Background and purpose: The spatial resolution of 3D time-of-flight MR angiography (TOF-MRA) can be improved within a reasonable examination time by combining 3T and sensitivity encoding technique. We evaluated the diagnostic performance of high-resolution 3D TOF-MRA at 3T in patients with suspected atherosclerotic steno-occlusive disease of the intracranial arteries.
Materials and methods: We assessed 160 arteries in 39 patients: 68 distal internal carotid arteries, 68 middle cerebral arteries, and 24 vertebrobasilar arteries. The measured voxel size of 3D TOF-MRA was 0.28 x 0.56 x 1.2 mm(3). Steno-occlusive disease was assessed independently by 2 observers using conventional angiography as the reference standard.
Results: According to observers 1 and 2, respectively, 3D TOF-MRA at 3T had a sensitivity of 78%/85% (21/27, 23/27), a specificity of 95%/95% (126/133, 127/133), a positive predictive value of 75%/79% (21/28, 23/29), and a negative predictive value of 95%/97% (126/132, 127/131), using a 50%-99% threshold of diameter stenosis. For detection of complete occlusion, according to observers 1 and 2, respectively, 3D TOF-MRA at 3T had a sensitivity of 100% (13/13), a specificity of 99% (145/147), a positive predictive value of 87% (13/15), and a negative predictive value of 100% (145/145). Interobserver agreement of 3D TOF-MRA was excellent (kappa = 0.81).
Conclusion: High-resolution 3D TOF-MRA with sensitivity encoding at 3T can be used as a reliable diagnostic tool for the detection of clinically significant steno-occlusive disease of major intracranial arteries.