Leptomeningeal inflammation (LMI) in multiple sclerosis (MS) can be putatively identified by leptomeningeal contrast enhancement (LMCE) on gadolinium-enhanced 3D T2-fluid attenuated inversion recovery (FLAIR) magnetic resonance (MR) images. 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.
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.
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. Analysis of covariance (ANCOVA) and regression models were used to assess the relationship between MRI variables and clinical variables, controlling for age.
24% of MS patients revealed LMCE, and 47% and 24% revealed DME/FCE and VWE, respectively. LMCE presence correlated with age and higher ventricular cerebrospinal fluid (vCSF) volume. More LMCE positive subjects (38%) showed additional VWE, compared to LMCE negative subjects (20%, p=0.055). DME/FCE presence was associated with higher T1/T2 lesion load, higher vCSF volume and decreased total deep gray matter (GM) and hippocampus volumes. All three meningeal enhancement patterns showed a high persistence in shape and size at follow-up.
Different patterns of meningeal enhancement, i.e. LMCE, DME/FCE and VWE can be identified by gadolinium-enhanced 3D FLAIR MR imaging. LMCE positive patients show a trend for higher frequency of VWE than LMCE negative patients. DME/FCE is the most frequent meningeal enhancement pattern in MS, which correlates with imaging markers of lesion burden and brain atrophy and may indicate abnormal lymphatic drainage in these patients.