequency of the resonance peak at the lowest amplitude of applied strain and .DELTA..function. is the frequency shift of the resonance peak to determine a quality test relationship. The reference relationship is compared with the quality test relationship to determine the presence of defects in the component under test.

  19. Thermal Resonance Fusion

    E-Print Network [OSTI]

    Dong, Bao-Guo

    2015-01-01

    We first show a possible mechanism to create a new type of nuclear fusion, thermal resonance fusion, i.e. low energy nuclear fusion with thermal resonance of light nuclei or atoms, such as deuterium or tritium. The fusion of two light nuclei has to overcome the Coulomb barrier between these two nuclei to reach up to the interacting region of nuclear force. We found nuclear fusion could be realized with thermal vibrations of crystal lattice atoms coupling with light atoms at low energy by resonance to overcome this Coulomb barrier. Thermal resonances combining with tunnel effects can greatly enhance the probability of the deuterium fusion to the detectable level. Our low energy nuclear fusion mechanism research - thermal resonance fusion mechanism results demonstrate how these light nuclei or atoms, such as deuterium, can be fused in the crystal of metal, such as Ni or alloy, with synthetic thermal vibrations and resonances at different modes and energies experimentally. The probability of tunnel effect at dif...

  20. Signals & Systems Prof. Mark Fowler

    E-Print Network [OSTI]

    Fowler, Mark

    monitoring, ultrasound imaging, magnetic resonance imaging (MRI) Image Processing 3D animation, image positioning in disk drives, laser control (e.g., printers, CD/DVD drives), engine & motor control, robots

  1. fMRI Insight or Inhibition? Investigating the impact of the fMRI Environment upon behavioural performance in the popular verbal n-back task 

    E-Print Network [OSTI]

    Thorp, Rachael

    2008-06-27

    Are current fMRI research findings misleading about the nature of human working memory? Though increasingly popular as a technique for studying human working memory, fMRI studies have typically failed to account for any ...

  2. MgB[subscript 2] Coils for MRI Applications

    E-Print Network [OSTI]

    Yao, Weijun

    In this paper, we report our progress in the development of a low cost, liquid-helium-free MgB2 superconducting MRI magnet. Several technical issues related to the construction of such a magnet to operate in persistent ...

  3. Pharmaco-fMRI: a New Clinical Tool to Discover

    E-Print Network [OSTI]

    California at San Diego, University of

    ­ Lorazepam and emotional face processing ­ Lorazepam and risk-taking 5. fMRI study with high trait anxious) and basic sciences. ­ Need for new clinical endpoints. · Pipeline problem: ­ "Our pipeline is rich

  4. Phase-based regional oxygen metabolism (PROM) using MRI

    E-Print Network [OSTI]

    Fan, Audrey Peiwen

    Venous oxygen saturation (Yv) in cerebral veins and the cerebral metabolic rate of oxygen (CMRO2) are important indicators for brain function and disease. Although MRI has been used for global measurements of these parameters, ...

  5. Technical Note Functional MRI of the Thoracic Spinal Cord During

    E-Print Network [OSTI]

    Smith, Stephen D.

    spinal cord using a HASTE sequence on a 3 Tesla MRI system. Results: Signal increases were observed neuronal activity related to both sensory and motor function. Although most of these studies have focused

  6. Resonant ultrasound spectrometer

    DOE Patents [OSTI]

    Migliori, Albert (Santa Fe, NM); Visscher, William M. (Los Alamos, NM); Fisk, Zachary (Santa Fe, NM)

    1990-01-01

    An ultrasound resonant spectrometer determines the resonant frequency spectrum of a rectangular parallelepiped sample of a high dissipation material over an expected resonant response frequency range. A sample holder structure grips corners of the sample between piezoelectric drive and receive transducers. Each transducer is mounted on a membrane for only weakly coupling the transducer to the holder structure and operatively contacts a material effective to remove system resonant responses at the transducer from the expected response range. i.e., either a material such as diamond to move the response frequencies above the range or a damping powder to preclude response within the range. A square-law detector amplifier receives the response signal and retransmits the signal on an isolated shield of connecting cabling to remove cabling capacitive effects. The amplifier also provides a substantially frequency independently voltage divider with the receive transducer. The spectrometer is extremely sensitive to enable low amplitude resonance to be detected for use in calculating the elastic constants of the high dissipation sample.

  7. Methods to assess changes in human brain structure across the lifecourse 

    E-Print Network [OSTI]

    Dickie, David Alexander

    2014-11-28

    Human brain structure can be measured across the lifecourse (“in vivo”) with magnetic resonance imaging (MRI). MRI data are often used to create “atlases” and statistical models of brain structure across the lifecourse. ...

  8. For more information, please contact Prof. Frank Fisher at Frank.Fisher@stevens.edu or 201-216-8913 STEVENS INSTITUTE OF TECHNOLOGY

    E-Print Network [OSTI]

    Fisher, Frank

    , Time: NOON Enabling Technologies for Robotic MRI-Guided Interventional Procedures Gregory S. Fischer Johns Hopkins University Magnetic Resonance Imaging (MRI) can provide high-quality 3D visualization the systems requirements development, robotic system design, controller design, system integration

  9. Quartz resonator processing system

    DOE Patents [OSTI]

    Peters, Roswell D. M. (Rustburg, VA)

    1983-01-01

    Disclosed is a single chamber ultra-high vacuum processing system for the oduction of hermetically sealed quartz resonators wherein electrode metallization and sealing are carried out along with cleaning and bake-out without any air exposure between the processing steps. The system includes a common vacuum chamber in which is located a rotatable wheel-like member which is adapted to move a plurality of individual component sets of a flat pack resonator unit past discretely located processing stations in said chamber whereupon electrode deposition takes place followed by the placement of ceramic covers over a frame containing a resonator element and then to a sealing stage where a pair of hydraulic rams including heating elements effect a metallized bonding of the covers to the frame.

  10. Magnetostrictive resonance excitation

    DOE Patents [OSTI]

    Schwarz, Ricardo B. (Los Alamos, NM); Kuokkala, Veli-Tapani (Tampere, FI)

    1992-01-01

    The resonance frequency spectrum of a magnetostrictive sample is remotely determined by exciting the magnetostrictive property with an oscillating magnetic field. The permeability of a magnetostrictive material and concomitant coupling with a detection coil varies with the strain in the material whereby resonance responses of the sample can be readily detected. A suitable sample may be a magnetostrictive material or some other material having at least one side coated with a magnetostrictive material. When the sample is a suitable shape, i.e., a cube, rectangular parallelepiped, solid sphere or spherical shell, the elastic moduli or the material can be analytically determined from the measured resonance frequency spectrum. No mechanical transducers are required and the sample excitation is obtained without contact with the sample, leading to highly reproducible results and a measurement capability over a wide temperature range, e.g. from liquid nitrogen temperature to the Curie temperature of the magnetostrictive material.

  11. Performing temperature feedback controlled tissue photo-coagulation using magnetic resonance thermometry 

    E-Print Network [OSTI]

    Sampath, Smita

    1999-01-01

    controlled photo-coagulation using magnetic resonance imaging as the non-invasive means of temperature feedback. The desired coagulation depth was controlled at a constant temperature of 40 degrees for different amounts of time and the actual coagulation...

  12. Technical Note Intracoronary MR Imaging Using a 0.014-Inch MR

    E-Print Network [OSTI]

    Atalar, Ergin

    and Methods: A custom gold/sliver/Nitinol/ MP35N-based, 0.014-inch MRIG was manufactured. To test its with this technique is that the x-ray contrast agent can outline only the vessel lumen. Magnetic res- onance imaging (MRI), which provides not only anatom- ical images of the heart but also functional as well

  13. Localization of Fiducial Skin Markers in MR Images using Correlation Pattern

    E-Print Network [OSTI]

    , as is the case with MRI and PET imagery. The process of automating the detection of these markers needs moreLocalization of Fiducial Skin Markers in MR Images using Correlation Pattern Recognition for PET , Roger Easton1 1 Chester F. Carlson Center for Imaging Science at the Rochester Institute of Technology

  14. INDEPENDENT COMPONENT ANALYSIS AND BEYOND IN BRAIN IMAGING: EEG, MEG, FMRI, AND PET

    E-Print Network [OSTI]

    Vialatte, François

    Technological University, Singapore ¾ Laboratory of Advanced Brain Signal Processing, Brain Science Institute applications of ICA in processing brain imaging signals: EEG, MEG, fMRI or PET. We highlight the current issuesINDEPENDENT COMPONENT ANALYSIS AND BEYOND IN BRAIN IMAGING: EEG, MEG, FMRI, AND PET Jagath C

  15. Electron cyclotron wave resonance plasma assisted deposition of cubic boron nitride thin films

    E-Print Network [OSTI]

    Zexian, Cao

    Electron cyclotron wave resonance plasma assisted deposition of cubic boron nitride thin films Z. X-pressure plasma source. The electron-cyclotron-wave resonance ECWR plasma served both to sputter the hBN target the high-resolution TEM image and the arc pattern of the 111 reflection from selected-area electron

  16. JOURNAL OF MAGNETIC RESONANCE 63, 622-628 (1985) An Efficient, Highly Hokogeneous RadiofrequencyCoil

    E-Print Network [OSTI]

    California at San Diego, University of

    1985-01-01

    that of a saddle coil or slotted tube resonator. The improved Br homogeneity is needed to generate accurateJOURNAL OF MAGNETIC RESONANCE 63, 622-628 (1985) An Efficient, Highly Hokogeneous RadiofrequencyCoil have developed radiofrequency coils for high-field head and whole-body imaging which achieve near

  17. Digital optical tomography system for dynamic breast imaging

    E-Print Network [OSTI]

    Hielscher, Andreas

    Columbia University, Department of Electrical Engineering, 1300 S.W. Mudd, 500 West 120th Street, New York, New York be used to detect tumors. We present a new digital continuous-wave optical tomography system designed imaging (MRI) has proven to be a powerful tool in monitoring high-risk women; but its high cost

  18. MILXView: A medical imaging, analysis and visualization platform.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . The aim of the Alzheimer's disease project is to develop algorithms and software to process MRI and PET in acquisition technology. However, image analysis and interpretation is still primarily performed manually with functional and molecular information from PET to allow early detection of changes related to disease

  19. Proton resonance spectroscopy

    SciTech Connect (OSTI)

    Shriner, J.F. Jr.

