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

Background: 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. Objective: To explore PRLs in Chinese MS patients using 7T magnetic resonance imaging (MRI), including their number, proportion, distribution, and associated factors. Methods: 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. Results: 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). Conclusion: 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.