Quantifying longitudinal tract profile differences in multiple sclerosis lesional tracts

Motivation: Region-of-interest analyses of quantitative MRI measures may overlook heterogeneity in tissue microstructure. Tract profiling shows greater detail but is difficult to quantify over time. Goal(s): Quantify differences in lesional tract profiles across two timepoints. Approach: Tract profiles associated with focal lesions of myelin water fraction (MWF) and fractional anisotropy (FA) were created in people with multiple sclerosis (MS) who were scanned at two timepoints twelve months apart. Two measures were proposed to quantify tract profile differences, and were correlated with expanded disability status scale (EDSS) scores. Results: The mean absolute difference in MWF between two timepoints along lesional MS tracts correlated with EDSS. Impact: Differences in lesional tract profiles of myelin water fraction and fractional anisotropy were quantified across two timepoints twelve months apart using two newly proposed measures in people with multiple sclerosis, and showed moderate correlations with clinical scores.