    1992-11-01

    Preparations for studying [sup 30]P via [sup 29]Si(p,[gamma]) have continued. We are exploring both the use of the Fourier transform and the statistical behavior of electromagnetic transition strengths within the shell model as alternate approaches to identifying quantum chaos in nuclei. Analysis of interfering resonances in (p,[alpha]) resonances suggests that improvements in the limits on detailed balance in nuclear reactions are possible, but several issues still must be considered before a definitive conclusion can be reached. Plans for a new control system for the High Resolution Laboratory's electrostatic analyzer are being implemented.

  20. Method for resonant measurement

    DOE Patents [OSTI]

    Rhodes, G.W.; Migliori, A.; Dixon, R.D.

    1996-03-05

    A method of measurement of objects to determine object flaws, Poisson`s ratio ({sigma}) and shear modulus ({mu}) is shown and described. First, the frequency for expected degenerate responses is determined for one or more input frequencies and then splitting of degenerate resonant modes are observed to identify the presence of flaws in the object. Poisson`s ratio and the shear modulus can be determined by identification of resonances dependent only on the shear modulus, and then using that shear modulus to find Poisson`s ratio using other modes dependent on both the shear modulus and Poisson`s ratio. 1 fig.

  1. Pygmy resonances and nucleosynthesis

    E-Print Network [OSTI]

    Nadia Tsoneva; Horst Lenske

    2014-11-14

    A microscopic theoretical approach based on a self-consistent density functional theory for the nuclear ground state and QRPA formalism extended with multi-phonon degrees of freedom for the nuclear excited states is implemented in investigations of new low-energy modes called pygmy resonances. Advantage of the method is the unified description of low-energy multiphonon excitations, pygmy resonances and core polarization effects. This is found of crucial importance for the understanding of the fine structure of nuclear response functions at low energies. Aspects of the precise knowledge of nuclear response functions around the neutron threshold are discussed in a connection to nucleosynthesis.

  2. Allan Cormack, Computerized Axial Tomography (CAT), and Magnetic Resonance

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnical Report: Achievements of structural genomics CitationImaging (MRI) Allan M.

  3. Resonant scattering of surface plasmon polaritons by dressed quantum dots

    SciTech Connect (OSTI)

    Huang, Danhong; Cardimona, Dave; Easter, Michelle; Gumbs, Godfrey; Maradudin, A. A.; Lin, Shawn-Yu; Zhang, Xiang

    2014-06-23

    The resonant scattering of surface plasmon-polariton waves (SPP) by embedded semiconductor quantum dots above the dielectric/metal interface is explored in the strong-coupling regime. In contrast to non-resonant scattering by a localized dielectric surface defect, a strong resonant peak in the spectrum of the scattered field is predicted that is accompanied by two side valleys. The peak height depends nonlinearly on the amplitude of SPP waves, reflecting the feedback dynamics from a photon-dressed electron-hole plasma inside the quantum dots. This unique behavior in the scattered field peak strength is correlated with the occurrence of a resonant dip in the absorption spectrum of SPP waves due to the interband photon-dressing effect. Our result on the scattering of SPP waves may be experimentally observable and applied to spatially selective illumination and imaging of individual molecules.

  4. Proton resonance spectroscopy

    SciTech Connect (OSTI)

    Shriner, J.F. Jr.

    1991-11-01

    This report discusses the following topics: Complete Level Scheme for {sup 30}P; A Search for Resonances Suitable for Tests of Detailed-Balance Violation; The Fourier Transform as a Tool for Detecting Chaos; Entrance Channel Correlations in p + {sup 27}Al; The Parity Dependence of Level Densities in {sup 49}V; and A Computer Program for the Calculation of Angular Momentum Coupling.

  5. Double resonator cantilever accelerometer

    DOE Patents [OSTI]

    Koehler, D.R.

    1982-09-23

    A digital quartz accelerometer includes a pair of spaced double-ended tuning forks fastened at one end to a base and at the other end through a spacer mass. Transverse movement of the resonator members stresses one and compresses the other, providing a differential frequency output which is indicative of acceleration.

  6. Repetitive resonant railgun power supply

    DOE Patents [OSTI]

    Honig, Emanuel M. (Los Alamos, NM); Nunnally, William C. (Los Alamos, NM)

    1988-01-01

    A repetitive resonant railgun power supply provides energy for repetitively propelling projectiles from a pair of parallel rails. The supply comprises an energy storage capacitor, a storage inductor to form a resonant circuit with the energy storage capacitor and a magnetic switch to transfer energy between the resonant circuit and the pair of parallel rails for the propelling of projectiles.

  7. Magnetic Resonance Facility (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-03-01

    This fact sheet provides information about Magnetic Resonance Facility capabilities and applications at NREL's National Bioenergy Center. Liquid and solid-state analysis capability for a variety of biomass, photovoltaic, and materials characterization applications across NREL. NREL scientists analyze solid and liquid samples on three nuclear magnetic resonance (NMR) spectrometers as well as an electron paramagnetic resonance (EPR) spectrometer.

  8. Eigenproblems in Resonant MEMS Design

    E-Print Network [OSTI]

    California at Davis, University of

    Eigenproblems in Resonant MEMS Design David Bindel UC Berkeley, CS Division Eigenproblems inResonant MEMS Design ­ p.1/21 #12;What are MEMS? Eigenproblems inResonant MEMS Design ­ p.2/21 #12;RF MEMSResonant MEMS Design ­ p.3/21 #12;Micromechanical filters Filtered signal Mechanical filter Capacitive sense

  9. Medical Imaging: ECE-4BF3 Winter 2012

    E-Print Network [OSTI]

    Haykin, Simon

    and formation; post-processing for magnetic resonance imaging and spectroscopy; comparisons to other medical with medical imaging technologies- both from a physics and engineering perspective through to a practical.). However, comparative applications with other imaging modalities (e.g. PET, SPECT, ultrasound, mammography

  10. Medical Imaging: Elec Eng -4BF3 Winter 2013

    E-Print Network [OSTI]

    Haykin, Simon

    image acquisition and formation; post-processing for magnetic resonance imaging and spectroscopy is designed to allow students to become familiar with medical imaging technologies- both from a physics modalities (e.g. PET, SPECT, ultrasound, mammography, CT, EEG, MEG) will be made where appropriate. Practical

  11. Abstract-A novel imaging method for electrical impedance tomography is implemented. In this method, the magnetic flux

    E-Print Network [OSTI]

    Eyüboðlu, Murat

    - electrical impedance tomography, magnetic resonance imaging. I. INTRODUCTION Electrical impedance tomography conductivity images [11]. Both of these techniques can be named as magnetic resonance-electrical impedanceAbstract- A novel imaging method for electrical impedance tomography is implemented. In this method

  12. Direct visualization of the perforant pathway in the human brain with ex vivo diffusion tensor imaging

    E-Print Network [OSTI]

    Augustinack, Jean

    Ex vivo magnetic resonance imaging yields high resolution images that reveal detailed cerebral anatomy and explicit cytoarchitecture in the cerebral cortex, subcortical structures, and white matter in the human brain. Our ...

  13. Nonlinear Chemical Imaging Microscopy: Near-Field Third Harmonic Generation Imaging of

    E-Print Network [OSTI]

    Cohen, Ronald C.

    radiation in human red blood cells. We show that resonantly enhanced THG is a chemically specific bulk probeNonlinear Chemical Imaging Microscopy: Near-Field Third Harmonic Generation Imaging of Human Red experiments do not produce contrast that is truly surface specific. There is much current interest in the use

  14. Line Narrowing of Fiber Coupled Laser Diode Array He Lung MRI

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    Line Narrowing of Fiber Coupled Laser Diode Array and 3 He Lung MRI by Jermane E. Massey B Coupled Laser Diode Array and 3 He Lung MRI by Jermane E. Massey Submitted to the Department of PhysicsW of injected power. A novel MRI coil and polarization system were developed for hyper-polarized 3 He lung

  15. BRIEF COMMUNICATION A 7 Tesla fMRI Study of Amygdala Responses to Fearful Faces

    E-Print Network [OSTI]

    Hadjikhani, Nouchine

    BRIEF COMMUNICATION A 7 Tesla fMRI Study of Amygdala Responses to Fearful Faces Wietske van der field strength. In this study, the feasibility of fMRI in the amygdalae at 7 Tesla was investigated in a fearful face depends on stimulus duration. Keywords Amygdala Á fMRI Á 7 Tesla Á Fear Á Face perception

  16. Assessing Visuospatial Neglect in Children with Brain Injury 

    E-Print Network [OSTI]

    Wahlberg, Andrea Christine

    2014-05-28

    lead to overgeneralization of the neural basis of VSN (Ting et al., 2011). Brain imaging studies utilizing functional magnetic resonance imaging (fMRI), positron emission tomography (PET), perfusion weighted imaging (PWI), and diffusion 15...

