A Case of a Ruptured Aneurysm at the Supracallosal Portion (A4–A5) of the Bihemispheric Anterior Cerebral Artery Treated with Endovascular Surgery

OBJECTIVE: To report our experience on a rare case of a ruptured aneurysm at the supracallosal portion (A4–A5) of the bihemispheric anterior cerebral artery (ACA), an ACA anomaly, and present that endovascular surgery was a good treatment even for peripheral cerebral aneurysm. CASE PRESENTATION: A 53-year-old woman experienced a sudden onset of severe headache and vomiting. Plain CT scan revealed subarachnoid hemorrhage and hematoma in the supracallosal area. Cerebral angiography showed that the left pericallosal artery supplied blood to the bilateral parietal lobes through the bihemispheric artery. A saccular aneurysm was found at the supracallosal portion of the left bihemispheric ACA. Coil embolization of the cerebral aneurysm was performed completely. CONCLUSION: Several reports have demonstrated an aneurysm with bihemispheric ACA, all treated by neck clipping. In this case, endovascular treatment for intracranial peripheral cerebral aneurysms becomes possible, and treatment indications are said to expand.