9.4T MRI-derived Myelin Water Fraction in post-mortem brain supports the identification of active remyelination in Multiple Sclerosis

Motivation: identifying remyelination in MS is essential for understanding its underlying biological processes, and developing new regenerative treatments. Goal(s): to assess spatial association between ultra-high-resolution Myelin Water Fraction (MWF) and tissue histology during remyelination. Approach: MWF was derived based on multi-Echo-T2-w MRI at 9.4T on four post-mortem brain blocks. Potential remyelination was identified through immunohistochemistry (IHC) by staining myelin basic protein (MBP) and actively remyelinating oligodendrocytes (BCAS1+). Changes in MWF were then compared with the corresponding IHC. Results: increased MWF signal was observed in the ROIs of remyelination . In one actively remyelinating cortical lesion, an increased MWF signal colocalized with actively remyelinating BCAS1+ oligodendrocytes. Impact: An unprecedented MWF with ultra-high spatial resolution obtained in post-mortem brain blocks imaged 9.4T MRI enabled the detection of ongoing remyelination at an almost cellular level, opening a new window into repair mechanisms in MS.