  17. Donna Rose Addis, TWRI, May 2004 1 ANALYSIS OF FUNCTIONAL MAGNETIC RESONANCE

    E-Print Network [OSTI]

    Addis, Donna Rose

    Donna Rose Addis, TWRI, May 2004 1 ANALYSIS OF FUNCTIONAL MAGNETIC RESONANCE IMAGING DATA USING SPM-ordinates (with signs reversed) into table as translations right, fwd and up · Check origin is at the AC · Select images (a_seg1.img, a_seg2 and brain_a.img) · Name output file (grey_clean) · Enter formula

  18. Morphology of the Small-Animal Lung Using Magnetic Resonance Microscopy

    E-Print Network [OSTI]

    Morphology of the Small-Animal Lung Using Magnetic Resonance Microscopy Laurence W. Hedlund and G motion control and animal support, the lungs of the live, small animal can be imaged. Although in vivo He, it is possible to image the tissue and gas compartments of the lung. This capability

  19. IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 27, NO. 8, AUGUST 2008 1095 Automatic Detection of Regional Heart Rejection

    E-Print Network [OSTI]

    Moura, José

    of Regional Heart Rejection in USPIO-Enhanced MRI Hsun-Hsien Chang, Member, IEEE, José M. F. Moura*, Fellow. When a transplanted heart undergoes rejection, immune cells will infiltrate the allograft. Imaged by 2 in the image facilitates the identifi- cation of acute heart rejection. This paper develops a classifier

  20. Reciprocity and gyrotropism in magnetic resonance transduction

    SciTech Connect (OSTI)

    Tropp, James

    2006-12-15

    We give formulas for transduction in magnetic resonance - i.e., the appearance of an emf due to Larmor precession of spins - based upon the modified Lorentz reciprocity principle for gyrotropic (also called 'nonreciprocal') media, i.e., in which a susceptibility tensor is carried to its transpose by reversal of an external static field [cf., R. F. Harrington and A. T. Villeneuve IRE Trans. Microwave Theory and Technique MTT6, 308 (1958)]. Prior applications of reciprocity to magnetic resonance, despite much success, have ignored the gyrotropism which necessarily arises due to nuclear and/or unpaired electronic spins. For detection with linearly polarized fields, oscillating at the Larmor frequency, the emf is written in terms of a volume integral containing a product of two factors which we define as the antenna patterns, i.e. (H{sub 1x}{+-}iH{sub 1y}), where, e.g., for a single transceive antenna, the H's are just the spatially dependent oscillatory magnetic field strengths, per the application of some reference current at the antenna terminals, with the negative sign obtaining for transmission, and the positive for reception. Similar expressions hold for separate transmit and receive antennas; expressions are also given for circular polarization of the fields. We then exhibit a receive-only array antenna of two elements for magnetic resonance imaging of protons, which, due an intensity artifact arising from stray reactive coupling of the elements, produces, despite its own bilateral symmetry, asymmetric proton NMR images of a symmetric cylindrical phantom containing aqueous saline solution [J. Tropp and T. Schirmer, J. Magn. Reson. 151, 146 (2001)]. Modification of this two-port antenna, to function in transmit-receive mode, allows us to demonstrate highly nonreciprocal behavior: that is, to record images (of cylindrical test phantoms containing aqueous saline solution) whose appearance dramatically changes, when the roles of transmission and reception are swapped between the two antenna ports--giving in one instance a signal intensity pattern whose form resembles an umbrella (i.e., with a central column of moderate intensity surmounted by a bright canopy), and in the other, a distorted oval with slight concavities at its horizontal extremes, whose outline suggests that of a cat's eye. The relation between image patterns and drive scheme can be shown to reverse if the static polarizing field is reversed. Electromagnetic and circuit calculations, together with the modified reciprocity principle, allow us to reproduce these pattern changes in numerical simulations, closely and convincingly. Although the imaging experiments are performed at a static field of 3.0 T, and consequently a Larmor frequency of 128 MHz, the nonreciprocal effects are not related to the shortness of the wavelength in aqueous medium, but appear equally in simulations based in either the quasistatic or full electromagnetic regimes. Finally, we show that although antenna patterns for transmission and reception are swapped with reversal of the polarizing field, meaning that the receive pattern equals the transmit pattern with the field reversed, this in no way invalidates the familiar rotating wave model of spin dynamics in magnetic resonance.

  1. Test Images

    E-Print Network [OSTI]

    Test Images. I hope to have a set of test images for the course soon. Some images are available now; some will have to wait until I can find another 100-200

  2. Geometry-Invariant Resonant Cavities

    E-Print Network [OSTI]

    Liberal, Iñigo; Engheta, Nader

    2015-01-01

    Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modeling to everyday life devices. The eigenfrequencies of conventional cavities are a function of its geometry, and, thus, the size and shape of a resonant cavity is selected in order to operate at a specific frequency. Here, we demonstrate theoretically the existence of geometry-invariant resonant cavities, i.e., resonators whose eigenfrequency is invariant with respect to geometrical deformations. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, which enable decoupling of the time and spatial field variations. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices.

  3. Nanotube resonator devices

    DOE Patents [OSTI]

    Jensen, Kenneth J; Zettl, Alexander K; Weldon, Jeffrey A

    2014-05-06

    A fully-functional radio receiver fabricated from a single nanotube is being disclosed. Simultaneously, a single nanotube can perform the functions of all major components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A DC voltage source, as supplied by a battery, can power the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, successful music and voice reception has been demonstrated. Also disclosed are a radio transmitter and a mass sensor using a nanotube resonator device.

  4. Proton capture resonance studies

    SciTech Connect (OSTI)

    Mitchell, G.E. [North Carolina State University, Raleigh, North Carolina (United States) 27695]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Bilpuch, E.G. [Duke University, Durham, North Carolina (United States) 27708]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Bybee, C.R. [North Carolina State University, Raleigh, North Carolina (United States) 27695]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Cox, J.M.; Fittje, L.M. [Tennessee Technological University, Cookeville, Tennessee (United States) 38505]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Labonte, M.A.; Moore, E.F.; Shriner, J.D. [North Carolina State University, Raleigh, North Carolina (United States) 27695]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Shriner, J.F. Jr. [Tennessee Technological University, Cookeville, Tennessee (United States) 38505]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Vavrina, G.A. [North Carolina State University, Raleigh, North Carolina (United States) 27695]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708; Wallace, P.M. [Duke University, Durham, North Carolina (United States) 27708]|[Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States) 27708

    1997-02-01

    The fluctuation properties of quantum systems now are used as a signature of quantum chaos. The analyses require data of extremely high quality. The {sup 29}Si(p,{gamma}) reaction is being used to establish a complete level scheme of {sup 30}P to study chaos and isospin breaking in this nuclide. Determination of the angular momentum J, the parity {pi}, and the isospin T from resonance capture data is considered. Special emphasis is placed on the capture angular distributions and on a geometric description of these angular distributions. {copyright} {ital 1997 American Institute of Physics.}

  5. Resonance test system

    DOE Patents [OSTI]

    Musial, Walter (Boulder, CO); White, Darris (Superior, CO)

    2011-05-31

    An apparatus (10) for applying at least one load to a specimen (12) according to one embodiment of the invention may comprise a mass (18). An actuator (20) mounted to the specimen (12) and operatively associated with the mass (18) moves the mass (18) along a linear displacement path (22) that is perpendicular to a longitudinal axis of the specimen (12). A control system (26) operatively associated with the actuator (20) operates the actuator (20) to reciprocate the mass (18) along the linear displacement path (22) at a reciprocating frequency, the reciprocating frequency being about equal to a resonance frequency of the specimen (12) in a test configuration.

  6. Regarding Confinement Resonances

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100 Winners * ImpactsandRegarding Confinement Resonances Print When an atom is

  7. Regarding Confinement Resonances

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100 Winners * ImpactsandRegarding Confinement Resonances Print When an atom

  8. Analysis of Functional MRI Timeseries Data Using Signal Processing Techniques

    E-Print Network [OSTI]

    /39 #12;fMRI: The basic idea Experimental paradigm designed to activate neuronal metabolism Changes conjugate gradient Regularization parameter A found by crossvalidation strategy S. Chen ­ Final Exam optimization with conjugate gradient 0.5 s time resolution estimate from TR = 0.5 s dataset Supertemporal

  9. Temporal Regularization Use in Dynamic Contrast-Enhanced MRI

    E-Print Network [OSTI]

    Fessler, Jeffrey A.

    ;ACKNOWLEDGEMENTS I am incredibly grateful to so many people for all of the love, support, and guidance I have's endless guidance, patience, and support. Thank you. I also want to thank the other members of my committee: Doug Noll, who first taught me the nuts and bolts of MRI, and whose group meetings and group members

  10. Image Fusion for MR Bias Stochastic Systems Group

    E-Print Network [OSTI]

    Willsky, Alan S.

