Novel ultrahigh resolution data acquisition and image reconstruction for multi-detector row CT

Journal Article · Tue May 15 04:00:00 EDT 2007 · Medical Physics

DOI:https://doi.org/10.1118/1.2722872· OSTI ID:20951302

Flohr, T G; Stierstorfer, K; Suess, C; Schmidt, B; Primak, A N; McCollough, C H ^[1]

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1. Siemens Medical Solutions, Computed Tomography CTE PA Siemensstr. 1, 91301 Forchheim (Germany) and Department of Diagnostic Radiology, Eberhard-Karls-Universitaet Tuebingen (Germany)

We present and evaluate a special ultrahigh resolution mode providing considerably enhanced spatial resolution both in the scan plane and in the z-axis direction for a routine medical multi-detector row computed tomography (CT) system. Data acquisition is performed by using a flying focal spot both in the scan plane and in the z-axis direction in combination with tantalum grids that are inserted in front of the multi-row detector to reduce the aperture of the detector elements both in-plane and in the z-axis direction. The dose utilization of the system for standard applications is not affected, since the grids are moved into place only when needed and are removed for standard scanning. By means of this technique, image slices with a nominal section width of 0.4 mm (measured full width at half maximum=0.45 mm) can be reconstructed in spiral mode on a CT system with a detector configuration of 32x0.6 mm. The measured 2% value of the in-plane modulation transfer function (MTF) is 20.4 lp/cm, the measured 2% value of the longitudinal (z axis) MTF is 21.5 lp/cm. In a resolution phantom with metal line pair test patterns, spatial resolution of 20 lp/cm can be demonstrated both in the scan plane and along the z axis. This corresponds to an object size of 0.25 mm that can be resolved. The new mode is intended for ultrahigh resolution bone imaging, in particular for wrists, joints, and inner ear studies, where a higher level of image noise due to the reduced aperture is an acceptable trade-off for the clinical benefit brought about by the improved spatial resolution.

• OSTI ID: 20951302
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 5 Vol. 34; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
AUDITORY ORGANS
COMPUTERIZED TOMOGRAPHY
DATA ACQUISITION
IMAGE PROCESSING
IMAGES
PHANTOMS
RADIATION DOSES
SKELETON
SPATIAL RESOLUTION
TANTALUM
TRANSFER FUNCTIONS