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

Objective. To compare abnormal intensity areas on intracranial magnetic res onance images (MRI) and the pattern of venous drainage in dural arterioveno us fistulas (DAVFs) with retrograde Venous drainage. Methods. Thirteen patients with retrograde venous drainage of DAVFs were di vided into two groups based on the venous drainage pattern determined by de tailed 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 Results. In group 1 patients (n = 8), MRI detected no unusual intensity are as; 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-weig hted images, these patients had a hyperintensity area. Following treatment, these areas of abnormality disappeared on T2-weighted MRI. Conclusion. Among 13 patients with DAVFs which drained retrogradely, those with a variceal accessory route (Group I, n = 8) had a higher incidence of haemorrhage. In patients without such an accessory route (Group 2, n = 5) a bnormal signal intensity on MRI was indicative of venous congestion. Contin uous-mode angiography and MRI study were useful in the precise identificati on of DAVFs with a venous drainage route.