Can noninvasive imaging accurately depict intracranial aneurysms? A systematic review

PURPOSE: To perform a systematic review to determine the accuracy of comput ed tomographic (CT) angiography, magnetic resonance (MR) angiography, and t ranscranial Doppler ultrasonography (US) in depicting intracranial aneurysm s. MATERIALS AND METHODS: A 1988-1998 literature search for studies with 10 or more subjects in which noninvasive imaging was compared with angiography w as undertaken. Studies meeting initial criteria were evaluated by using int rinsically weighted standardized assessment to determine suitability for in clusion. Studies scoring greater than 50% were included. RESULTS: Of 103 studies that met initial criteria, 38 scored greater than 5 0%. CT angiography and MR angiography had accuracies per aneurysm of 89% (9 5% CI: 87%, 91%) and 90% (95% CI: 87%, 92%), respectively. For US, data wer e scanty and accuracy was lower, although the Cls overlapped those of CT an giography and MR angiography. Sensitivity was greater for detection of-aneu rysms larger than 3 mm than for detection of aneurysms 3 mm or smaller-for CT angiography, 96% (95% CI: 94%, 98%) versus 61% (95% CI: 51%, 70%), and f or MR angiography, 94% (95% CI: 90%, 97%) versus 38% (95% CI: 25%, 53%). Di agnostic accuracy was similar for anterior and posterior circulation aneury sms. CONCLUSION: CT angiography and MR angiography depicted aneurysms with an ac curacy of about 90%. Most studies were performed in populations with high a neurysm prevalence, which may have introduced bias toward noninvasive exami nations.