Laser-micromachined, dual-resonant (17/33 MHz) ultrasound transducer with single electrical connection for forward-viewing guidance of a submm, robotically-steerable guidewire

Abstract

More than 200 million people have peripheral artery disease globally. Minimally-invasive revascularization procedures can relieve pain, improve mobility, and salvage limbs. To improve navigation in these procedures, a transducer operating at two frequencies requiring only a single cable was developed to provide forward-viewing imaging with high resolution close to the transducer and high penetration farther from the transducer for planning the trajectory of a submillimeter, robotically-steerable guidewire. For the developed prototypes, center frequencies for the transducers were approximately 17/34 (side-by-side design) and 17/33 MHz (concentric design). When imaging a 0.2-mm wire target at a depth of 5 mm, measured SNR values were >20 dB for each frequency band. Images formed of speckle-producing phantoms showed high penetration with the low-frequency band and high spatial resolution with the high-frequency band. Additionally, 3D reconstructions of a porcine artery demonstrate the ability to image tissue with high resolution and penetration. Simultaneous dual-band imaging could improve the ability of the interventionalist to navigate during difficult cases.