MR Detection of Dilated Deep Medullary Veins in Intracranial Dural Arteriovenous Fistulas with retrograde Leptomeningeal Venous Drainage.

SUMMARY: Patients with dural arteriovenous fistula (DAVF) are at higher risk of developing neurological deficits when there is retrograde leptomeningeal venous drainage. Our aim is to demonstrate the presence of dilated deep medullary veins in the brain on magnetic resonance imaging (MR) in this group of patients, and to assess their clinical significance. Nine patients with angiographically proven DAVF associated with leptomeningeal venous drainage who had MR before treatment were studied.MR was performed in at least two orthogonal planes before and after gadolinium administration. The dural fistula was located at the cavernous sinus in five patients, at the transverse-sigmoid sinus in three and at the tentorium in one. Dilated deep medullary veins were noted in six patients. Of these, four showed parenchymal abnormalities which included intracerebral haematoma, venous infarction, brain oedema and T2 hyperintensity in brainstem. Venous varix was present in one patient. No neurological complication or parenchymal change was observed in the three patients without dilated deep medullary veins. Therefore, in patients with intracranial DAVF associated with leptomeningeal venous recruitment, the MR finding of dilated deep medullary veins suggests a more severe degree of venous hypertension and congestion in the brain. This subgroup of patients has a much higher chance of neurological complications and warrants urgent intervention.