The characteristics and influencing factors of paramagnetic rim lesions in Chinese MS patients: A 7T MRI study

Paramagnetic rim lesions (PRLs) in multiple sclerosis (MS) are a significant factor for disability progression and prognosis, but their characteristics in the Chinese population are unclear. To explore PRLs in Chinese MS patients using 7T magnetic resonance imaging (MRI), including their number, proportion, distribution, and associated factors. Patients from the 7T MRI subgroup of the China National Registry of Neuro-Inflammatory Diseases (CNRID) were prospectively included. PRLs were assessed on susceptibility-weighted imaging (SWI)-phase images. Patients were grouped by PRL count (0, 1-3, 4-10, >10). Associations between clinical characteristics and PRL count were analyzed using multivariable linear regression, while correlations with disease duration were assessed using Pearson partial correlation and regression. Among 110 participants, 96 (87.3%) had at least one PRL. In PRL groups, proportions were 12.7%, 20.0%, 29.1%, and 38.2%. PRL count positively correlated with Expanded Disability Status Scale (EDSS), total lesion count, and volume and negatively with Symbol Digit Modality Test (SDMT; p < 0.05). Longer disease duration was associated with a lower PRL proportion after adjusting for age and sex (β = -0.006, p = 0.032). A high proportion of Chinese MS patients in our 7T MRI cohort had PRLs, with many exhibiting multiple PRLs (⩾4). PRL count was influenced by EDSS, SDMT, total lesion count, and volume, while PRL proportion negatively correlated with disease duration.