Evaluation of dural arteriovenous fistulas of cavernous sinus before and after endovascular treatment using time-resolved MR angiography.

Digital subtraction angiography (DSA) is the preferred method for confirming dural arteriovenous fistulas (DAVFs), but it has the disadvantage of being invasive. In contrast, time-resolved magnetic resonance angiography (TR-MRA) is a useful, noninvasive imaging technique. The aim of this study was to compare the evaluation of DAVFs of the cavernous sinus (CS) using TR-MRA and DSA. TR-MRA and DSA were obtained in six patients with CS-DAVFs treated with endovascular surgery. TR-MRA and DSA before and after treatment were reviewed by one neuroradiologist without previous knowledge of the existence of CS-DAVFs for the detection and characterization (feeding artery and venous drainage) of CS-DAVFs. DSA showed six CS-DAVFs in the six patients. TR-MRA demonstrated a hyperintensity area in the CS at the arterial phase in six patients. DSA revealed feeding arteries and a drainage vein in all CS-DAVFs. In contrast, the feeding arteries could not be identified with TR-MRA. The details regarding venous drainage could only be speculated upon with TR-MRA as it was only partly visible on the TR-MRA images. DSA after embolization showed no CS-DAVFs in any of the six patients. TR-MRA showed no hyperintensity areas in the CS at the arterial phase in any of the six patients, and with no coil artifacts. In summary, TR-MRA could detect and diagnose CS-DAVF. However, the detail regarding anatomical feeders and draining veins remains poorly visualized by TR-MRA. In this small number of cases, TR-MRA can be a useful screening tool to detect CS-DAVF and possibly also to confirm persistent obliteration following definitive treatment.