Fig. 5: Human carotid artery ultrasound images and monitoring of blood pressure obtained with prototype disposable ultrasound patches.

a Photograph of attached disposable snCMUT patches onto both sides of the human neck for real-time ultrasound imaging and blood pressure monitoring of human carotid arteries. The B-mode images at the human neck surface aligned with vertical cross-sections of the common carotid artery (CCA) on the right (b) and left (c) side of the neck. The enhanced transmission efficiency provided clear ultrasound images, enabling the distinction of not only the CCA but also the internal jugular vein (JV) and sternocleidomastoid muscle (SCM). d The B-mode image of left neck side transverse CCA for monitoring carotid artery pulsations from detecting wall. The applied DC bias voltage was 30 V supplemented by 24.5 V_PP of 4.25 MHz AC wave for ultrasound imaging via disposable snCMUT patches. e M-mode image of the pulsation pattern of CCA walls. f The waveforms of blood pressure derived from carotid vessel diameters of the M-mode image (e) as a function of time. Physiological parameters from the arterial pulse waveforms, including the heart rate and blood pressure, were derived. g Systolic blood pressure on the left and right side of the neck of 9 healthy volunteers simultaneously monitored by two disposable snCMUT patches. Data are presented as means ± standard deviation (n = 5 independent experiments).