ABSTRACT
We report here on a rare case of a ruptured basilar tip aneurysm that was successfully treated with coil embolization in the bilateral cervical internal carotid artery (ICA) occlusions with abnormal vascular networks from the posterior circulation. A 43-year old man with a familial history of moyamoya disease presented with subarachnoid hemorrhage. Digital subtraction angiography demonstrated complete occlusion of the bilateral ICAs at the proximal portion and a ruptured aneurysm at the basilar artery bifurcation. Each meningeal artery supplied the anterior cranial base, but most of both hemispheres were supplied with blood from the basilar artery and the posterior cerebral arteries through a large number of collateral vessels to the ICA bifurcation as well as the anterior cerebral and middle cerebral arteries. The perfusion computed tomography (CT) scans with acetazolamide (ACZ) injection revealed no reduction of cerebral blood flow and normal cerebrovascular reactivity to ACZ. An abdominal CT aortogram showed no other extracranial vessel abnormalities. A ruptured basilar tip aneurysm was successfully treated with coil embolization without complications. Endovascular embolization may be a good treatment option with excellent safety for a ruptured basilar tip aneurysm that accompanies proximal ICA occlusion with vulnerable collateral flow.