Investigating ihMT T1D-filtering imaging for characterizing demyelination and inflammation processes in MS lesions

Motivation: Pathological processes following MS lesion formation (demyelination and inflammation) need to be better characterized. Goal(s): Investigating ihMT T1D filters as semi-quantitative markers of demyelination and inflammation in MS lesions. Approach: The relation between ihMT T1D filters and the density of myelin [My] and other motion-restricted macromolecules (e.g., macrophages) [Mm] was exploited to derive [My] and [Mm] images in MS patients and evaluate their intensity in MS lesions. Results: Various levels of demyelination and macromolecular density were revealed by [My] and [Mm] signals in lesions. A mismatch between [Mm] and QSM may indicate a sensitivity of ihMT T1D filters to different ranges of macromolecules. Impact: Semi-quantitative measures of the density of myelin and that of other macromolecules can be obtained with a single MR experiment using ihMT T1D filtering. This technique might be used to characterize demyelination and processes of inflammation in MS lesions.