Leptomeningeal, dura mater and meningeal vessel wall enhancements in multiple sclerosis

Background: Leptomeningeal contrast enhancement (LMCE) has previously shown potential to be an indirect marker for leptomeningeal inflammation in multiple sclerosis (MS). Dura mater (DME), inclusive falx cerebri (FCE) enhancement and meningeal vessel wall enhancement (VWE) represent two other meningeal enhancement patterns in MS that have not been extensively studied. Objectives: To investigate the frequency of LMCE, DME/FCE and VWE in patients with MS and their associations with demographic, clinical and MRI characteristics in a longitudinal retrospective study. Methods: 217 MS patients (193 relapsing-remitting MS, 24 progressive MS) were assessed at baseline and over 18 months follow-up using 3T 3D FLAIR pre- and post-contrast and subtraction images. Lesion and brain volume outcomes were additionally calculated. Analyses were adjusted for age, and corrected for multiple comparisons. Results: LMCE and VWE frequency was associated with higher age (p<0.02), but the presence of DME/FCE was not (p=0.402). 24% of MS patients revealed LMCE and VWE, respectively, and 47% showed DME/FCE. Presence of LMCE, VWE and DME/FCE was not significantly associated with clinical or imaging markers of disease severity. All three patterns of meningeal enhancement showed a high persistence in shape and size at follow-up. Conclusions: LMCE, DME/FCE and VWE can be identified by gadolinium-enhanced 3D FLAIR MR imaging. Meningeal enhancement is associated with higher age. DME/FCE is the most frequent meningeal enhancement pattern in MS, however further case-control studies should determine whether this represents abnormal lymphatic drainage in these patients or is an age-dependent physiologic phenomenon.