[Angiographical frequency of unruptured incidental intracranial aneurysms]

We reviewed cerebral angiograms studied between May 1985 and December 1992 focusing on unruptured incidental intracranial aneurysms. In a total of 605 cases of cerebral angiograms except for patients with SAH, 43 patients (7.1%) were found to have unruptured aneurysms. In the 72 patients with headache, 11 patients (15.3%) were found to have unruptured aneurysms. This high frequency of unruptured aneurysms in headache patients is significant as a factor showing that headache may be due to unruptured aneurysms. The result of this observation is that as a screening study for headache patients, cerebral angiography may be required in spite of the invasive and high-risk method. But we think that MR angiography is, at present, a useful screening study only for detecting cerebral aneurysms with a diameter of over 5mm, and which are considered to need an operation.