Epidemiological features and diagnostic evaluation of intracranial aneurysms.

Female gender and cigarette smoking appear to be risk factors for the development of multiple intracranial aneurysms. An acquired nature is likely in this form. The mechanism of aneurysm formation in patients with sickle cell anemia is apparently different. These patients also present multiple aneurysms that show propensity for vertebrobasilar territory and appear at a younger age. Familial cerebral aneurysms are diagnosed once heritable connective tissue disorders have been excluded. The age of patients tends to be lower and the size of aneurysm to be smaller at the time of rupture in the familial form. These aneurysms are less frequently found in the anterior communicating artery than the sporadic aneurysms. A high incidence of asymptomatic familial aneurysms was detected in people with family histories of intracranial aneurysms studied by means of magnetic resonance angiography. Furthermore, familial aneurysms are more likely to rupture in families having members with aneurysmal subarachnoid hemorrhage (SAH) than in those without. The results of an interesting study using color "power" transcranial Doppler ultrasound in patients with aneurysmal SAH suggest that as the intracranial pressure diminished, the size of the aneurysm increased, and there was relatively little change between maximum and minimum dimensions during the cardiac cycle, i.e., the pulsatility is reduced. The use of postoperative angiography after clipping is a matter of debate. The indication more widely accepted is in large aneurysms with a wide neck, in which incomplete clipping can be suspected. Taking into account the current low risk of angiography in centers of excellence, its routine use may be recommended. Aneurysm remnants, vessel occlusion, vasospasm, and newly identified aneurysms are the main findings that were reported.