5.4 The Repeatability and Validity of Pulse Wave Velocity Measured Using Phase Contrast Magnetic Resonance Imaging

Abstract

Background

Aortic pulse wave velocity (PWV) is an independent predictor of cardiovascular risk. Phase contrast magnetic resonance imaging (PCMRI) is a recent technique that allows PWV to be measured along the entire aorta (aPWV_MRI), as well as in regions of interest. The aim of this study was to test the repeatability of PWV assessed by MRI, and to validate this against carotid-femoral PWV using the Vicorder device (PWV_Vicorder) measured simultaneously to aPWV_MRI.

Methods:

147 subjects aged 18–85 years were recruited from the ACCT and ENIGMA Studies. All subjects were free of cardiovascular disease and medication. A PCMRI sequence (1.5T scanner, GE) was performed at two sites (1cm above the aortic valve, and 3cm above the aortic bifurcation) to determine aPWV_MRI. Brachial supine blood pressure and PWV_Vicorder were measured in the scanner simultaneous to image acquisition. Repeatability of PWV_MRI was assessed across 2 visits, in a subset of 10 subjects.

Results:

PWV_MRI showed good repeatability (mean difference = −0.4±2.1m/s). There was a strong correlation between aPWV_MRI and PWV_Vicorder (R=0.64, P<0.001), although, overall, aPWV_MRI was significantly lower than PWV_Vicorder (5.7±1.8vs. 7.1±1.4m/s, P<0.001).

Conclusions:

Measurements of PWV using PCMRI are reproducible and correlate with simultaneously measured carotid-femoral PWV.