Objectives: To investigate the feasibility of one-stop examination of aortic pulse wave velocity (PWV) , aortic distensibility (AD), and brachial artery flow-mediated dilation (FMD) in healthy volunteers by means of 3.0-T high-resolution magnetic resonance imaging (MRI).
Methods: A total of 32 healthy volunteers (24-37 years old; mean age, 29 years) underwent repeated high-resolution MRI to assess aortic PWV, ascending aorta (AA) AD, proximal descending aorta (PDA) AD, distal descending aorta (DDA) AD, and FMD of the brachial artery with an interval of 1 to 2 hours. Pulse wave velocity was evaluated by 2-dimensional (2D) phase contrast velocity-encoded MRI with a 4.7- to 7.8-millisecond (ms) temporal resolution. Fiesta-cine MRI was used to assess AD and FMD with a 18.75- to 31.25-ms temporal resolution. The image quality of repeated scans was evaluated with 4-point scores, and the agreement between the 2 scans was tested with kappa analysis. The reproducibility of the results from repeated measurements for PWV, AA-AD, PDA-AD, DDA-AD, and FMD was assessed with intraclass correlation coefficient (ICC) analysis. The method of Bland-Altman plot was also used to assess the agreement between repeated measurements.
Results: Each examination including PWV, AD, and FMD were completed in approximately half an hour. The image quality between repeated scans showed good agreement (κ value, 0.776) with a mean score of 3.53 and 3.41, respectively. Reproducibility between repeated measurements was high for aortic PWV (4.33 ± 0.88 vs 4.36 ± 0.88 m/s; ICCPWV = 0.95; P < 0.01), AA-AD (8.60 ± 3.11 vs 8.59 ± 3.10 × 10−3 mm Hg−1; ICCAA-AD = 0.97; P < 0.01), PDA-AD (6.95 ± 2.44 vs 6.95 ± 2.42 × 10−3 mm Hg−1; ICCPDA-AD = 0.99; P < 0.01), DDA (10.54 ± 2.91 vs 10.55 ± 2.90 × 10−3mm Hg−1; ICCDDA-AD = 0.98, P < 0.01), and FMD (24.94 ± 12.55 vs 24.92 ± 12.38%; ICCFMD = 0.94, P < 0.01). Good agreement between repeated measurements was found for aortic PWV (confidence interval [CI], −0.55 to 0.50), AA-AD (CI, −0.11 to 0.12), PDA-AD (CI, −0.08 to 0.08), DDA-AD (CI, −0.23 to 0.21), and FMD (CI, −1.46 to 1.51).
Conclusion: Comprehensive assessment of aortic compliance and brachial endothelial function can be achieved in a single examination using 3.0-T high-resolution MRI with good reproducibility and within a reasonable amount of time.