Contrast-free MRA at 3.0 T for the detection of intracranial aneurysms

Objective: We prospectively investigated the diagnostic accuracy of contrast-free 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) with volume rendering (VR) at 3.0 T to detect intracranial aneurysms in a large cohort of patients.

Methods: We conducted a prospective clinical study including 411 patients with suspected aneurysms and other cerebral vascular diseases who were referred for contrast-free 3D-TOF-MRA at 3.0 T prior to digital subtraction angiography (DSA). 2D-DSA and VR-DSA were regarded as the gold standard. Forty-two patients were excluded. Accuracy, sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV) as measures to detect or rule out intracranial aneurysms were determined by patient-, aneurysm-, vessel-, and aneurysm size–based evaluations.

Results: In all 369 patients investigated, VR-DSA revealed 307 aneurysms in 246 patients (66.7%) and no aneurysm in 123 patients. The patient-based evaluation by VR 3D-TOF-MRA at 3.0 T yielded an accuracy of 97.6%, a sensitivity of 99.2%, specificity of 94.4%, PPV of 97.2%, and NPV of 98.3% in the detection of intracranial aneurysms. The aneurysm-based evaluation yielded an accuracy of 98.3%, sensitivity of 99.3%, specificity of 96.9%, PPV of 97.8%, and NPV of 99.1%. The vessel-based evaluation yielded accuracy of 98.8%, sensitivity of 99.2%, specificity of 98.5%, PPV of 97.5%, and NPV of 99.6%. The evaluation based on aneurysm sizes yielded similar results.

Conclusions: VR 3D-TOF-MRA at 3.0 T accurately identified the presence of intracranial aneurysms. High PPV and NPV indicated that VR 3D-TOF-MRA at 3.0 T may replace DSA as a contrast-free, noninvasive, and non-radiation-based modality for the diagnosis and screening of intracranial aneurysms.