Differential diagnosis of ruptured intracranial aneurysms

Although magnetic resonance imaging (MRI) is now often used to demonstrate intracranial lesions, subarachnoid hemorrhage (SAH) due to a ruptured cerebral aneurysm is almost always diagnosed by computed tomography (CT). CT is still the first diagnostic tool for SAH. However, it is not often easy to dertermine the site of the ruptured cerebral aneurysm. We investigated the site of rupture of aneurysms using 127 consecutive CT films of ruptured cerebral aneurysms. The grade of SAH was classified from 0 to 4 according to the regional density of the cisterns, and the presence of ICH and IVH was expressed by 1 and their absence by 0. We calculated the mean values and standard deviations of SAH grades and ICH/IVH presence or absence. Curves were plotted for each ruptured cerebral aneurysm. In 82 of all cases we diagnosed the position of the ruptured cerebral aneurysm correctly by using the patterns of these curves. (author)