    We can target T1 and T2 through appropriate selection of TE and TR. #12;Image Reconstruction The MRImage Fusion for MR Bias Correction Ayres Fan Stochastic Systems Group Joint work with W. Wells, J. Fisher, M. Cetin, S. Haker, A. Willsky, B. Mulkern #12;Magnetic Resonance The magnetic resonance (MR

  11. Electromagnetic production of hyperon resonances

    E-Print Network [OSTI]

    K. Hicks; D. Keller; W. Tang

    2010-12-14

    The study of hyperon resonances has entered a new era of precision with advent of high-statistics photoproduction data from the CLAS detector at Jefferson Lab. These data have multi-particle final states, allowing clean identification of exclusive reactions associated with strange mesons and baryons. Examples of physics results are: evidence for isospin interference in the decay of the $\\Lambda(1405)$ resonance; a strong suggestion of meson cloud effects in the structure of the $\\Sigma(1385)$ resonance; data from $K^*$ photoproduction that will test the existence of the purported $K_0(800)$ meson. Properties of other hyperon resonances will also be studied in the near future.

  12. Does Geometric Coupling Generates Resonances?

    E-Print Network [OSTI]

    I. C. Jardim; G. Alencar; R. R. Landim; R. N. Costa Filho

    2015-05-08

    Geometrical coupling in a co-dimensional one Randall-Sundrum scenario (RS) is used to study resonances of $p-$form fields. The resonances are calculated using the transfer matrix method. The model studied consider the standard RS with delta-like branes, and branes generated by kinks and domain-wall as well. The parameters are changed to control the thickness of the smooth brane. With this a very interesting pattern is found for the resonances. The geometrical coupling does not generate resonances for the reduced $p-$form in all cases considered.

  13. MEMS Resonant Strain Sensor Integration

    E-Print Network [OSTI]

    Myers, David Richard

    2010-01-01

    Strap-down microelectromechanical MEMS sensors for high-gdate of microelectromechanical systems (MEMS) is a bitmicroelectromechanical resonant output gyroscope. MEMS 2002,

  14. Subsynchronous resonance in power systems

    SciTech Connect (OSTI)

    Anderson, P.M. (Power Math Associates, Inc. (US)); Agrawal, B.L. (Arizona Public Service Co., Phoenix, AZ (United States)); Van Ness, J.E. (Northwestern Univ., Evanston, IL (United States). Dept. of Electrical Engineering and Computer Science)

    1990-01-01

    This book provides an introduction to subsynchronous resonance in power systems and includes material on system modeling, system parameters, and system analysis.

  15. Cyclotron subharmonics resonant (CSR) heating

    SciTech Connect (OSTI)

    Abe, H.

    1994-01-01

    The cyclotron subharmonics resonant (CSR) heating mechanism is studied using particle simulation codes with an emphasis on the relationship between CSR and the nonlinear Landua damping.

  16. Medical Imaging: ECE-4BF3 Michael D. Noseworthy, Ph.D., P.Eng.

    E-Print Network [OSTI]

    Haykin, Simon

    ; post-processing for magnetic resonance imaging and spectroscopy; comparisons to other medical imaging This course is designed to allow students to become familiar with medical imaging technologies- both from imaging modalities (e.g. PET, SPECT, ultrasound, mammography, CT, EEG, MEG) will be made where appropriate

  17. Towards Systematic Exploration of Tradeoffs for Medical Image Registration on Heterogeneous Platforms

    E-Print Network [OSTI]

    Bhattacharyya, Shuvra S.

    . INTRODUCTION Advances in medical imaging technologies have enabled medical diagnoses and procedures simply of imaging modalities (e.g. computed tomography (CT), positron emission tomography (PET), magnetic resonance into one integrated view through a procedure called image registration. Image registration is the process

  18. DownloadedAt:19:2615October2007 Computer Aided Surgery, January 2007; 12(1): 214

    E-Print Network [OSTI]

    Camesano, Terri

    ]. Advances in magnet design and magnetic resonance (MR) system technology, coupled with the development MRI image overlay: Application to arthrography needle insertion GREGORY S. FISCHER1 , ANTON DEGUET1, Maryland, USA (Received 30 May 2006; accepted 14 August 2006) Abstract Magnetic Resonance Imaging (MRI

  19. Prosper: image and robot-guided prostate brachytherapy

    E-Print Network [OSTI]

    Baumann, Michael; Daanen, Vincent; Descotes, Jean-Luc; Giraud, Jean-Yves; Hungr, Nikolai; Leroy, Antoine; Long, Jean-Alexandre; Martin, Sébastien; Troccaz, Jocelyne

    2011-01-01

    Brachytherapy for localized prostate cancer consists in destroying cancer by introducing iodine radioactive seeds into the gland through hollow needles. The planning of the position of the seeds and their introduction into the prostate is based on intra-operative ultrasound (US) imaging. We propose to optimize the global quality of the procedure by: i) using 3D US; ii) enhancing US data with MRI registration; iii) using a specially designed needle-insertion robot, connected to the imaging data. The imaging methods have been successfully tested on patient data while the robot accuracy has been evaluated on a realistic deformable phantom.

  20. Basics of Resonance Chiral Theory

    E-Print Network [OSTI]

    J. Portoles

    2010-10-16

    We review the main components that have to be considered, within Resonance Chiral Theory, in the study of processes whose dynamics is dominated by hadron resonances. We show its application in the study of the tau -> (3 pion) nu_tau decay.

  1. Giant resonances in Mg-24 

    E-Print Network [OSTI]

    Youngblood, David H.; Lui, YW; Clark, HL.

    1999-01-01

    The giant resonance region in Mg-24 was studied with inelastic scattering of 240 MeV alpha particles at small angles including 0 degrees. The giant resonance peak was found to extend up to E-X = 41 MeV. Isoscalar E0, E1, and E2 strength...

  2. Delta connected resonant snubber circuit

    DOE Patents [OSTI]

    Lai, J.S.; Peng, F.Z.; Young, R.W. Sr.; Ott, G.W. Jr.

    1998-01-20

    A delta connected, resonant snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the dc supply voltage through the main inverter switches and the auxiliary switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter. 36 figs.

  3. Delta connected resonant snubber circuit

    DOE Patents [OSTI]

    Lai, Jih-Sheng (Knoxville, TN); Peng, Fang Zheng (Oak Ridge, TN); Young, Sr., Robert W. (Oak Ridge, TN); Ott, Jr., George W. (Knoxville, TN)

    1998-01-01

    A delta connected, resonant snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the dc supply voltage through the main inverter switches and the auxiliary switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  4. Baryon Spectroscopy and Resonances

    SciTech Connect (OSTI)

    Robert Edwards

    2011-12-01

    A short review of current efforts to determine the highly excited state spectrum of QCD, and in particular baryons, using lattice QCD techniques is presented. The determination of the highly excited spectrum of QCD is a major theoretical and experimental challenge. The experimental investigation of the excited baryon spectrum has been a long-standing element of the hadronic-physics program, an important component of which is the search for so-called 'missing resonances', baryonic states predicted by the quark model based on three constituent quarks but which have not yet been observed experimentally. Should such states not be found, it may indicate that the baryon spectrum can be modeled with fewer effective degrees of freedom, such as in quark-diquark models. In the past decade, there has been an extensive program to collect data on electromagnetic production of one and two mesons at Jefferson Lab, MIT-Bates, LEGS, MAMI, ELSA, and GRAAL. To analyze these data, and thereby refine our knowledge of the baryon spectrum, a variety of physics analysis models have been developed at Bonn, George Washington University, Jefferson Laboratory and Mainz. To provide a theoretical determination and interpretation of the spectrum, ab initio computations within lattice QCD have been used. Historically, the calculation of the masses of the lowest-lying states, for both baryons and mesons, has been a benchmark calculation of this discretized, finite-volume computational approach, where the aim is well-understood control over the various systematic errors that enter into a calculation; for a recent review. However, there is now increasing effort aimed at calculating the excited states of the theory, with several groups presenting investigations of the low-lying excited baryon spectrum, using a variety of discretizations, numbers of quark flavors, interpolating operators, and fitting methodologies. Some aspects of these calculations remain unresolved and are the subject of intense effort, notably the ordering of the Roper resonance in the low-lying Nucleon spectrum.

  5. Auxiliary resonant DC tank converter

    DOE Patents [OSTI]

    Peng, Fang Z. (Knoxville, TN)

    2000-01-01

    An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

  6. Calibration of fluorescence resonance energy transfer in microscopy

    DOE Patents [OSTI]

    Youvan, Dougalas C.; Silva, Christopher M.; Bylina, Edward J.; Coleman, William J.; Dilworth, Michael R.; Yang, Mary M.

    2003-12-09

    Imaging hardware, software, calibrants, and methods are provided to visualize and quantitate the amount of Fluorescence Resonance Energy Transfer (FRET) occurring between donor and acceptor molecules in epifluorescence microscopy. The MicroFRET system compensates for overlap among donor, acceptor, and FRET spectra using well characterized fluorescent beads as standards in conjunction with radiometrically calibrated image processing techniques. The MicroFRET system also provides precisely machined epifluorescence cubes to maintain proper image registration as the sample is illuminated at the donor and acceptor excitation wavelengths. Algorithms are described that pseudocolor the image to display pixels exhibiting radiometrically-corrected fluorescence emission from the donor (blue), the acceptor (green) and FRET (red). The method is demonstrated on samples exhibiting FRET between genetically engineered derivatives of the Green Fluorescent Protein (GFP) bound to the surface of Ni chelating beads by histidine-tags.

