Continuous Monitoring of Carotid Artery Flow Volume Using a Wearable T-Shaped Ultrasound Patch.

Abstract

We present a novel wearable T-shaped ultrasound (WTSUS) patch for simultaneous short-axis and long-axis imaging monitoring of carotid artery in situ within the same cardiac cycle to measure the carotid blood flow volume. WTSUS patch consists of two same ultrathin ultrasound transducer arrays with a center frequency of 8.5 MHz. The B-mode imaging provides real-time measurement of the cross-section area of the carotid artery, while Doppler imaging captures velocity time integral. WTSUS patch exhibits a total thickness of 1.3 mm and a wide -6 dB bandwidth of 65%. The axial and lateral resolutions at a depth of 20 mm were 0.37 mm and 0.45 mm, respectively. In vitro flow volume experiments showed that the maximum measurement deviation using WTSUS patch was 6.3%. In vivo imaging of the human common carotid artery exhibited good agreement with a commercial ultrasound system, demonstrating the reliability of WTSUS-based wearable ultrasound system. This study exhibits a wearable ultrasound imaging patch with a reliable continuous monitoring of the carotid blood flow volume that is also comfortable and easy to wear. This work can provide a novel and reliable solution for noninvasive cardiac output estimation, with significant potential for applications in critical care and continuous monitoring of dynamic blood flow volume.