A Novel and Low Cost Acoustic based Probe for Local Pulse Wave Velocity Estimation - Experimental Characterization and in-Vivo Feasibility

The use of local pulse wave velocity (PWV) as an independent risk factor for cardiovascular events and as a marker of atherosclerosis has been gained clinical relevance over the years. A novel acoustic double headed probe for non-invasive measurement of the local PWV is presented in this paper. The PWV is assessed in one single location and involves the determination of time delay between the signals acquired simultaneously by two acoustic sensors, placed ≈11 mm apart. Several tests were performed in special purposes test bench systems in order to characterize the acoustic probe (AP) regarding the existence of crosstalk between the transducers, repeatability, waveform analysis and also its time resolution. Results demonstrate the effectiveness of the AP in acquiring repeatedly the same waveform, with the possibility to measure higher PWV (14 m/s), with a relative error less than 5%, when using two uncoupled APs. In-vivo acquisitions were also carried out with the AP in the carotid artery of 17 healthy volunteers with the intention of local PWV and other hemodynamic parameters estimation, such as left ventricular ejection time (LVET). For the total of subjects’ sample, the obtained mean carotid PWV was 2.96±1.08 m/s and the LVET mean value was 288.59±21.42 ms.