Feasibility of Wearable and At-Home Applications of Pulse Wave Imaging: Evaluation of Central Arterial Mechanics Using a Rigid PMUT Array in vivo

Advancements in piezoelectric micromachined ultrasound transducers (PMUTs) has allowed for the development of vascular ultrasound applications in wearable and at-home settings. Pulse wave imaging (PWI) is an ultrasound-elasticity technique that can estimate local pulse wave velocity at end-diastole (PWVED). To move towards wearable and at-home applications of PWI, the objective of this study was to compare the performance of a PMUT array against an L7-4 for PWI in (n=2) healthy subjects. The B-modes produced from the PMUT array had increased presence of noise and artifacts compared to the L7-4. SNRvPWI was found to be higher in the L7-4 acquisitions (47.5 ± 6.98 dB) compared to the PMUT array (35.66 ± 8.02 dB). However, there was still good agreement for PWVED between the L7-4 and PMUT array, with a mean absolute difference of 0.18 ± 0.07 m/s when averaging all PWVED estimates per carotid artery. Additionally, by using 10% (13) of lateral positions for the L7-4 and 30% (20) for the PMUT array, it was possible to estimate PWVED within 5% error compared to using all lateral positions (L7-4: 3.44 ± 1.06%, PMUT array: 3.57 ± 0.99%). This work showcases the potential for adapting PWI into wearable and at-home monitoring applications with a PMUT array.