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 (PWV(i.p.)) and compared with conventionally assessed PWV from multisite one-directional through-plane velocity-encoded MRI (PWV(t.p.)). In patients, PWV was also obtained from intraarterially acquired pressure-time curves (PWV(pressure)), which is considered the gold standard reference method. In volunteers, PWV(i.p.) and PWV(t.p.) were obtained in duplicate in the same examination to test reproducibility.
RESULTS: In patients, PWV(i.p.) showed stronger correlation and similar variation with PWV(pressure) than PWV(t.p.) (Pearson correlation r = 0.75 vs. r = 0.58, and coefficient of variation [COV] = 10% vs. COV = 12%, respectively). In volunteers, repeated PWV(i.p.) assessment showed stronger correlation and less variation than repeated PWV(t.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: PWV(i.p.) is an improvement over conventional PWV(t.p.) by showing higher agreement as compared to the gold standard (PWV(pressure)) and higher reproducibility for repeated MRI assessment.