A feasibility study of a PMUT-based wearable sensor for the automatic monitoring of carotid artery parameters

The measurement of hemodynamic and morphological parameters in carotid artery like the peak blood velocity, the wall distensibility, the blood volume flow, the pulsatility index, and others, is of high medical interest. These indexes are routinely acquired during ultrasound examinations of patients. Unfortunately, at present, there is no possibility of a mid- or long- term continuous monitoring of such parameters in a non-clinical environment, like it is, for example, for basic cardiac parameters acquired through an Holter monitor. A wearable ultrasound device capable of continuous and automatic monitoring of carotid parameters needs a suitable sensor and a method for the automatic localization of the vessel, which compensates for patient's movements. In this work we present a pilot study based on a 16-element Piezoelectric Micromachined Ultrasonic Transducers (PMUT) array. It is shown that the PMUT, connected to the ULA-OP research scanner, produced B-mode phased-images of a vessel phantom where the vessel position was automatically tracked. The vessel was correctly located with accuracy better than 1 mm in more than 90% of the images.