['Leptomeningeal contrast enhancement (LM CE) has been recently described in multiple sclerosis (MS) patients as a potential in vivo marker of cortical pathology.', 'To investigate the association of LM CE and development of cortical atrophy in 50 MS patients (27 relapsing-remitting (RR) and 23 secondary-progressive (SP)) followed for 5\u2009years.', 'The presence and number of LM CE foci were assessed only at the 5-year follow-up using three-dimensional (3D) fluid-attenuated inversion recovery magnetic resonance imaging (MRI) sequence obtained 10\u2009minutes after single dose of gadolinium injection on 3T scanner. The percentage change in whole brain, cortical and deep gray matter (GM) volumes, and lesion volume (LV) was measured between baseline and the 5-year follow-up.', 'In total, 25 (50%) of MS patients had LM CE at the 5-year follow-up. Significantly more SPMS patients (12, 85.7%) had multiple LM CE foci, compared to those with RRMS (2, 18.2%) (p\u2009=\u20090.001). MS patients with LM CE showed significantly greater percentage decrease in total GM (-3.6% vs -2%, d\u2009=\u20090.80, p\u2009=\u20090.006) and cortical (-3.4% vs -1.8%, d\u2009=\u20090.84, p\u2009=\u20090.007) volumes and greater percentage increase in ventricular cerebrospinal fluid (vCSF) volume (22.8% vs 9.9%, d\u2009=\u20090.90, p\u2009=\u20090.003) over the follow-up, compared to those without.'] Is leptomeningeal contrast enhancement associated with progression of cortical atrophy in MS : A retrospective , pilot , observational longitudinal study?