Accuracy of the central vein sign evaluation by brain MRI for the pathologic characterization of multiple sclerosis cases with markers of "better explanation" of the diagnosis.

The nature of the central nervous system (CNS) white matter (WM) lesions observed in multiple sclerosis (MS) is inflammatory-demyelinating (I-D) and located around a venule, whereas WM lesions of primary small vessel disease migraine and systemic autoimmune diseases with neurological involvement are mainly ischemic and periarteriolar. By T2* MRI sequences a vein can be visualized in about 75% of the MS WM-ID lesions (the ccentral vein, CV, sign), while in the above mentioned diseases this frequency is lower than 50%. In order to evaluate differences in lesion pathology and pathogenic mechanisms, In the present study the CV sign was compared in MS and in MS patients with clinical, laboratory or MRi markers of “better explanation” of the diagnosis (MS-plus) not meeting the criteria of another disease. The high frequency of non perivenular WM lesions observed in most of the MS-plus suggests a non I-D underlying pathology. On the basis of the associated red flags,the main pathogenic mechanisms generating these lesions seems ischemic, probably due to primary CNS vasculitis of the small vessels. The frequency of WM lesions showing the CV sign is a useful marker for improving the accuracy of the MS diagnositic criteria.