Fig 1. Digital subtraction angiography (lateral view) of right (A) and left (B) internal carotid arteries shows occlusion of both vessels beyond the origin of the ophthalmic artery. Hypertrophy of perforator arteries likely to provide collateral flow (more prominent on the left side) is noted. Left vertebral artery injection: anteroposterior (C) and lateral (D) views show hypertrophied posterior communicating arteries supplying the anterior circulation. Aneurysms are noted in the left AICA (arrow), the left PICA (arrowhead), and the left posterior cerebral artery (double arrow). The small posterior cerebral artery aneurysm was better profiled in 3D angiograms (not shown).