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.

Objective: 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.

Methods: 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 (PWVED) and end-systole (PWVES), compliance (CED, CES), and carotid pulse pressure (PPC) were compared between imaging arrays.

Results: Lower SNR of axial wall velocities (SNRvPWI) 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 PWVED (bias = -0.02 ± 0.42 m/s), PWVES (bias = -0.38 ± 1.3 m/s), CED (bias = 0.04 x 10-9 ± 0.24 x 10-9 m2/Pa), CES (bias = 0.11 x 10-9 ± 0.38 x 10-9 m2/Pa) and PPC (bias = 1.06 ± 5.08 mmHg).

Conclusion: The findings revealed comparable performance between the miniaturized pMUT array and L7-4 for PWI, highlighting the versatility of the PWI technique.

Significance: This feasibility study illustrates the potential for translating PWI into wearable configurations, opening new avenues for cardiovascular health monitoring.