Central vein sign differentiates MS from CNS inflammatory vasculopathies.

OBJECTIVES: In multiple sclerosis (MS), MRI is a sensitive tool for detecting white matter lesions, but its diagnostic specificity is still suboptimal; ambiguous cases are frequent in clinical practice. Detection of perivenular lesions in the brain (the "central vein sign") improves the pathological specificity of MS diagnosis, but comprehensive evaluation of this MRI biomarker in MS-mimicking inflammatory and/or autoimmune diseases, such as CNS inflammatory vasculopathies, is missing. In a multicenter study, we assessed the frequency of perivenular lesions in MS vs. systemic autoimmune diseases with CNS involvement and primary angiitis of the CNS (PACNS). METHODS: In 31 patients with inflammatory CNS vasculopathies and 52 with relapsing-remitting MS, 3D-T2*-weighted and T2-FLAIR images were obtained during a single MRI acquisition after gadolinium injection. For each lesion, the "central vein sign" was evaluated according to consensus guidelines. For each patient, lesion count, volume, and brain location, as well as fulfillment of dissemination in space MRI criteria, were assessed. RESULTS: MS showed higher frequency of perivenular lesions (median 88%) than did inflammatory CNS vasculopathies (14%), without overlap between groups or differences between 3T and 1.5T MRI. Among inflammatory vasculopathies, Behçet disease showed the highest median frequency of perivenular lesions (34%), followed by PACNS (14%), antiphospholipid syndromes (12%), Sjögren's syndrome (11%), and systemic lupus erythematosus (0%). When a threshold of 50% perivenular lesions was applied, CVS discriminated MS from inflammatory vasculopathies with diagnostic accuracy of 100%. INTERPRETATION: The "central vein sign" differentiates inflammatory CNS vasculopathies from MS at standard clinical magnetic field strengths. This article is protected by copyright. All rights reserved.