Improved Aortic Pulse Wave Velocity Assessment From Multislice Two-Directional In-Plane Velocity-Encoded Magnetic Resonance Imaging

Purpose: To evaluate the accuracy and reproducibility of aortic pulse wave velocity (PWV) assessment by in-plane velocity-encoded magnetic resonance imaging (MRI). Materials and Methods: In 14 patients selected for cardiac catheterization on suspicion of coronary artery disease and 15 healthy volunteers, PWV was assessed with multislice two-directional in-plane velocity-encoded MRI (PWVi.p.) and compared with conventionally assessed PWV from multisite one-directional through-plane velocity-encoded MRI (PWVt.p.). In patients, PWV was also obtained from intraarterially acquired pressure-time curves (PWVpressure), which is considered the gold standard reference method. In volunteers, PWVi.p. and PWVt.p. were obtained in duplicate in the same examination to test reproducibility. Results: In patients, PWVi.p. showed stronger correlation and similar variation with PWVpressure than PWVt.p.). (Pearson correlation r = 0.75 vs. r = 0.58, and coefficient of variation [COV] = 10% vs. COV = 12%, respectively). In volunteers, repeated PWVi.p. assessment showed stronger correlation and less variation than repeated PWVt.p. (proximal aorta: r = 0.97 and COV = 10% vs. r = 0.69 and COV = 17%; distal aorta: r = 0.94 and COV = 12% vs. r = 0.90 and COV = 16%; total aorta: r = 0.97 and COV = 7% vs. r = 0.90 and COV = 13%). Conclusion: PWVi.p. is an improvement over conventional PWVt.p. by showing higher agreement as compared to the gold standard (PWVpressure) and higher reproducibility for repeated MRI assessment.