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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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. SIGNIFICANCE: 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.