Native high-resolution 3D SSFP MR angiography for assessing the thoracic aorta

Methods Seventy-six prospective patients with known or suspicion of thoracic aortic disease underwent MRA at 1.5T using i) native 3D SSFP MRA with ECG and navigator gating and high isotropic spatial resolution (1.3 × 1.3 × 1.3 mm 3) and ii) conventional contrast-enhanced ECG-gated gradient echo 3D MRA (1.3 × 0.8 × 1.8 mm 3). Datasets were compared at 9 aortic levels regarding image quality (score 0-3: 0 = poor, 3 = excellent) and aortic diameters, as well as observer dependency and final diagnosis. Results Native 3D-MRA was acquired successfully in 70/76 subjects (mean acquisition time 8.6 ± 2.7 min), while irregular breathing excluded 6/76 subjects. Aortic diameters agreed close between both methods at all aortic levels (r = 0.99; bias ± SD -0.12 ± 1.2 mm) with low intraand inter-observer dependency (intraclass correlation coefficient 0.99). Native MRA studies resulted in the same final diagnosis as the contrast-enhanced MRA. Mean image quality score was superior with native compared to contrast-enhanced MRA (2.4 ± 0.6 vs. 1.6 ± 0.5; p < 0.001). The Figure provides a set of examples acquired with both techniques (left: native, right: contrast-enhanced).