During the past decade, MRA, as a preferred accuracy modality for noninvasive intracranial vascular imaging at most centers, is playing an increasing role in the evaluation of patients suspected of having intracranial aneurysms. In recurrent study, we have tested that MRA at 3T has excellent sensitivity, accuracy, and correlation with DSA and is comparable to catheter cerebral angiography for the evaluation of patients with intracranial aneurysms (Stroke, in press). Therefore, we examined trends in intracranial aneurysm prevalence with the use of MRA at 3.0T to determine the true prevalence of cerebral intracranial aneurysms in the general middle-aged or elder population.