Intracranial aneurysms: MR angiographic screening in 400 asymptomatic individuals with increased familial risk.

PURPOSE: To evaluate the accuracy and limitations of magnetic resonance (MR) angiographic screening for incidental intracranial aneurysms (IAs) in healthy individuals with a family history of IA. MATERIALS AND METHODS: Four hundred asymptomatic individuals in 68 families with a history of aneurysmal subarachnoid hemorrhage underwent MR angiography. Six families also had a history of polycystic kidney disease. A multislab, three-dimensional, time-of-flight sequence was used. Conventional angiography was performed to confirm positive MR angiographic findings. RESULTS: IAs were detected with MR angiography in 37 individuals, 32 of whom underwent conventional angiography. Intraobserver consistency was excellent (kappa = 0.96), and interobserver reproducibility was good to excellent (kappa = 0.59-0.82). Both techniques showed similar results in the evaluation of size, localization, and orientation of aneurysms and visibility of the aneurysm neck. CONCLUSION: MR angiography is an accurate and feasible method of noninvasive screening for IAs in individuals at high risk. Conventional angiography is still necessary before operative treatment.