  7. Calibration of fluorescence resonance energy transfer in microscopy

    DOE Patents [OSTI]

    Youvan, Douglas C. (San Jose, CA); Silva, Christopher M. (Sunnyvale, CA); Bylina, Edward J. (San Jose, CA); Coleman, William J. (Moutain View, CA); Dilworth, Michael R. (Santa Cruz, CA); Yang, Mary M. (San Jose, CA)

    2002-09-24

    Imaging hardware, software, calibrants, and methods are provided to visualize and quantitate the amount of Fluorescence Resonance Energy Transfer (FRET) occurring between donor and acceptor molecules in epifluorescence microscopy. The MicroFRET system compensates for overlap among donor, acceptor, and FRET spectra using well characterized fluorescent beads as standards in conjunction with radiometrically calibrated image processing techniques. The MicroFRET system also provides precisely machined epifluorescence cubes to maintain proper image registration as the sample is illuminated at the donor and acceptor excitation wavelengths. Algorithms are described that pseudocolor the image to display pixels exhibiting radiometrically-corrected fluorescence emission from the donor (blue), the acceptor (green) and FRET (red). The method is demonstrated on samples exhibiting FRET between genetically engineered derivatives of the Green Fluorescent Protein (GFP) bound to the surface of Ni chelating beads by histidine-tags.

  8. Combined MRI and Fluoroscopic Guided Radiofrequency Ablation of a Renal Tumor

    SciTech Connect (OSTI)

    Fotiadis, Nikolas I., E-mail: fotiadis.nicholas@gmail.co [Royal London Hospital, Department of Interventional Radiology (United Kingdom); Sabharwal, Tarun [Guy's and St Thomas' Hospital, Interventional Radiology Department (United Kingdom); Gangi, Afshin [University Hospital of Strasbourg, Radiology Department (France); Adam, Andreas [Guy's and St Thomas' Hospital, Interventional Radiology Department (United Kingdom)

    2009-01-15

    Percutaneous CT- and ultrasound-guided radiofrequency ablation of renal cell carcinoma (RCC) has been shown to have very promising medium-term results. We present a unique case of recurrent RCC after partial nephrectomy in a patient with a single kidney and impaired renal function. This tumor could not be visualized either with CT or with ultrasound. A combination of magnetic resonance imaging and fluoroscopic guidance was used, to the best of our knowledge for the first time, to ablate the tumor with radiofrequency. The patient was cancer-free and off dialysis at 30-month follow up.

  9. Nuclear Resonance Fluorescence for Materials Assay

    E-Print Network [OSTI]

    Quiter, Brian

    2010-01-01

    clandestine material with nuclear resonance fluorescence”.E. Norman, UC Berkeley Dept. of Nuclear Engineering, privatepp. 349. G. Warren et al. “Nuclear Resonance Fluorescence of

  10. Nuclear Resonance Fluorescence for Materials Assay

    E-Print Network [OSTI]

    Quiter, Brian J.

    2010-01-01

    et al. “Investigation of Nuclear Structure by Resonance1996, pp. G. Warren et al. “Nuclear Resonance Fluorescenceof 235U” IEEE Nuclear Science Symposium 2006, pp. 914. W.

  11. Tunable and angle-insensitive plasmon resonances in graphene ribbon arrays with multispectral diffraction response

    SciTech Connect (OSTI)

    Li, Kangwen; Ma, Xunpeng; Zhang, Zuyin; Xu, Yun, E-mail: xuyun@semi.ac.cn; Song, Guofeng [Institute of Semiconductors, Chinese Academy of Sciences, Beijing (China)

    2014-03-14

    Plasmon resonances in graphene ribbon arrays are investigated numerically by means of the Finite Element Method. Numerical analysis shows that a series of multipolar resonances take place when graphene ribbon arrays are illuminated by a TM polarized electromagnetic wave. Moreover, these resonances are angle-independent, and can be tuned greatly by the width and the doping level of the graphene ribbons. Specifically, we demonstrate that for graphene arrays with several sets of graphene ribbons, which have different widths or doping levels, each of these multipolar resonances will be split into several ones. In addition, as plasmon resonances can confine electromagnetic field at the ribbon edges, graphene ribbons with different widths or doping levels offer intriguing application for electrically tunable spectral imaging.

  12. Multiple resonant railgun power supply

    DOE Patents [OSTI]

    Honig, Emanuel M. (Los Alamos, NM); Nunnally, William C. (Los Alamos, NM)

    1988-01-01

    A multiple repetitive resonant railgun power supply provides energy for repetitively propelling projectiles from a pair of parallel rails. A plurality of serially connected paired parallel rails are powered by similar power supplies. Each supply comprises an energy storage capacitor, a storage inductor to form a resonant circuit with the energy storage capacitor and a magnetic switch to transfer energy between the resonant circuit and the pair of parallel rails for the propelling of projectiles. The multiple serial operation permits relatively small energy components to deliver overall relatively large amounts of energy to the projectiles being propelled.

  13. SHARE: Statistical Hadronization with Resonances

    E-Print Network [OSTI]

    Giorgio Torrieri; Steve Steinke; Wojciech Broniowski; Wojciech Florkowski; Jean Letessier; Johann Rafelski

    2004-07-22

    SHARE is a collection of programs designed for the statistical analysis of particle production in relativistic heavy-ion collisions. With the physical input of intensive statistical parameters, it generates the ratios of particle abundances. The program includes cascade decays of all confirmed resonances from the Particle Data Tables. The complete treatment of these resonances has been known to be a crucial factor behind the success of the statistical approach. An optional feature implemented is a Breit--Wigner type distribution for strong resonances. An interface for fitting the parameters of the model to the experimental data is provided.

  14. Image alignment

    DOE Patents [OSTI]

    Dowell, Larry Jonathan

    2014-04-22

    Disclosed is a method and device for aligning at least two digital images. An embodiment may use frequency-domain transforms of small tiles created from each image to identify substantially similar, "distinguishing" features within each of the images, and then align the images together based on the location of the distinguishing features. To accomplish this, an embodiment may create equal sized tile sub-images for each image. A "key" for each tile may be created by performing a frequency-domain transform calculation on each tile. A information-distance difference between each possible pair of tiles on each image may be calculated to identify distinguishing features. From analysis of the information-distance differences of the pairs of tiles, a subset of tiles with high discrimination metrics in relation to other tiles may be located for each image. The subset of distinguishing tiles for each image may then be compared to locate tiles with substantially similar keys and/or information-distance metrics to other tiles of other images. Once similar tiles are located for each image, the images may be aligned in relation to the identified similar tiles.

  15. Distribution of neutron resonance widths

    E-Print Network [OSTI]

    Hans A. Weidenmueller

    2011-10-28

    Recent data on neutron resonance widths indicate disagreement with the Porter-Thomas distribution (PTD). I discuss the theoretical arguments for the PTD, possible theoretical modifications, and I summarize the experimantal evidence.

  16. Resonance Expansions and Rayleigh Waves

    E-Print Network [OSTI]

    We consider the general framework of the “black box scattering” introduced ... for the first time an expansion of the type (1) for trapping systems (having “almost real” resonances) in the black box ...... M. Zworski, private communication, 1992. 14.

  17. Nuclear magnetic resonance readable sensors

    E-Print Network [OSTI]

    Ling, Yibo

    2010-01-01

    The monitoring of physiological biomarkers is fundamental to the diagnosis and treatment of disease. We describe here the development of molecular sensors which can be read by magnetic resonance (MR) relaxometry. MR is an ...

  18. Nested Trampoline Resonators for Optomechanics

    E-Print Network [OSTI]

    Weaver, Matthew J; Luna, Fernando; Buters, Frank M; Eerkens, Hedwig J; Welker, Gesa; Perock, Blaise; Heeck, Kier; de Man, Sven; Bouwmeester, Dirk

    2015-01-01

    Two major challenges in the development of optomechanical devices are achieving a low mechanical and optical loss rate and vibration isolation from the environment. We address both issues by fabricating novel trampoline resonators made from low pressure chemical vapor deposition (LPCVD) Si$_3$N$_4$ with a distributed bragg reflector (DBR) mirror. We construct a nested double resonator structure that generates approximately 80 dB of mechanical isolation from the mounting surface, eliminating the strong mounting dependence of the quality factor observed with single resonators. With the consistency provided by this isolation scheme we reliably fabricate devices with mechanical quality factors of around 400,000 at room temperature. In addition these devices were used to form optical cavities with finesse up to 181,000 $\\pm$ 1,000. These promising parameters will enable experiments in the quantum regime with macroscopic mechanical resonators.

  19. Baryon Resonances Observed at BES

    E-Print Network [OSTI]

    B. S. Zou

    2008-02-01

    The $\\psi$ decays provide a novel way to explore baryon spectroscopy and baryon structure. The baryon resonances observed from $\\psi$ decays at BES are reviewed. The implications and prospects at upgraded BESIII/BEPCII are discussed.

  20. Informatics methods to enable sharing of quantitative imaging research data,

    E-Print Network [OSTI]

    Rubin, Daniel L.

    reuse of quantitative imaging data in the community. Methods: We performed a survey of the current tools online at www.sciencedirect.com Magnetic Resonance Imaging 30 (2012) 1249­1256 Disclosures of conflict of interest: Mia Levy, none; John Freymann, none; Justin Kirby, none; Andriy Fedorov, Ph.D., none; Fiona

  1. Micro-machined resonator oscillator

    DOE Patents [OSTI]

    Koehler, D.R.; Sniegowski, J.J.; Bivens, H.M.; Wessendorf, K.O.

    1994-08-16

    A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a telemetered sensor beacon'' that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20--100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available. 21 figs.

  2. Micro-machined resonator oscillator

    DOE Patents [OSTI]

    Koehler, Dale R. (Albuquerque, NM); Sniegowski, Jeffry J. (Albuquerque, NM); Bivens, Hugh M. (Albuquerque, NM); Wessendorf, Kurt O. (Albuquerque, NM)

    1994-01-01

    A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available.

