PROJECT SUMMARY/ABSTRACT Three-dimensional ultrasound imaging (3D-US) is an essential clinical tool for visualizing, navigating, and investigating patient anatomy and pathologies in real time in 3D. Owing to its moderate cost and lack of ionizing radiation, 3D-US plays an important role in many clinical applications for diagnosis and intervention. Despite the significant clinical value and potential, 3D-US is not a widely accessible and capable technology with its current implementations: existing 3D-US solutions are challenged by many limitations such as low imaging speed, low functionality, bulky devices that are inconvenient to use, and a high cost of designated equipment. For decades, there has been a long-standing quest for developing an accessible, functional, and user-friendly 3D-US technology. In this proposal, we will develop a new 3D-US solution (called FASTER) that uses a novel, fast-tilting microfabricated acoustic reflector to achieve high-speed and high-functionality 3D-US imaging. The acoustic reflector is water-immersible and enclosed in a clip-on device that is compact, lightweight, and low-cost. It can be easily attached to and removed from different types of ultrasound transducers to turn a conventional 2D ultrasound system into 3D. Unlike conventional 3D-US technologies (e.g., wobbler transducers and 2D matrix arrays), FASTER does not require the procurement of additional ultrasound transducers for different applications. Also, FASTER achieves a much higher imaging volume rate (up to 1000 Hz) than conventional 3D-US technologies. FASTER is compatible with most ultrasound systems on the market ranging from premium scanners to portable and handheld devices. In this proposal, we will conduct basic technology development research and carry out preliminary clinical studies to build a solid technical foundation for the FASTER 3D-US technology. In Aim 1 we will focus on developing the Phase-1 FASTER device that uses a double-axis reflector for extended range of imaging volume rate and field-of-view (FOV). We will also develop Phase-1 FASTER into a stand-alone device that does not need external equipment and communicates wirelessly with the ultrasound system. Aim 2 will focus on developing advanced imaging modes for FASTER, including 3D blood flow imaging (3D-BFI) and 3D shear wave elastography (3D-SWE). Pilot clinical studies will be conducted for both Aims 1 and 2 to facilitate the development and optimization of the FASTER device and imaging sequences. In Aim 3 we will conduct a clinical study to evaluate the performance of FASTER 3D-US in characterizing suspicious axillary lymph nodes (ALNs) for breast cancer patients undergoing clinically indicated biopsy of ALN. We will also evaluate the performance of FASTER in localizing clipped ALNs from patients undergoing neoadjuvant chemotherapy. The study aims will be carried out by a team of experts in ultrasound imaging, micro sensors and systems, medical device design, and breast cancer from the campuses of University of Illinois Urbana- Champaign, Texas A&M University, and Mayo Clinic.

PROJECT NARRATIVE Three-dimensional ultrasound imaging is an important clinical tool for disease diagnosis as well as providing guidance for interventional and surgical procedures. At present, existing three-dimensional ultrasound imaging technologies are not widely accessible, difficult to use, and do not provide sufficient imaging functionality to meet the clinical needs. To fill the gap, we propose to develop a new three-dimensional ultrasound imaging solution that is accessible, functional, user-friendly, low-cost, and compatible with most existing ultrasound imaging systems in the clinic.