Assessment and reproducibility of aortic atherosclerosis magnetic resonance imaging: Impact of 3-tesla field strength and parallel imaging

Objectives: To investigate image quality and interstudy reproducibility of aortic atherosclerosis imaging at 1.5 T, and to explore the impact of parallel imaging techniques at 3 T. Materials and methods: Institutional review board approval and informed consent were obtained. Thirty-two subjects (20 normal, 12 patients with impaired cardiac function) underwent 4 black-blood T2-weighted imaging studies of the abdominal aorta: 2 conventional studies at 1.5 T, a conventional study at 3 T, and an accelerated 3-T study with parallel imaging (SENSE). Contrast-to-noise ratio and image quality score (1ĝ€"5 scale, 5 ≤ highest quality) were determined for each study. Studies were analyzed for mean wall thickness and area plaque burden as endpoints for aortic atherosclerosis. Bland-Altman analyses were performed to determine interstudy reproducibility between imaging methods. Wilcoxon signed-rank tests were used to identify significant differences between methods (P < 0.05). Results: Image quality scores were comparable between 1.5 T and 3 T with SENSE (4.0 ± 0.6 vs. 4.2 ± 0.6, P ≤ 0.21). Bland-Altman reproducibility for mean wall thickness was ĝ̂'0.03 mm ± 0.15 (1.5 T vs. 1.5 T), 0.01 mm ± 0.17 (1.5 T vs. 3 T without SENSE), and ĝ̂'0.01 mm ± 0.18 (1.5 T vs. 3 T with SENSE), P ≤ 0.83. Detection of the presence or absence of plaque was comparable. Bland-Altman reproducibility for area plaque burden was ĝ̂'0.02% ± 0.32% (1.5 T vs. 1.5 T), 0.06% ± 0.41% (1.5 T vs. 3 T without SENSE), and 0.11% ± 0.33% (1.5 T vs. 3 T with SENSE), P ≤ 0.41. Conclusion: Black-blood MR imaging of aortic atherosclerosis is very reproducible. Parallel imaging at 3 T permits shorter scan time compared with conventional 1.5-T imaging with comparable measures of atherosclerosis extent.