  3. Modelado del Efecto de Volumen Parcial en MRI Cardiacas mediante Mezclas de Gaussianas

    E-Print Network [OSTI]

    estimaci´on del PVE sobre MRI card´iaca, de- be entenderse asociado a la estrategia de modelado que se

  4. SQUID-Detected MRI in the Limit of Zero Static Field

    E-Print Network [OSTI]

    Kelso, Nathan

    2009-01-01

    for MRI in zero static field. . . . . . . . . . . . . . .acquired in the zero-static-field limit . . . . . 6.3.2versus power dissipated in a static field . . . . . . 7.4

  5. Microfluidically Cryo-Cooled Planar Coils for Magnetic Resonance Imaging 

    E-Print Network [OSTI]

    Koo, Chiwan

    2013-08-09

    -cooling microfluidic channel layer (d-f), and the final assembly and tubing insertion (g). (a) Negative photoresist (NR2-20000P) patterning on a thin PMMA substrate with Cr/Cu as seed layers. (b) Cu electroplating to 25 ?m height and removal of the photoresist... and Cr/Cu seed layers. (c) Thin PDMS coating. (d) SU-8 mold fabrication on Si substrate. (e) PDMS casting on the master mold for liquid nitrogen channel layer fabrication. (f) PDMS channel layer releasing and hole punching for tubing insertion. (g...

  6. On the dynamics of magnetic fluids in magnetic resonance imaging

    E-Print Network [OSTI]

    Cantillon-Murphy, Pádraig J

    2008-01-01

    The hydrodynamics of magnetic fluids, often termed ferrofluids, has been an active area of research since the mid 1960s. However, it is only in the past twenty years that these fluids have begun to be used in magnetic ...

  7. Adaptive alternating minimization for fitting magnetic resonance spectroscopic imaging

    E-Print Network [OSTI]

    constraints and to use good starting values in the nonconvex metabolite quantification optimization problems. In partic- ular, we focus on the spatial smoothness of the nonlinear model parameters across the MRSI grid

  8. SQUID-Detected Magnetic Resonance Imaging in Microtesla Fields

    E-Print Network [OSTI]

    Moessle, Michael; Hatridge, Michael; Clarke, John

    2008-01-01

    System for prostate brachytherapy and biopsy in a standardprostate tumors (brachytherapy) (54). Cryosurgery involves

  9. Bayesian Experimental Design of Magnetic Resonance Imaging Sequences

    E-Print Network [OSTI]

    Seeger, Matthias

    Nickisch, Rolf Pohmann and Bernhard Sch¨olkopf Max Planck Institute for Biological Cybernetics research of the brain. Without applying any harmful ioniz- ing radiation, this technique stands out by its

  10. Genetically encoded reporters for hyperpolarized xenon magnetic resonance imaging

    E-Print Network [OSTI]

    experiments performed on living cells. G enetically encoded optical reporters, such as the green fluor- escent

  11. Bioengineering/Radiology 278: Magnetic Resonance Imaging Laboratory Winter 2011

    E-Print Network [OSTI]

    California at San Diego, University of

    Design and implement a 2D RF pulse 7 RF coil design Quadrature Detection Classes of coils Design criteria

  12. Measurement of brain temperature using magnetic resonance spectroscopic imaging 

    E-Print Network [OSTI]

    Parikh, Jehill

    2013-07-06

    The study of brain temperature is important for a number of clinical conditions such as stroke, traumatic brain injury, schizophrenia and birth asphyxia (for neonates). A direct method to estimate brain temperature ...

  13. Microelectromechanical resonator and method for fabrication

    SciTech Connect (OSTI)

    Wittwer, Jonathan W. (Albuquerque, NM); Olsson, Roy H. (Albuquerque, NM)

    2009-11-10

    A method is disclosed for the robust fabrication of a microelectromechanical (MEM) resonator. In this method, a pattern of holes is formed in the resonator mass with the position, size and number of holes in the pattern being optimized to minimize an uncertainty .DELTA.f in the resonant frequency f.sub.0 of the MEM resonator due to manufacturing process variations (e.g. edge bias). A number of different types of MEM resonators are disclosed which can be formed using this method, including capacitively transduced Lame, wineglass and extensional resonators, and piezoelectric length-extensional resonators.

  14. Microelectromechanical resonator and method for fabrication

    SciTech Connect (OSTI)

    Wittwer, Jonathan W. (Albuquerque, NM); Olsson, Roy H. (Albuquerque, NM)

    2010-01-26

    A method is disclosed for the robust fabrication of a microelectromechanical (MEM) resonator. In this method, a pattern of holes is formed in the resonator mass with the position, size and number of holes in the pattern being optimized to minimize an uncertainty .DELTA.f in the resonant frequency f.sub.0 of the MEM resonator due to manufacturing process variations (e.g. edge bias). A number of different types of MEM resonators are disclosed which can be formed using this method, including capacitively transduced Lame, wineglass and extensional resonators, and piezoelectric length-extensional resonators.

  15. Precedence of the Eye Region in Neural Processing of Faces

    E-Print Network [OSTI]

    Issa, Elias

    Functional magnetic resonance imaging (fMRI) has revealed multiple subregions in monkey inferior temporal cortex (IT) that are selective for images of faces over other objects. The earliest of these subregions, the posterior ...

  16. Affect Regulation Modulates Brain Response to Food Pictures in Obese Participants

    E-Print Network [OSTI]

    Patrician, Trisha M.

    2011-04-08

    The present study uses functional magnetic resonance imaging (fMRI) to investigate whether differences in self-reported emotion regulatory ability are associated with differential patterns of responding to food images. ...

  17. Effects of Surgical Repair or Reconstruction on Radiocarpal Mechanics from Wrists with Scapholunate Ligament Injury

    E-Print Network [OSTI]

    Johnson, Joshua

    2013-05-31

    ) and finite element modeling (FEM). The modeling process required geometries, boundary conditions and a contact relationship. Magnetic resonance imaging (MRI) was used to acquire images of the normal, injured and post-operative wrists, while relaxed and during...

  18. Stochastic Resonance: from climate to biology

    E-Print Network [OSTI]

    Roberto Benzi

    2007-02-05

    In this paper I will review some basic aspects of the mechanism of stochastic resonance. Stochastic resonance was first introduced as a possible mechanism to explain long term climatic variation. Since then, there have been many applications of stochastic resonance in physical and biological systems. I will show that in complex system, stochastic resonance can substantially change as a function of the ``system complexity''. Also, I will briefly mention how to apply stochastic resonance for the case of Brownian motors.

  19. IEEE/ASME TRANSACTIONS ON MECHATRONICS, VOL. 13, NO. 3, JUNE 2008 265 Guest Editorial

    E-Print Network [OSTI]

    Mavroidis, Constantinos

    IEEE/ASME TRANSACTIONS ON MECHATRONICS, VOL. 13, NO. 3, JUNE 2008 265 Guest Editorial Introduction to the Focused Section on Mechatronic Systems for MRI Applications MAGNETIC resonance imaging (MRI of robotic and mechatronic systems in MRI lies in their ability to precisely quantify and remotely control

  20. 2015 TRANS-INSTITUTIONAL PROGRAM AWARD RECIPIENTS

    E-Print Network [OSTI]

    in the application of magnetic resonance imaging (MRI) to the neurosciences. The 7 Tesla human MRI instrument was one the next generation of high-field MRI instruments that will provide broader field of coverage and higher resolution. The goal is to increase the number of transmitters and channels on the 7 Tesla instrument from

  1. Ultra-low field nuclear magnetic resonance and magnetic resonance imaging to discriminate and identify materials

    DOE Patents [OSTI]

    Matlashov, Andrei Nikolaevich; Urbaitis, Algis V.; Savukov, Igor Mykhaylovich; Espy, Michelle A.; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry

    2013-03-05

    Method comprising obtaining an NMR measurement from a sample wherein an ultra-low field NMR system probes the sample and produces the NMR measurement and wherein a sampling temperature, prepolarizing field, and measurement field are known; detecting the NMR measurement by means of inductive coils; analyzing the NMR measurement to obtain at least one measurement feature wherein the measurement feature comprises T1, T2, T1.rho., or the frequency dependence thereof; and, searching for the at least one measurement feature within a database comprising NMR reference data for at least one material to determine if the sample comprises a material of interest.

  2. Unified algebraic treatment of resonance

    E-Print Network [OSTI]

    A. D. Alhaidari

    2004-05-05

    Energy resonance in scattering is usually investigated either directly in the complex energy plane (E-plane) or indirectly in the complex angular momentum plane (L-plane). Another formulation complementing these two approaches was introduced recently. It is an indirect algebraic method that studies resonances in a complex charge plane (Z-plane). This latter approach will be generalized to provide a unified algebraic treatment of resonances in the complex E-, L-, and Z-planes. The complex scaling (rotation) method will be used in the development of this approach. The resolvent operators (Green's functions) are formally defined in these three spaces. Bound states spectrum and resonance energies in the E-plane are mapped onto a discrete set of poles of the respective resolvent operator on the real line of the L- and Z-planes. These poles move along trajectories as the energy is varied. A finite square integrable basis is used in the numerical implementation of this approach. Stability of poles and trajectories against variation in all computational parameters is demonstrated. Resonance energies for a given potential are calculated and compared with those obtained by other studies.

