抄録
It is rare to encounter subarachnoid hemorrhage (SAH) whose origin cannot be detected by cerebral angiography. Occasionally, the detection is prevented by initial disappearance of the cerebral aneurysm as soon as it has ruptured. The collapse of cerebral aneurysm might be caused by perianeurysmal hematoma and brain, the thrombosed aneurysm, early cerebral vasospasm, and unknown etiology. We encountered a ruptured aneurysm that was finally detected by cerebral angiography in the third examination. The aneurysm was partially thrombosed pathologically. We speculate on the management of SAH whose origin cannot be detected by cerebral angiography.
