2004 Volume 13 Issue 10 Pages 711-717
A 36-year-old woman complained of a sudden headache, right hemiparesis, and visual disturbances. A CT scan showed a subarachnoid hemorrhage and a round, high-density mass near the left crural cistern. The initial cerebral angiogram revealed a large aneurysm in the left P2-3 segment of the posterior cerebral artery (PCA). The patient was treated conservatively. A MRI, taken 11 days after the onset, showed a partially thrombosed large aneurysm. The second angiogram, taken one month after the onset, showed complete occlusion of the aneurysm without visualization of the left distal PCA. The third angiogram, taken two months after the onset, showed recanalization of the distal PCA, and 3D-CT angiogram at two and a half months after the onset showed reappearance of the neck of the aneurysm. To prevent the aneurysm from rerupturing, parent artery occlusion (PAO) of the aneurysm was performed using endovascular surgery. Both the aneurysm and the P2-3 segment of the left PCA were obliterated. However, since collateral circulation through the parietal branches of the middle cerebral artery filled the distal PCA, no severe complications appeared following PAO. The patient was discharged with slight right hemiparesis, but no visual disturbances. Only a few cases have been reported involving the spontaneous disappearance of aneurysms on cerebral angiograms. Even rarer are cases involving the reappearance of aneurysms. In the past, surgical clipping was indicated for the treatment of P2-3 segment aneurysms. Recently, however, PAO has been performed using endovascular techniques. It has been reported PAO using endovascular techniques is a relatively safe treatment for P2-3 segment aneurysms, because the rich collateral blood supply to the PCA provides good ischemic stress tolerance.
