Correlation between magnetic resonance images and draining patterns in dural arteriovenous fistulas with leptomeningeal venous drainage.

Abstract

To compare abnormal intensity areas on intracranial magnetic resonance images (MRI) and the pattern of venous drainage in dural arteriovenous fistulas (DAVFs) with retrograde venous drainage. Thirteen patients with retrograde venous drainage of DAVFs were divided into two groups based on the venous drainage pattern determined by detailed angiographic and MRI study. In group 1 there was an accessory route draining into another sinus besides the main draining sinus. In group 2 no such accessory route was present. In group 1 patients (n = 8), MRI detected no unusual intensity areas; 5 patients in this group had episodes of bleeding. Angiographically, in this group retrograde venous drainage tended to occur via multiple varices. On the other hand, none of the 5 group 2 patients experienced a bleeding episode. Angiographically, there was a low incidence of varices. On T2-weighted images, these patients had a hyperintensity area. Following treatment, these areas of abnormality disappeared on T2-weighted MRI. Among 13 patients with DAVFs which drained retrogradely, those with a variceal accessory route (Group 1, n = 8) had a higher incidence of haemorrhage. In patients without such an accessory route (Group 2, n = 5) abnormal signal intensity on MRI was indicative of venous congestion. Continuous-mode angiography and MRI study were useful in the precise identification of DAVFs with a venous drainage route.