Measurement of flow through porous media by magnetic resonance imaging
Quantitative imaging of flow through porous media is possible utilizing pulsed gradient phase encoding techniques in MRI (magnetic resonance imaging). The random directional motion of the fluid in a porous medium causes signal attenuation due to the dispersion of the phase information when velocity phase encoding gradient pulses are applied. Isolation of the effect of molecular diffusion process which is random not only in space but also in time in achieved by acquiring images with velocity compensated gradient pulses for measurement of the diffusion constant. PFOB (perfluorooctyl bromide) was used as an intravascular contrast agent in the experiments on the rabbit kidney models for extraction of all available information about the parameters governing the microvascular flow process in one MRI setup. A pulse sequence program was developed on a 1.5 T whole body MRI system to incorporate the multislice data collection, chemical-shift artifact correction, and cardiac gating algorithms. The complete imaging setup also included several radio frequency coils for F-19 imaging and an image reconstruction program with a motion artifact suppression algorithm required for collection of flow sensitive images in in-vivo studies. The results obtained from the experiments on the rabbit kidneys verified the proposed formulation for the quantitative analysis of microvascular flow. These studies on the animal models indicated that the measurement of microvascular flow on an absolute scale can be realized using the phase sensitive pulsed gradient velocity encoding methods. Utilization of the measurement and analysis techniques can be possible in the controlled experiments such as monitoring tumor responses to a certain kind of therapy through the evaluation of the microvascular flow.
- Research Organization:
- California Univ., Irvine, CA (United States)
- OSTI ID:
- 5438941
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BLOOD FLOW
NMR IMAGING
QUANTITATIVE CHEMICAL ANALYSIS
KIDNEYS
MAGNETIC RESONANCE
RABBITS
ANIMALS
BODY
CHEMICAL ANALYSIS
DIAGNOSTIC TECHNIQUES
MAMMALS
ORGANS
RESONANCE
VERTEBRATES
550602* - Medicine- External Radiation in Diagnostics- (1980-)
551000 - Physiological Systems