Alignment-Free, Non-Invasive Blood Vessel Monitoring by Piezoelectric Micromachined Ultrasonic Transducers

This work presents an alignment-free blood vessel monitoring microsystem based on a piezoelectric micromachined ultrasonic transducer (pMUT) array using a beam steering scheme. Compared with the literature, three key achievements include: (1) quantifications for the impact of misalignments during the ultrasound detection of a brachial artery; (2) a beam steering strategy without manual alignment to expand the field of view; (3) a new technique based on the fast Fourier transform (FFT) phase shift to measure relative location changes of the anterior and posterior artery wall. Validations on the brachial artery of a volunteer show the successful extraction of the artery diameter with detailed dynamic features. As such, this work advances the field of non-invasive cardiovascular monitoring using pMUT.