Development of NMR/MRI techniques and chemical models for the study of atherosclerosis
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Case Western Reserve University School of Graduate Studies / OhioLINK
1994
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=case1057263774 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-case10572637742021-08-03T05:31:04Z Development of NMR/MRI techniques and chemical models for the study of atherosclerosis Hua, Jianmin. NMR/MRI techniques chemical models atherosclerosis <p>Three NMR/MRI techniques (catheter receiver probe, asymmetric sampling, and magnetization transfer) and a chemical model system were developed and investigated in this thesis for the study of atherosclerosis.</p><p>Simulations and phantom experiments demonstrate the spatial response of several “inside-out” probe coil designs, including loop, “birdcage,” “multipole,” “center return,” and opposed solenoids. In general, the opposed solenoid design provides substantially superior homogeneity to other designs considered. Canine iliofemoral artery images were acquired using a catheter probe in a whole-body imaging system. <i>In situ</i> (cadaver) images acquired at 78 x 78 micron in-plane resolution delineate intima, media, and adventitia layers of the vessel wall. <i>In vivo</i> images from similar acquisition conditions are poorly resolved, presumably due to motion.</p><p>S/N, artifacts, and resolution of MR images obtained from asymmetrically sampled data are analyzed. Four different schemes for Fourier reconstruction of asymmetric data are considered, combined with two approaches to phase correction; second-order polynomial phase correction is shown to have substantial advantages over the more conventional Fourier phase mapping.</p><p>Also studied are three alternative methods for performing magnetization transfer: continuous wave, “soft” shaped pulses, and binomial pulses. Simulations based on a Bloch equation model show that nominally optimized versions of each of these approaches provide similar image contrast at a constant level of MT power. Experimental results from a whole-body system are generally consistent with simulations, with significant deviations attributed to hardware imperfections. Additionally, an improved method for measuring T<sub>2r</sub> using MT “z-spectra” from a whole-body system was developed.</p><p>Finally, to determine if NMR parameters could be useful for differentiation of atherosclerotic lesions, eleven mixtures of lipid and water, with chemical compositions like human atherosclerotic lesions, were synthesized, and analyzed by four NMR “measures:” T<sub>1</sub>, T<sub>2</sub>, MT ratio M/M<sub>0</sub>, and T<sub>2r</sub>. None of these NMR parameters showed a monotonic variation with lesion progression, although some combination of these parameters may provide a unique assay for staging of atherosclerosis. It remains open to determine if these and/or other NMR method(s) can provide clinically useful characterization of atherosclerosis.</p> 1994 English text Case Western Reserve University School of Graduate Studies / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=case1057263774 http://rave.ohiolink.edu/etdc/view?acc_num=case1057263774 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
NMR/MRI techniques chemical models atherosclerosis |
| spellingShingle |
NMR/MRI techniques chemical models atherosclerosis Hua, Jianmin. Development of NMR/MRI techniques and chemical models for the study of atherosclerosis |
| author |
Hua, Jianmin. |
| author_facet |
Hua, Jianmin. |
| author_sort |
Hua, Jianmin. |
| title |
Development of NMR/MRI techniques and chemical models for the study of atherosclerosis |
| title_short |
Development of NMR/MRI techniques and chemical models for the study of atherosclerosis |
| title_full |
Development of NMR/MRI techniques and chemical models for the study of atherosclerosis |
| title_fullStr |
Development of NMR/MRI techniques and chemical models for the study of atherosclerosis |
| title_full_unstemmed |
Development of NMR/MRI techniques and chemical models for the study of atherosclerosis |
| title_sort |
development of nmr/mri techniques and chemical models for the study of atherosclerosis |
| publisher |
Case Western Reserve University School of Graduate Studies / OhioLINK |
| publishDate |
1994 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=case1057263774 |
| work_keys_str_mv |
AT huajianmin developmentofnmrmritechniquesandchemicalmodelsforthestudyofatherosclerosis |
| _version_ |
1719421168573743104 |