"Venous congestion" as a cause of subcortical white matter T2 hypointensity on magnetic resonance images.

Subcortical T2 hypointensity is an uncommon finding seen in very limited conditions such as multiple sclerosis, Sturge-Weber syndrome, and meningitis. Some of the conditions such as moyamoya disease, severe ischemic-anoxic insults, early cortical ischemia, and infarcts are of "arterial origin." We describe two conditions in which "venous congestion" plays a major role in T2 hypointensity - cerebral venous sinus thrombosis (CVST) and dural arteriovenous fistula (dAVF). The third case is a case of meningitis, showing T2 hypointensity as well, and can be explained by the "venous congestion" hypothesis. The same hypothesis can explain few of the other conditions causing subcortical T2 hypointensity.