Advisory Committee Chair
Andreas Anayiotos
Advisory Committee Members
Shastry Akella
Mark Doyle
Roy Koomullil
Donald Twieg
Document Type
Dissertation
Date of Award
2007
Degree Name by School
Doctor of Philosophy (PhD) School of Engineering
Abstract
This study aimed at the numerical simulation of three imaging options in phase contrast magnetic resonance (PC-MR), developed jointly at University of Alabama at Birmingham and Allegheny Research Institute. The three methods were: 1) Fragmented Regional Interpolation Segmentation for K-space (FRISK); 2) Enhanced Temporal Resolution (ETR) technique; and 3) Self Reference (SR) PC-MR. The three methods were tested on various physiologic platforms and the data accuracy and acquisition time savings processed by these methods were directly compared to those processed by conventional (CON) PC-MR. Computational fluid dynamics (CFD) data of: a) two-chamber orifice flow model simulating valvular regurgitation, b) a femoral artery model, and c) a U-shaped model simulating the aortic arch for simulation purposes were generated. FRISK was configured to capture either high temporal information or complexly varying spatial information with a temporal component or a mixture of both. The errors of temporal misregistration of velocity compensated (VC) and velocity encoded (VE) pairs were further eliminated or dramatically reduced by using the ETR option. CON PC-MR requires the knowledge of VC and VE data pairs at each time frame to get the true velocity informaiv tion, which inevitably introduces first-order intrinsic errors caused by the temporal misregistration of the paired data sets. SR PC-MR was conceived to allow the reference scan to be eliminated from the dynamic acquisition. FRISK was shown to maintain or even improve data accuracy while reducing the scan time by at least 50% compared to corresponding CON PC-MR. By adapting the FRISK parameters for flowfields with different features, FRISK was capable of capturing in-plane and through-plane velocity information with excellent detail in approximately 20 heartbeats duration. Compared to the CON PC-MR processed data, the ETR processed data better represented peak velocities (101%±13% vs. 127%±28%, p<0.001) and correlated more closely with the reference (REF) data (r = 0.94±0.05 vs. r = 0.67±0.23, p<0.001). The SR PC-MR data showed significantly better representation of the velocitytime waveform as assessed by lower root-mean-square (RMS) errors (9.0±1.0% vs. 24.0±0.2%, p<0.005). Overestimation of peak velocity was dramatically attenuated using Self Reference compared to the conventional approach (2.8±0.4% vs. 16.9±6.4%, p<0.005). An average of 119.4 ± 26.6 % (p<0.005) SNR was realized in both in vitro and in vivo SR PC-MR data compared to conventional scans.
Recommended Citation
Li, Longchuan, "Numerical And Experimental Study Of Three Imaging Advancements In Phase Contrast Magnetic Resonance Imaging" (2007). All ETDs from UAB. 3746.
https://digitalcommons.library.uab.edu/etd-collection/3746