The Use of Ultrasound Imaging in Continuous Blood Vessel Area and Velocity Data Acquisition for Determining the Local Pulse Wave Velocity

Pulse wave velocity (PWV) is a useful biomarker in the monitoring and risk stratification of various cardiovascular diseases including hypertension. The current gold standard for non-invasive measurement is carotid-femoral PWV (cfPWV) measurement via direct tonometry. However, cfPWV provides only a global PWV measure, which emphasises the need for an alternative capable of local PWV assessment. There are several alternatives for local PWV measurement proposed in the literature and one promising alternative is ultrasound, which offers good penetration depth, accessibility, and a relatively low cost, making it well-suited for non-invasive, real-time acquisition of haemodynamic parameters for PWV estimation. This paper aims to evaluate the different approaches for ultrasound-based acquisition while considering technical and physiological constraints to optimise the accuracy, reliability, and reproducibility of the parameters collected for estimation. In particular, this paper focuses on the flow-area (QA) and lnDiameter-velocity (lnDU) methods, which require local area and velocity data for PWV estimation. Accordingly, this paper discusses the use of ultrasound imaging in vessel data acquisition, highlights various challenges and considerations to be managed during acquisition and processing, outlines the different ultrasound-based imaging modalities for acquiring area and velocity data, and compares the simultaneous and non-simultaneous acquisition of data for PWV estimation.