In Vivo Characterization of Central Arterial Properties Using a Miniaturized pMUT Array Compared to a Clinical Transducer: A Feasibility Study Towards Wearable Pulse Wave Imaging.

Abstract

Piezoelectric micromachined ultrasound transducer (pMUT) technology shows promise for wearable ultrasound applications, although with limitations in acquisition performance compared to standard transducers. To translate Pulse Wave Imaging (PWI)-an ultrasound imaging technique that evaluates local arterial mechanics-into wearable applications, this study investigated the performance of integrating a miniaturized pMUT array into the PWI pipeline. Nine (n = 9) carotid arteries were scanned with a miniaturized pMUT array and an L7-4 linear transducer. Metrics like pulse wave velocity at end-diastole (PWV_ED) and end-systole (PWV_ES), compliance (C_ED, C_ES), and carotid pulse pressure (PP_C) were compared between imaging arrays. Lower SNR of axial wall velocities (SNR_vPWI) at end-diastole (L7-4: 47.9 ± 6.8 dB, pMUT: 43.3 ± 7.4 dB) and end-systole (L7-4: 45.4 ± 6.4 dB, pMUT: 38.1 ± 6.5 dB), and trends of higher coefficient of variation (CV) were found for PWI performed with the pMUT array compared to the L7-4. Bland-Altman analysis identified good agreement between the L7-4 and pMUT array for average PWV_ED (bias = -0.02 ± 0.42 m/s), PWV_ES (bias = -0.38 ± 1.3 m/s), C_ED (bias = 0.04 × 10^-9 ± 0.24 × 10^-9 m²/Pa), C_ES (bias = 0.11 × 10^-9 ± 0.38 × 10^-9 m²/Pa) and PP_C (bias = 1.06 ± 5.08 mmHg). The findings revealed comparable performance between the miniaturized pMUT array and L7-4 for PWI, highlighting the versatility of the PWI technique. This feasibility study illustrates the potential for translating PWI into wearable configurations, opening new avenues for cardiovascular health monitoring.