Accurate Diagnosis of Small Cerebral Aneurysms ≤5 mm in Diameter with 3.0-T MR Angiography

Abstract

To evaluate the diagnostic accuracy of three-dimensional (3D) time-of-flight (TOF) magnetic resonance (MR) angiography at 3.0 T in the detection of small cerebral aneurysms. The institutional review board approved the study protocol, and patients or qualifying family members provided informed consent. A total of 403 consecutive patients undergoing 3D TOF MR angiography and digital subtraction angiography (DSA) were prospectively enrolled. Small aneurysms were those 5 mm in diameter or smaller. DSA served as the reference standard. Three observers were blinded to clinical and DSA results, and they independently analyzed all 3D TOF MR angiographic data sets. Interobserver agreement was expressed in terms of Cohen κ value for categorical variables. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 3D TOF MR angiography in the detection of cerebral aneurysms were determined by using patient-, aneurysm-, and location-based evaluations. Of 403 patients, 273 aneurysms were detected with DSA in 230 patients. Patient-based evaluation with 3D TOF MR angiography at 3.0 T yielded an accuracy of 96%-97%, a sensitivity of 98.2%-98.7%, a specificity of 93.2% -94.8%, a PPV of 94.9%-96.2%, and an NPV of 97.6%-98.2% in the detection of cerebral aneurysms. Aneurysm-based evaluation yielded an accuracy of 96.4%-97.3%, a sensitivity of 98.5%-98.9%, a specificity of 93.2%-94.9%, a PPV of 95.7%-96.8%, and an NPV of 97.6%-98.2%. Aneurysm-location evaluations yielded similar results. Three-dimensional TOF MR angiography is a noninvasive method that shows promising diagnostic accuracy in the detection of small cerebral aneurysms.