Fig 2.

A, Axial 3-mm-slab MIP from CTA in patient 3 with a right sigmoid DAVF exhibits a markedly enlarged R occipital artery at the C1–2 level (large white arrow). There are also abnormally prominent small vessels surrounding the right vertebral and distal internal carotid arteries (white arrowheads). B, DSA, arterial phase, right external carotid injection in a lateral projection, demonstrates a markedly enlarged occipital artery (long black arrows), the angiographic correlate of the CTA in A. Transosseous branches (black arrowheads) of the occipital artery and middle meningeal artery feeders (white arrowheads) contribute to this sigmoid dural fistula. C, Axial 3-mm-slab MIP. The right sigmoid sinus is markedly enlarged and has a very irregular medial margin (arrow), an example of the shaggy sinus sign (patient 2). D, Another shaggy sinus sign involving the right transverse sinus. (The shaggy sinus only occurred in patients and was not seen in the control population.) E, DSA, right external carotid injection in a lateral projection, shows a typical DAVF with abnormal early opacification of the proximal occluded sigmoid sinus with retrograde flow through the transverse sinus to the contralateral dural sinuses. Arterial feeders arise from the middle meningeal artery (white arrowhead) and posterior auricular artery (black arrow) in patient 2. Angiographically, this sinus also appears shaggy (black arrowheads).