Reproducibility of pulse wave velocity measurements with phase contrast magnetic resonance and applanation tonometry

Increased aortic pulse wave velocity (PWV) results from loss of arterial compliance and is associated with unfavorable outcomes. Applanation tonometry (AT) is the most frequently applied method to assess PWV and deduce aortic compliance. The goal of this study was to compare the reproducibility of PWV measurements obtained with: (1) cross-correlation analysis of phase contrast magnetic resonance (PCMR) velocity data, and (2) applanation tonometry (AT). PWV was measured twice with each modality in 13 normal young volunteers (controls) and 9 older patients who had undergone a CT exam to evaluate coronary artery calcium. The coefficient of variation (CoV) between measurements was computed for each modality. There was no significant difference in PWV values obtained with AT and PCMR in controls or patients. The inter-scan reproducibility of PCMR was superior to AT in the controls (CoV: 3.4 +/- A 2.3% vs. 6.3 +/- A 4.0%, P = 0.03) but not in the older patients (7.4 +/- A 8.0% vs. 9.9 +/- A 9.6%, P = 0.32). PWV values were higher in patients than controls (5.6 +/- A 1.2 vs. 9.7 +/- A 2.8, P = 0.002). PCMR and AT yielded similar values for PWV in patients and volunteers. PCMR showed a superior reproducibility in young subjects but not in older patients.