Association of Iron Deposition in Early-Stage Multiple Sclerosis Lesion with Remyelination Capacity: chi-separation imaging study

Motivation: In multiple sclerosis (MS) lesion, factors influencing myelin dynamics and future remyelination are under active investigation. Goal(s): To assess dynamic changes of MS lesions from their early stage and explore the factors related to their future remyelination outcomes. Approach: Longitudinal changes of MRI phenotypes in MS lesions were assessed from their early stage, particularly focusing on longitudinal alternations in diamagnetic myelin and paramagnetic iron signals using susceptibility source-separation (chi[𝜒]-separation). . Results: 26 lesions show remyelination and 36 did not. The hyperintensity in paramagnetic iron signal (hyper-paramagnetic sign, HPS) at early stage of lesion development was significantly associated to future remyelination. Impact: Iron deposition sign in early-stage MS lesion, which detected by added sensitivity of 𝜒-separation to iron and myelin, can offer potential imaging marker for the impaired remyelination capability in MS pathology.