Operations on aneurysms of the anterior communicating artery not visualized by cerebral angiography--report of four cases.

Four cases of anterior communicating aneurysms are reported with clinical presentations of recurrent intracranial hemorrhage undisclosed in their cerebral angiography. Operative exploration revealed anterior communicating aneurysms in these patients. It is thought possible that these patients harbored aneurysms which failed to exhibit on angiograms due to temporary thrombosis or development of abnormal cerebral vessels. CT scanning was important for diagnosis of these patients.