Date of Award

2012

Degree Type

Dissertation

Department

Chemical and Biomedical Engineering

First Advisor

Setser, Randolph

Subject Headings

Heart -- Magnetic resonance imaging, Heart -- Fibrosis

Abstract

Identifying and quantifying diffuse myocardial fibrosis is important to provide insights into the relationship between myocardial fibrosis, diastolic and systolic dysfunction, as well as clinical outcomes. T1 mapping is a promising technique for noninvasively identifying diffuse myocardial fibrosis in heart failure. A quantitative T1 map provides sensitivity to the full range of T1 values and is advantageous over the traditional T1-weighted imaging by reducing the reliance on visual interpretation of the signal intensity in the myocardium. However, in-vivo myocardial T1 quantification is challenging because of cardiac and respiratory motion. During the past few years, a variety of T1 mapping techniques, including the modified Look Locker inversion recovery (MOLLI) sequence, have been developed and optimized to measure the myocardial T1 value. Importantly, there have been significant differences between the T1 values determined by various methods, and several aspects of T1 mapping are incompletely understood. The accuracy of T1 mapping is sensitive to several confounding factors, such as the types of T1 mapping acquisition sequence and individual physiologic parameters. It also remains unclear if myocardial T1 values are constant throughout the cardiac cycle or the cyclic variation from the error of the variable flip angle (VFA) technique. Lastly, it is necessary to validate these techniques against the endomyocardial biopsy. The work intends to validate several aspects of T1 mapping. Firstly, whether there is significant cyclic variation of myocardial T1 at 1.5T was assessed in healthy volunteers and patients without myocardial disease. Secondly, a fast 3D DFA technique with B1 correction was developed to measure T1 comparably with gold standard in a wide range of T1 values, which showed it is necessary to incorporate B1 correction at 3T. Thirdly, Look Locker and MOLLI were compared to evaluate their agreement and difference in 3 patient groups precontrast and postcontrast situations. Finally, the T1 mapping tec

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