An underlying process causes abnormalities in veins together with MS

[frodo]

This paper points to the existence of an "underlying process" that causes the known MS lesions and, at the same time, some venous problems:

The Central Vein: FLAIR Signal Abnormalities Associated with Developmental Venous Anomalies in Patients with Multiple Sclerosis

http://www.ajnr.org/content/39/11/2007.abstract

CONCLUSIONS: The association of developmental venous anomalies and FLAIR hyperintensities was more common in patients with MS, which suggests that the underlying demyelinating pathologic process of MS may be the cause of this propensity in patients with MS. Impaired venous drainage in the territory of developmental venous anomalies may predispose to development of these lesions, and an associated central vein is helpful in understanding an atypical location of MS plaques.