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VELOCITY-ENCODED MAGNETIC RESONANCE IMAGING:
ACQUISITION, RECONSTRUCTION AND APPLICATIONS
by
Joao Luiz Azevedo de Carvalho
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Ful llment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(ELECTRICAL ENGINEERING)
August 2008
Copyright 2008 Joao Luiz Azevedo de Carvalho
Object Description
| Title | Velocity-encoded magnetic resonance imaging: acquisition, reconstruction and applications |
| Author | de Carvalho, Joao Luiz Azevedo |
| Author email | jcarvalh@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Electrical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2008-04-24 |
| Date submitted | 2008 |
| Restricted until | Unrestricted |
| Date published | 2008-05-28 |
| Advisor (committee chair) | Nayak, Krishna S. |
| Advisor (committee member) |
Pohost, Gerald M. Leahy. Richard M. Hsiai, Tzung K. |
| Abstract | Cardiovascular disease is the leading cause of death and disability in the United States. An important component of the assessment of cardiovascular disease is the visualization and quantitation of cardiovascular flow. The current gold standard for flow measurement is Doppler ultrasound. However, evaluation by ultrasound is inadequate when there is fat, air, bone, or surgical scar in the acoustic path.; Magnetic resonance imaging (MRI) is a modality uniquely capable of imaging all aspects of heart disease. The evaluation of valvular disease and intracardiac flow will be a necessary capability in a comprehensive cardiac MR examination. However, existing MRI methods for flow quantitation suffer from partial volume effects or poor spatial localization.; This work introduces spiral Fourier velocity encoding (spiral FVE), a new method for rapid and non-invasive measurement of cardiovascular blood flow using MRI. Spiral FVE is uniquely capable of spatially separating static tissue from flowing blood in different vessels, and of measuring multiple flows in a single acquisition.; Spiral FVE can be improved using acceleration techniques such as variable-density spirals, temporal acceleration, and partial Fourier reconstruction. Using these techniques, we demonstrate improvements such as higher spatial resolution, increased velocity field-of-view, reduced off-resonance effects, and higher temporal resolution. These are achieved without increase in scan time, and without introducing significant artifacts.; We also propose a new reconstruction scheme for variable-density FVE, which can be used to achieve higher velocity resolution. The proposed reconstruction approach significantly reduces aliasing artifacts, and can, in principle, be applied to any FVE-based method.; We also show that spiral FVE can be used for non-invasive estimation of carotid fluid shear rate, an important predictor of atherosclerosis. Spiral FVE is uniquely suitable for this application, as it is the only currently available FVE method capable of providing fully-resolved spatial localization in clinically practical scan time.; No MR gold standard exists for assessing valvular disease and carotid fluid shear. Spiral FVE offers full spatial localization and accurate flow quantitation, which are crucial in these applications. Using the proposed acceleration techniques, spiral FVE may be used as a rapid and non-invasive alternative in addressing these important clinical problems. |
| Keyword | FVE; Fourier velocity encoding; MRI flow imaging; aortic stenosis; aortic regurgitation; wall shear stress; carotid artery disease |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Type | texts |
| Legacy record ID | usctheses-m1249 |
| Rights | de Carvalho, Joao Luiz Azevedo |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | http://www.usc.edu/isd/libraries/services/ask_a_librarian/email/ |
| Filename | etd-Carvalho-20080528 |
| Archival file | uscthesesreloadpub_Volume23/etd-Carvalho-20080528.pdf |
Description
| Title | Page 1 |
| Full text | VELOCITY-ENCODED MAGNETIC RESONANCE IMAGING: ACQUISITION, RECONSTRUCTION AND APPLICATIONS by Joao Luiz Azevedo de Carvalho A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Ful llment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (ELECTRICAL ENGINEERING) August 2008 Copyright 2008 Joao Luiz Azevedo de Carvalho |
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