A Wearable Ultrasound Sensor for the Simultaneous Assessment of Hemodynamics and Blood Pressure

Cardiovascular disease remains a major global health burden, and monitoring vascular information is crucial for the management of cardiovascular disease in daily life. However, existing wearable technologies suffer from limitations such as poor signal quality, limited sensing modalities, and low accuracy. Here, we propose a wearable ultrasonic array patch system comprising 64 elements to overcome the above difficulties and be used for tracking blood dynamics and blood pressure fluctuations. Guided by finite-element piezoelectric simulations, the size of the ultrasonic array was designed. Additionally, the patch utilizes a hydrogel material to ensure proper coupling with the skin. Testing revealed that the patch achieves a -6 dB bandwidth of 71% and a peak-to-peak received voltage of 0.22 V. The patch achieves a high spatial resolution of 0.96 mm × 0.60 mm at a detection depth of 15 mm. The system employs two key approaches to acquire physiological information. The first is a multimodal acquisition scheme capable of simultaneously capturing relative blood pressure trends and hemodynamic characteristics. The second is an angle-dependent reduced vector Doppler framework that utilizes multi-angle beams to calculate blood flow vectors. This work builds on existing wearable ultrasound devices and establishes a platform for the continuous assessment and monitoring of vascular hemodynamics.