Periventricular venous density in multiple sclerosis is inversely associated with T2 lesion count: a 7 Tesla MRI study

Background: Damage to venules in multiple sclerosis was first described decades ago. Today, ultrahigh magnetic field strength T2*-weighted magnetic resonance imaging (MRI) techniques depict very small cerebral veins in vivo with great anatomical detail. Objective: We aimed to investigate alterations of periventricular small blood vessel appearance in relation to T2 lesion count and distribution in multiple sclerosis and clinically isolated syndrome in comparison with healthy control subjects at 7 Tesla MR1. Methods: We investigated 38 patients (including 16 with early multiple sclerosis and seven with clinically isolated syndrome) and 22 matched healthy controls at 7 Tesla.The protocol included T2*-weighted Fast Low Angle Shot, and T2-weighted Turbo Inversion Recovery Magnitude sequences.We quantified periventricular venous density by a novel regionof-interest-based algorithm, expressing the ratio of 'veins per region-of-interest' as well as of `periventricular vascular area'. Results: Our study revealed significantly decreased venous density in multiple sclerosis patients compared with healthy controls.Venous alterations were already detectable in clinically isolated syndrome and early multiple sclerosis,although to a smaller extent.Venous density correlated inversely with periventricular and whole-brain T2 lesion count. Furthermore, we found no indication for cerebral venous congestion in multiple sclerosis. Conclusion: High spatially resolving anatomical Tr*-weighted MRI revealed vascular alterations in early stages of multiple sclerosis, presumably as a part of widespread haemodynamic and metabolic alterations.