Underwater Ultrasonic Imaging of Microbubbles for Real-time Control of Decompression Procedures Using Wearable CMUT Arrays

Decompression sickness remains a major risk for scuba divers unless they follow strict decompression staging. Mitigation protocols rely on probabilistic, population risk models to a particular dive profile, but do not account for individual diver physiology. A wearable system that is capable of quantifying bubble formation and growth during the dive could interface with dive computers for such an optimization of the decompression. Clearsens Inc. is a start-up company that aims to translate capacitive micromachined ultrasonic transducer (CMUT) technology for a wearable ultrasound imaging system while having the ability to implement both traditional (B-mode/Doppler) imaging and microbubble-specific imaging schemes developed in the context of clinical contrast-enhanced ultrasound (CEUS). In this project, we propose to leverage this technology for multiplexed imaging of the anatomy, venous gas emboli and possible <10 µm stationary (tissue) microbubbles. We will optimize ultrasound parameters and test prototype CMUT arrays for both flowing and stationary microbubble imaging in tissue-mimicking materials in collaboration with UNC/NCSU and evaluate CMUT sensitivity and bandwidth with respect to pressure up to 300 fsw with Duke. Finally, we will design a prototype wearable CMUT array, optimize array parameters, electronic interfacing, form factor, and prepare our evaluation plan for Phase II including human trials.