Purpose: To assess the clinical utility and accuracy of contrast material-enhanced dynamic three-dimensional (3D) T1-weighted magnetic resonance (MR) angiography in the detection of unruptured intracranial aneurysms.
Materials and methods: A prospective blinded comparison of 3D contrast-enhanced T1-weighted MR angiography with 3D inflow magnetization transfer and tilted optimized nonsaturating excitation (MT TONE) imaging, phase-contrast MR angiography, and conventional digital subtraction angiography (DSA) was performed in 32 consecutive patients. The first dynamic 3D contrast-enhanced T1-weighted acquisition was individually timed after injection of a bolus of gadolinium-based contrast agent to obtain an arterial phase image followed by two sequential venous phase images (three 18-second acquisitions). Two readers independently interpreted and graded the MR images for diagnostic confidence and depiction of aneurysms and subsequently compared them with DSA images.
Results: Three-dimensional contrast-enhanced T1-weighted MR angiograms depicted all 23 aneurysms detected in 17 patients at DSA (mean size, 6 mm; range, 2-21 mm) with one false-positive result by one reader (sensitivity, 100%; specificity, 94%). MT TONE and phase-contrast images failed to depict one and seven aneurysms, respectively (MT TONE sensitivity of 96% and specificity of 100%, phase-contrast sensitivity of 70% and specificity of 100%). Aneurysm depiction at 3D contrast-enhanced T1-weighted MR angiography was significantly better than that at MT TONE imaging (P <.012), and that with both was significantly superior to that of phase-contrast imaging (P <. 001). Differences in diagnostic confidence in the presence of an aneurysm were not significant between 3D contrast-enhanced T1-weighted and MT TONE imaging (P =.076).
Conclusion: Dynamic 3D contrast-enhanced T1-weighted MR angiography is a fast, efficient, and minimally invasive imaging method with which to diagnose intracranial aneurysms.