Fig 4.

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).