  3. Support system design for a superconducting MRI magnet 

    E-Print Network [OSTI]

    Watts, Louis Chad

    1993-01-01

    . A design of a support system for a superconducting magnet was developed. This system will be used to suspend the Texas Accelerator Center (TAC) liquid helium cooled, four tesla, one meter bore, superconducting coils (cold mass) inside a room...-to-noise ratio is approximately proportional to the magnetic field'. TAC's magnet has a 4 tesla (T) field slrength for improved resolution compared to commercially available MRI magnets at 0. 5 to 2 T. The TAC magnet uses saturated iron to restrict the fringe...

  4. Medical Imaging: ECE-4BF3 Michael D. Noseworthy, Ph.D., P.Eng.

    E-Print Network [OSTI]

    Haykin, Simon

    acquisition and formation; post-processing for magnetic resonance imaging and spectroscopy; comparisons Objectives This course is designed to allow students to become familiar with medical imaging technologies applications with other imaging modalities (e.g. PET, SPECT, ultrasound, mammography, CT, EEG, MEG

  5. Notes for completing MRI screening Forms. rev 09-2006 Page 1 of 4 UCSD Center for Functional MRI September, 2006

    E-Print Network [OSTI]

    California at San Diego, University of

    , tens unit, bone stimulator, insulin or other medication pump, automatic defibrillator, internal pacing, medicated pain relief patch) 21. Yes No Do you wear a hearing aid or dentures? #12;Notes for completing MRI

  6. Relationship to CCEFP strategy ! MRI Compatible Robot with an Active Cannula!

    E-Print Network [OSTI]

    Webster III, Robert James

    construction cost, zero maintenance) Test bed to the center: MRI scanners (3 at Vanderbilt and one at Georgia invasiveness. " " " " " · Constructed first (non-MRI compatible) prototype · Prototype construction underway.c.cardona@vanderbilt.edu http://research.vuse.vanderbilt.edu/MEDLab/index.htm ! Motivation! Challenges! · Must use components

  7. Technical Note Comparing event-related and epoch analysis in blocked design fMRI

    E-Print Network [OSTI]

    Henson, Rik

    Technical Note Comparing event-related and epoch analysis in blocked design fMRI Andrea Mechelli August 2002 Abstract In this study we demonstrate that, even in blocked design fMRI, an event-related analysis may provide a more accurate model of the hemodynamic responses than an epoch-related analysis

  8. System for Prostate Brachytherapy and Biopsy in a Standard 1.5 T MRI Scanner

    E-Print Network [OSTI]

    Atalar, Ergin

    System for Prostate Brachytherapy and Biopsy in a Standard 1.5 T MRI Scanner Robert C. Susil,1-dose-rate (HDR) prostate brachytherapy and needle biopsy in a standard 1.5 T MRI scan- ner is demonstrated transperineal catheters for HDR brachytherapy. Mean needle-placement accuracy was 2.1 mm, 95% of needle

  9. Spatiotemporal Dynamics of the BOLD fMRI Signals: Toward Mapping Submillimeter Cortical Columns Using

    E-Print Network [OSTI]

    Duong, Timothy Q.

    . To address these issues, gradient- echo BOLD fMRI studies were performed at 4.7 T and 9.4 T using the well, the initial "metabolism-based" deoxyhemoglobin signal increase was reported to be spatially confinedMRI technique, which is based on similar hemodynamic and metabolic principles for detection of neuronal activity

  10. A Generic Machine-Learning Tool for Online Whole Brain Classification from fMRI

    E-Print Network [OSTI]

    Koppel, Moshe

    A Generic Machine-Learning Tool for Online Whole Brain Classification from fMRI Ori Cohen1 generic machine learning (ML) tool for real- time fMRI whole brain classification, which can be used informa- tion gain for isolating the most relevant voxels in the brain and a support vector machine

  11. Optimization of experimental design in fMRI: a general framework using a genetic algorithm

    E-Print Network [OSTI]

    that outperform random designs on all three criteria simultaneously. © 2003 Elsevier Science (USA). All rights of fMRI designs using novel criteria or existing criteria for design fitness (e.g., Dale, 1999; FristonOptimization of experimental design in fMRI: a general framework using a genetic algorithm Tor D

  12. MULTI-SUBJECT DIFFUSION MRI TRACTOGRAPHY VIA A HOUGH TRANSFORM GLOBAL APPROACH

    E-Print Network [OSTI]

    MULTI-SUBJECT DIFFUSION MRI TRACTOGRAPHY VIA A HOUGH TRANSFORM GLOBAL APPROACH By Iman Aganj://www.ima.umn.edu #12;Multi-subject Diffusion MRI Tractography via a Hough Transform Global Approach Iman Aganj,1 of California-Los Angeles, Los Angeles, CA, USA Introduction: Multi-subject tractography in Diffusion

  13. ERP and fMRI correlates of retrieval cues in episodic memory

    E-Print Network [OSTI]

    Henson, Rik

    1 ERP and fMRI correlates of retrieval cues in episodic memory A Thesis submitted to University. Leun Otten 2006 #12;2 Abstract EEG event-related potentials (ERPs) and fMRI blood oxygenation level.g. Robb & Rugg, 2002) by showing that retrieval orientation effects are robust ERP effects across

  14. MRI-free neuronavigation for transcranial magnetic stimulation in severe depression

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    MRI-free neuronavigation for transcranial magnetic stimulation in severe depression Beno^it Comb-35043 Rennes, France d Pontchaillou Univ. Hospital, Department of Neurosurgery, F-35033 Rennes, France e Syneika, F-35000 Rennes, France Abstract. This paper presents a MRI-free neuronavigation technique

  15. The neural correlates of statistical learning in a word segmentation task: An fMRI study

    E-Print Network [OSTI]

    Aslin, Richard N.

    history: Available online xxxx Keywords: fMRI Statistical learning Word segmentation Artificial language of this statistical learning mechanism in the do- main of language acquisition (see also Saffran, Aslin, & NewportThe neural correlates of statistical learning in a word segmentation task: An fMRI study Elisabeth

  16. Bayesian analysis of single-subject fMRI data: SPM5 implementation

    E-Print Network [OSTI]

    Penny, Will

    Bayesian analysis of single-subject fMRI data: SPM5 implementation William D. Penny, Nelson of single subject fMRI is implemented in SPM5. The algorithm is described in detail in (Penny et al., 2004 coefficients The generative model described in Figure 1 of (Penny et al., 2004) has been updated to allow

  17. EEG-fMRI Fusion of Paradigm-free Activity using Kalman Filtering Thomas Deneux1,3

    E-Print Network [OSTI]

    Faugeras, Olivier

    demand responsible for fMRI signals. Second, it fails in estimating a sparse activity, i.e. presenting

  18. pH-weighted molecular imaging of gliomas using amine chemical exchange saturation transfer MRI.

    E-Print Network [OSTI]

    2015-01-01

    of gliomas using amine chemical exchange saturation transferenhancement mediated chemical exchange saturation transferZu Z, et al. On the origins of chemical exchange saturation

  19. Development, testing, and application of quantitative oxygenation imaging from magnetic susceptibility by MRI

    E-Print Network [OSTI]

    Fan, Audrey Peiwen

    2014-01-01

    The healthy brain consumes 20% of total oxygen used by the body under normal conditions. Continuous oxygen delivery to neural tissue is needed to maintain normal brain function and viability. Reliable measurements of brain ...

  20. MRI-constrained spectral imaging of benzodiazepine modulation of spontaneous neuromagnetic activity in human cortex

    E-Print Network [OSTI]

    Hospital, Finland d Cognitive Brain Research Unit, Department of Psychology, University of Helsinki, Finland e BioMag Laboratory, Engineering Centre, Helsinki University Central Hospital, Finland f Helsinki Brain Research Center, Helsinki, Finland Received 16 May 2006; revised 14 December 2006; accepted 16

  1. Validation of Radiocarpal Joint Contact Models Based On Images from a Clinical MRI Scanner

    E-Print Network [OSTI]

    Johnson, Joshua

    2008-01-01

    Due to the severity and continuing escalation in occurrences of degenerative joint diseases, it is vital to establish a means of detection and prevention that could lead to an improvement in quality of life. One such means ...

  2. SUBSPACE MODELS FOR FUNCTIONAL MRI DATA ANALYSIS Laboratory of Mathematics in Imaging, Department of Radiology

    E-Print Network [OSTI]

    response in the time series and vice versa. Figure 1 illustrates this situation. The shaded areas indicate, Department of Radiology Brigham and Women's Hospital, Harvard Medical School ABSTRACT The models used

  3. Semi-automatic delineation using weighted CT-MRI registered images for

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference) |Janka,Ferrara U./INFN,TaÅŸ,Superconductors(Journal Article)Article)

  4. Resonator coiling in thermoacoustic engines

    SciTech Connect (OSTI)

    Olson, J.R.; Swift, G.W.

    1995-11-01

    Coiling the resonator of a thermoacoustic engine is one way to try to minimize the engine`s size. However, flow in bent pipes is known to alter the fluid flow pattern because of centrifugal forces. Theory and measurements will be presented on the energy dissipation caused by oscillating flow in curved pipes. Measurements have been taken using free oscillations of liquids in U-tubes, and using a thermoacoustic engine with straight and bent resonators. [Work supported by the TTI program of the US Department of Energy, and by the Tektronix Corporation.

  5. Paramagnetic resonance at low fields 

    E-Print Network [OSTI]

    Becker, Stewart

    1954-01-01

    for the absorption, This is the fundamental equation of electron resonance absorption. The character of the resonance will depend on the magnitude of h h X Tj^ compared with unity. Under conditions of "no saturation", that is when $ 0/ *0- * - 0 ? 1, (3U... of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY April 19$h Major Subject: Physics ACKNOWLEDGEMENTS The author wishes to thank Dr. Melvin Eisner for his active interest...

