Running head: T2 MRI spectra of myelin in MS lesions Number of characters in the title = 84 (with spaces); in the running head = 38; Number of words in the abstract = 241; in the body of manuscript = 3097 Number of figures = 4; color figures = 1; tables = 1.
Zhang et al 2
AbstractObjective: Lesions with different types of pathology are found at autopsy in multiple sclerosis (MS). The goal of this study was to determine lesion characteristic in MRI using clinical protocols.Methods: We imaged fresh brain specimens from 21 MS patients using 1.5T scanners and applied image texture analysis. Through staining of tissue sections for inflammation (microglia and microphages) and myelin (proteolipid protein), MS lesions were classified into 5 categories: pre-active, active, chronic active, chronic inactive, and remyelinated.Based on standard T2-weighted images, texture analysis was performed using a local spatial frequency-based approach that provided multi-scale MR spectra at each voxel.Results: Following linear mixed-effect modeling, we found that normalized MRI texture heterogeneity was greater in active, chronic active, and chronic inactive lesions that had complete demyelination than in normal appearing white matter (NAWM; p < 0.01). In combination, these 3 lesion types as a group were more heterogeneous than pre-active (p = 0.02) lesions and NAWM (p < 0.01), both with apparently intact myelin. Furthermore, the distribution of remyelinated spectra was similar to that of NAWM but different from demyelinated lesions (p < 0.01).Interpretation: While the 5 defined tissue categories not completely distinguishable at 1.5T, we differentiated demyelination from remyelination and discovered that changes in myelin content drove the severity of texture abnormality. Assessing local patterns of image spectra in clinical MRI may become a useful approach in determining the efficacy of remyelination strategies in MS and other demyelinating disorders (241).Zhang et al 3