Estimation of aortic compliance using magnetic resonance pulse wave velocity measurement

A method for compliance estimation employing magnetic resonance pulse wave velocity measurement is presented. Time-resolved flow waves are recorded at several positions along the vessel using a phase contrast sequence, and pu lse wave velocity is calculated from the delay of the wave onsets. Using re trospective cardiac gating in combination with an optically decoupled elect rocardiogram acquisition, a high temporal resolution of 3 ms can be achieve d. A phantom set-up for the simulation of pulsatile flow in a compliant ves sel is described. In the phantom, relative errors of pulse wave velocity es timation were found to be about 15%, whereas in a volunteer, larger errors were found that might be caused by vessel branches. Results of pulse wave v elocity estimation agree with direct aortic distension measurements which r ely on a peripheral estimate of aortic pressure and are therefore less accu rate. Studies in 12 volunteers show values of pulse wave velocity consisten t with the literature; in particular the well-known increase in pulse wave velocity with age was observed. Preliminary results show that the method ca n be applied to aortic aneurysms.