MR Angiography of Dural Arteriovenous Fistulas: Diagnosis and Follow-Up after Treatment Using a Time-Resolved 3D Contrast-Enhanced Technique

Preinterventional targeted MIP reconstructed sagittal image from an arterial phase of TR 3D MRA (A) shows a DAVF at the transverse/sigmoid sinus (short arrow) with strong early filling of the sinuses and feeding arterial branches from a prominent right occipital artery (long arrow). Small reflux into the proximal part of the vein of Labbé (arrowhead) is noted. The targeted MIP reconstructed image obtained from follow-up TR 3D MRA examination (B) after transvenous occlusion of the right transverse sinus clearly shows a residual fistula at the sigmoid sinus (short arrow) with downstaging of venous hypertension to anterograde sinus flow (type 1).

Sagittal targeted MIP reconstructed image obtained from an early arterial phase of TR 3D MRA shows a DAVF with strong and early filling of the torcular of Herophili, of the right transverse/sigmoid sinus (long arrow) and intense venous reflux into an enlarged superior vermian vein (short arrow) that follows the course of the tentorium in the midline. A large network of feeding branches from bilateral occipital arteries is observed (arrowheads).

TR 3D MRA is obtained before and after surgical exclusion of a high-grade DAVF (type 4) on a left medial tentorial sinus. The complete arteriovenous series of sagittal MIP-reconstructed images (A) shows early enhancement of dilated veins with a large venous varix (black arrow) on the left tentorium at early arterial inflow (top left). Consecutive filling of the straight sinus and the transverse sinuses from the fistula is noted at later arterial phase (top right, black arrowheads). Regular temporal enhancement of the superior sagittal sinus (white arrowheads) can be appreciated during venous phases (lower panel). Note that fistula occlusion is definitely demonstrated by the absence of early filling of tentorial veins and varix on the follow-up study after surgery (B). On 3D TOF MRA, however, the venous varix (white arrow) is still depicted with a high signal intensity imitating fistula flow (C).