FIG 1. A–K, 34-year old woman with severe headache and a right third cranial nerve palsy.

A, Brain CT scan shows focal hemorrhage surrounding the aneurysm (arrow) in the right prepontine cistern.

B and C, Cerebral arteriogram during left vertebral artery injection shows a fusiform aneurysm (arrows) arising from the proximal right PCA. Note that there is no filling during right carotid artery injection.

D and E, After clipping, there is no filling of the aneurysm from either the vertebral or carotid injections. The surgical clip is denoted by straight arrows. Note continued opacification of the distal right PCA (curved arrow, E), presumably supplied by the posterior communicating artery. Continued