| Summary: | Magnetization transfer (MT) imaging has emerged as a viable alternative to conventional structural MRI indices. It has been shown to be remarkably sensitive to changes in myelin associated with pathologies such as multiple sclerosis (MS). Previous work has built a solid foundation to study the MT effect in vivo, however, the existing literature falls short of developing methods that may help provide solutions to elucidating the clinical problems associated with MS. Therefore, the overall goal of this dissertation was to further the understanding of quantitative magnetization transfer (qMT) imaging at clinical MRI field strengths to provide solutions to these clinical problems. Since qMT imaging has been shown to be sensitive to myelin pathology, these metrics were translated to areas outside of the brain, into the optic nerve and spinal cord, where radiological changes may be better correlated with clinical disability. Next, the coverage of a new MT imaging method, inhomogeneous magnetization transfer (ihMT) was expanded to cover a large 3D volume in a clinically reasonable scan time. This new acquisition strategy has been shown to be specific to WM, and thus, may provide a better indicator of changes in myelin than traditional MT imaging over a large volume. Finally, the two pool MT model was investigated to devise several different methods â one based on a new acquisition strategy, and one based on a new modeling methodology â to remove effects that confound the signal of interest in chemical exchange saturation transfer (CEST) spectra. In conclusion, qMT has been shown to be a remarkably important technique towards understanding the properties of myelin. Gaining a fundamental understanding of how myelin is affected by pathologies which affect the macromolecular structure of neural tissues may facilitate advances in the way we diagnose, treat, and hopefully cure disease. qMT may provide key contributions to this puzzle, and the studies described here have hopefully laid a foundation to drive these future discoveries.
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