Longitudinal Analysis of [11C]DPA-713 PET and QSM in Multiple Sclerosis for Differentiating the Spatial Patterns of Pathological Lesions

Motivation: Our understanding of paramagnetic rim lesions (PRLs) formation remains incomplete. Goal(s): Our goal was to identify spatial patterns of inflammatory changes in early lesion development and to examine their association with PRL formation. Approach: We performed a longitudinal analysis of multiple sclerosis lesions using a multi-parametric approach with a second generation TSPO PET ligand (11C DPA713) and QSMp at the lesion level. Results: We observed distinct spatial pattern in newly developed PRLs with increasing activity in the lesion center. Moreover, early spatial innate immune activity of PRLs shows high correlation with eventual iron deposition in follow-up. Impact: Our analysis suggests that the early-stage inflammatory activity in the lesion center is associated with the development of a paramagnetic rim.