Dura mater enhancement on 3T MRI is associated with cortical lesion burden in multiple sclerosis

Background: Post-contrast FLAIR MRI can demonstrate meningeal signal enhancement in people with multiple sclerosis (pwMS), including enhancement along the leptomeninges and dura mater. Although these enhancement patterns have been variably interpreted as reflecting inflammatory processes, their biological specificity and relationship to cortical lesion pathology remain uncertain. Objective: To evaluate the association between cortical lesion burden and distinct patterns of meningeal enhancement (ME), including dura mater enhancement (DME), leptomeningeal enhancement (LME), and meningeal perivascular enhancement (MPVE) on MRI in pwMS. Methods: 214 pwMS (173 relapsing–remitting, 41 progressive) underwent 3T MRI including 3D FLAIR pre- and post-contrast, and subtraction imaging. ME (LME + DME) and MPVE were visually classified. Cortical lesions were quantified using a validated multi-modal approach incorporating MMCLE, FLAIR-squared, AI-DIR, and T1/T2 ratio maps, with expert verification. Analyses were adjusted for age, sex, disease duration, disease subtype, and disease-modifying treatment, and corrected for multiple comparisons. Results: 142 (66.4%) pwMS showed combined ME/MPVE, 121 (56.5%) ME, including 97 (45.3%) with DME and 48 (22.4%) with LME. Additionally, 46 (21.5%) exhibited MPVE. A higher prevalence and frequency of LME + pwMS were observed in older age groups (p = 0.002), whereas no such age-related pattern was found for DME + or MPVE + pwMS. DME + pwMS showed greater cortical lesion number (9.6 vs. 4.9, p = 0.003) and volume (374.1 mm³ vs. 187.6 mm³, p = 0.019) compared to DME − pwMS. DME frequency correlated with cortical lesion number (r = 0.59, p < 0.001) and volume (r = 0.56, p < 0.001). Stepwise regression identified DME as an independent predictor of cortical lesion number (β = 0.45, p < 0.001) and volume (β = 0.41, p < 0.001), explaining 12–15% of variance beyond conventional MRI measures. Conclusions: DME on 3T MRI is associated with increased cortical lesion burden in pwMS.