  6. Wavelength-tunable optical ring resonators

    DOE Patents [OSTI]

    Watts, Michael R. (Albuquerque, NM); Trotter, Douglas C. (Albuquerque, NM); Young, Ralph W. (Albuquerque, NM); Nielson, Gregory N. (Albuquerque, NM)

    2011-07-19

    Optical ring resonator devices are disclosed that can be used for optical filtering, modulation or switching, or for use as photodetectors or sensors. These devices can be formed as microdisk ring resonators, or as open-ring resonators with an optical waveguide having a width that varies adiabatically. Electrical and mechanical connections to the open-ring resonators are made near a maximum width of the optical waveguide to minimize losses and thereby provide a high resonator Q. The ring resonators can be tuned using an integral electrical heater, or an integral semiconductor junction.

  7. Wavelength-tunable optical ring resonators

    DOE Patents [OSTI]

    Watts, Michael R. (Albuquerque, NM); Trotter, Douglas C. (Albuquerque, NM); Young, Ralph W. (Albuquerque, NM); Nielson, Gregory N. (Albuquerque, NM)

    2009-11-10

    Optical ring resonator devices are disclosed that can be used for optical filtering, modulation or switching, or for use as photodetectors or sensors. These devices can be formed as microdisk ring resonators, or as open-ring resonators with an optical waveguide having a width that varies adiabatically. Electrical and mechanical connections to the open-ring resonators are made near a maximum width of the optical waveguide to minimize losses and thereby provide a high resonator Q. The ring resonators can be tuned using an integral electrical heater, or an integral semiconductor junction.

  8. Selective enhancement of resonant multiphoton ionization with strong laser fields

    E-Print Network [OSTI]

    Li, Min; Luo, Siqiang; Zhou, Yueming; Zhang, Qingbin; Lan, Pengfei; Lu, Peixiang

    2015-01-01

    High-resolution photoelectron momentum distributions of Xe atom ionized by 800-nm linearly polarized laser fields have been traced at intensities from 1.1*1013 W/cm2 to 3.5*1013 W/cm2 using velocity-map imaging techniques. At certain laser intensities, the momentum spectrum exhibits a distinct double-ring structure for low-order above-threshold ionization, which appears to be absent at lower or higher laser intensities. By investigating intensity-resolved photoelectron energy spectrum, we find that this double-ring structure originates from resonant multiphoton ionization involving multiple Rydberg states of atoms. Varying the laser intensity, we can selectively enhance multiphoton excitation of atomic Rydberg populations. The photoelectron angular distributions of multiphoton resonance are also investigated for the low-order above threshold ionization.

  9. 286 IEEE/ASME TRANSACTIONS ON MECHATRONICS, VOL. 13, NO. 3, JUNE 2008 Evaluation of Electrorheological Fluid Dampers

    E-Print Network [OSTI]

    Mavroidis, Constantinos

    286 IEEE/ASME TRANSACTIONS ON MECHATRONICS, VOL. 13, NO. 3, JUNE 2008 Evaluation magnetic resonance imaging (fMRI), magnetic resonance (MR) compatible robotic/mechatronic systems, mag mechatronic and robotic systems are not suitable for MRI applications, resulting in a need for viable

  10. High-Q Low-Impedance MEMS Resonators

    E-Print Network [OSTI]

    Hung, Li-Wen

    2011-01-01

    piezoelectric micromechanical resonators for UHF applications,"piezoelectric resonators the preferred technology in some applications.Piezoelectric Resonators In pursuit of a solution for applications

  11. Antiferromagnetic resonance excitation by terahertz magnetic field resonantly enhanced with split ring resonator

    SciTech Connect (OSTI)

    Mukai, Y. [Department of Physics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Hirori, H., E-mail: hirori@icems.kyoto-u.ac.jp [Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Yamamoto, T. [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Kageyama, H. [Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Tanaka, K., E-mail: kochan@scphys.kyoto-u.ac.jp [Department of Physics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan)

    2014-07-14

    Excitation of antiferromagnetic resonance (AFMR) in a HoFeO{sub 3} crystal combined with a split ring resonator (SRR) is studied using terahertz (THz) electromagnetic pulses. The magnetic field in the vicinity of the SRR is induced by the incident THz electric field component and excites spin oscillations that correspond to the AFMR, which are directly probed by the Faraday rotation of the polarization of a near-infrared probe pulse. The good agreement of the temperature-dependent magnetization dynamics with the calculation using the two-lattice Landau-Lifshitz-Gilbert equation confirms that the AFMR is excited by the THz magnetic field, which is enhanced at the SRR resonance frequency by a factor of 20 compared to the incident magnetic field.

  12. Ultra-low field magnetic resonance using optically pumped noble gases and SQUID detection

    E-Print Network [OSTI]

    Wong-Foy, Annjoe G.

    2010-01-01

    MRI: Xenon in Triangle of Aerogel MRI: Visualization ofXenon Flow through Aerogel Phosphorous-31 NMR in Phosphorica triangular prism of aerogel. Aerogel is a silicon based,

  13. Dissociative electron attachment to carbon dioxide via the ^2\\Pi_u shape resonance

    E-Print Network [OSTI]

    Moradmand, A; Haxton, D J; Rescigno, T N; McCurdy, C W; Weber, Th; Matsika, Spiridoula; Landers, A L; Belkacem, A; Fogle, M

    2013-01-01

    Momentum imaging measurements from two experiments are presented and interpreted with the aid of new ab initio theoretical calculations to describe the dissociative electron attachment (DEA) dynamics. We address the problem of how the 4 eV ^2\\Pi_u shape resonance in CO_2 proceeds to dissociate to CO(^1\\Sigma^+) + O^-(^2P) by DEA.

  14. Dissociative Electron Attachment to Carbon Dioxide via the 8.2 eV Feshbach resonance

    SciTech Connect (OSTI)

    Slaughter, Dan; Adaniya, Hidihito; Rescigno, Tom; Haxton, Dan; Orel, Ann; McCurdy, Bill; Belkacem, Ali

    2011-08-17

    Momentum imaging experiments on dissociative electron attachment (DEA) to CO{sub 2} are combined with the results of ab initio calculations to provide a detailed and consistent picture of the dissociation dynamics through the 8.2 eV resonance, which is the major channel for DEA in CO{sub 2}. The present study resolves several puzzling misconceptions about this system.

  15. 2005 Special Issue Stochastic resonance in noisy spiking retinal and sensory neuron models*

    E-Print Network [OSTI]

    Kosko, Bart

    2005 Special Issue Stochastic resonance in noisy spiking retinal and sensory neuron models* Ashok Patel, Bart Kosko* Department of Electrical Engineering, Signal and Image Processing Institute of spiking retinal neurons and spiking sensory neurons. The first theorem gives necessary and sufficient

  16. Model for resonant plasma probe.

    SciTech Connect (OSTI)

    Warne, Larry Kevin; Johnson, William Arthur; Hebner, Gregory Albert; Jorgenson, Roy E.; Coats, Rebecca Sue

    2007-04-01

    This report constructs simple circuit models for a hairpin shaped resonant plasma probe. Effects of the plasma sheath region surrounding the wires making up the probe are determined. Electromagnetic simulations of the probe are compared to the circuit model results. The perturbing effects of the disc cavity in which the probe operates are also found.

  17. Microfabricated teeter-totter resonator

    DOE Patents [OSTI]

    Adkins, Douglas Ray; Heller, Edwin J.; Shul, Randy J.

    2004-11-23

    A microfabricated teeter-totter resonator comprises a frame, a paddle pivotably anchored to the frame by pivot arms that define an axis of rotation, a current conductor line on a surface of the paddle, means for applying a static magnetic field substantially perpendicular to the rotational axis and in the plane of the paddle, and means for energizing the current conductor line with an alternating current. A Lorentz force is generated by the interaction of the magnetic field with the current flowing in the conductor line, causing the paddle to oscillate about the axis of rotation. The teeter-totter resonator can be fabricated with micromachining techniques with materials used in the integrated circuits manufacturing industry. The microfabricated teeter-totter resonator has many varied applications, both as an actuation device and as a sensor. When used as a chemical sensor, a chemically sensitive coating can be disposed on one or both surfaces of the paddle to enhance the absorption of chemical analytes from a fluid stream. The resulting mass change can be detected as a change in the resonant frequency or phase of the oscillatory motion of the paddle.

  18. Mechanical quantum resonators A. N. Cleland

    E-Print Network [OSTI]

    Geller, Michael R.

    Mechanical quantum resonators A. N. Cleland and M. R. Geller Department of Physics, University based on the integration of GHz-frequency mechanical resonators with Josephson phase qubits, which have

  19. NANOSCALE OPTICAL COMPUTING USING RESONANCE ENERGY

    E-Print Network [OSTI]

    Lebeck, Alvin R.

    OPTICAL COMPUTING USING RESONANCE ENERGY TRANSFER LOGIC A NEW NANOSCALE DEVICE BASED ON A SINGLE-MOLECULE OPTICAL PHENOMENON CALLED RESONANCE ENERGY TRANSFER- molecule optical devices called chromo- phores. In isolation, a given chromophore absorbs photons

  20. Piezoelectric MEMS resonator characterization and filter design

    E-Print Network [OSTI]

    Kang, Joung-Mo, 1978-

    2004-01-01

    This thesis presents modeling and first measurements of a new piezoelectric MEMS resonator developed at Draper Laboratory. In addition, some simple filter designs incorporating the resonator with predicted performance ...