MR Imaging of Intracranial Dural Arteriovenous Fistulae (Dural AVF)

ABSTRACT

PURPOSE: To describe the magnetic resonance (MR) findings of intracranial dural arteriovenous fistulae (DAVF) and associated venous hypertensive diseases, and to determine their diagnostic value. MATERIALS AND METHODS: MR Imagings of twelve cases of angiographically-proven intracranial DAVF were analyzed. The presence of signal voids, dilatation of involved dural sinus, the dilatation of the extra/intradural venous system, high signal intensity on T2 weighted image, cerebral edema, intracranial hemorrhage, and hydrocephalus were retrospectively analyzed. MR findings and angiographic classification were compared. RESULTS: In 11 of 12 patients (92%), MR revealed the location of DAVF. In five cases, these were cavernous, and in six, they were extracavernous; the locations of the latter were as follows superior sagittal sinus (SSS), 4 torcula, 1; lateral sinus & SSS, 1. Except for the lateral sinus lesion, all the DAVF seen in thses 11 patients showed the presence of signal voids and dilatation of the involved dural sinus. Findings of associated venous hypertensive disease, namely dilatation of the superior ophthalmic vein and cortical venous system, cerebral edema, and high signal intensity on T2-weighted images were observed in three cavernous lesions (50%), but all extracavernous DAVF (100%) showed associated venous hypertensive disease. When the grade of angiographic classification was high and reflux of sinus blood to the cortical vein was seen on angiography, the MR findings of intracranial venous hypertension showed good correlation. CONCLUSION: The MR findings of DAVF include dilatation of the dural sinus and signal voids of feeding arteries and draining vein. Other findings which suggest intracranial venohypertensive disease are dilatation of the cortical and medullary vein, hydrocephallus, cerebral edema and intracranial hamorrhage. These and the angiographic findings correlate well and suggest that in the diagnosis of DAVF and the detection of intracanial venohypertension, MR is a non-invasivse technique which can be use be usefully employed before final diagnosis by angiography.