Angioarchitecture of Dural Arteriovenous Fistulas: Definition of Fistulous Points.

Because histopathological aspects of dural arteriovenous fistulas (DAVFs) are often lacking, there can be controversies regarding their angioarchitecture. Depending on various statements or DAVF types, the shunts can be situated directly on the sinuses, at the confluence of sinuses and cortical veins, in adjacent vascular structures surrounding the sinus, or, even, in the bone. Comprehensive knowledge of the intricate arteriovenous shunt anatomy is crucial for the secure and effective management of DAVFs. It has been confirmed that the dural arteries communicate with crack-like veins that connect ≥1 dural veins near the affected sinuses. In DAVFs, it is certain that ≥1 draining veins exist before draining into the venous sinus, in contrast to the commonly stated direct artery-to-sinus communication. Arteries branch and taper, and veins receive branches and thicken their lumens. We define fistulous points as the locations where the feeding arteries transition from thick to thin and the draining veins transition from thin to thick. We provide an image description based on superselective angiography.