Exploring (peri-) lesional and structural connectivity tissue damage through T1/T2-weighted ratio in iron rim multiple sclerosis lesions

Abstract

ObjectiveIn multiple sclerosis (MS), iron rim lesions (IRLs) on magnetic resonance imaging (MRI) are associated with pronounced intralesional tissue damage. The aim of this study was to investigate (peri-)lesional and structural connectivity tissue damage in IRLs compared to non-IRLs. Material and methodsMRI was acquired on a 3 T system. Tissue integrity was assessed using the T1/T2-weighted (T1/T2w) ratio. Furthermore, we assessed the impact on structural network connectivity accounting for differences in lesion volumes and T1/T2w values. ResultsSeventy-six patients (38 with at least one IRL and 38 age- and sex-matched patients without IRLs) were included. In the IRL-group, T1/T2w ratios of IRLs were significantly lower compared to non-IRLs (p < 0.05). When comparing the T1/T2w ratios in non-IRLs between the IRL-group and non-IRL group, there was no significant difference (p = 0.887). We observed a centrifugal decrease in microstructural damage from lesions to the perilesional white matter. In the IRL-group, T1/T2w ratios in the perilesional white matter 3–8 mm distant to the lesion were significantly lower in IRLs compared to non-IRLs. We found no significant differences in the amount of network disruption between both lesion types (p = 0.122). ConclusionT1/T2w represents an interesting candidate to capture a pronounced intra- and perilesional tissue damage of IRLs. However, our preliminary results suggest that a pronounced tissue damage might not result in a higher disruption to structural connectivity networks in IRLs.