Microscale Integrated Systems for Ultrasound Imaging and Sensing in Coronary Arteries

Abstract

Current intravascular ultrasound (IVUS) imaging systems only offer side-looking capabilities and cannot generate images of the volume in front of the catheter. An IVUS catheter that can provide forward-viewing volumetric ultrasound images would be an invaluable clinical tool for guiding interventions in coronary arteries for treatment of chronic total occlusions and for helping stent deployment. In this talk, we describe design, fabrication and testing of a forward-viewing IVUS system where all the main functionalities of transmitting and receiving ultrasonic waves in the 10-20MHz range with more than 100 array elements are integrated in a 1.5mm diameter donut shaped silicon chip. The imaging system is based on monolithic integration of Capacitive Micromachined Ultrasonic Transducers (CMUTs) and custom designed CMOS electronic in silicon. This approach requires only about a dozen external electrical connections enabling a highly flexible catheter. We discuss the design and fabrication process and present initial imaging results obtained by the system on relevant biological samples. Future capabilities that can be integrated to this platform for dual-mode imaging and therapeutic devices are also discussed.