Evaluation of Normalization Methods for apparent Myelin Water Fraction Measurements at Ultra High Field

Motivation: Multiple sclerosis (MS) is characterized by demyelination of the central nervous system. Ultra High Field (UHF) MRI can reveal CNS pathology that is not apparent on conventional MRI in MS patients, but options for measuring myelin density are limited. Goal(s): Calculation of MWF using ViSTa map requires intensity normalization. We evaluate normalization approaches for visualization of short transverse relaxation time component (ViSTa), a semiquantitative measure of apparent myelin water fraction (aMWF). Approach: We compare two types of normalization scan - a turboflash (TFL) and a gradient recalled echo (GRE) on MS patients. Results: We find that normalization with GRE provides better conspicuity of lesions. Impact: Characterization of myelin density has the potential to supplement UHF approaches to evaluating MS.