A Dual-Mode Miniature Ultrasound Probe for Combined Intravascular Ultrasound Doppler Flow and Imaging Study

Intravascular ultrasound (IVUS) imaging has been proved to be a safe and effective means to accurately assess coronary atherosclerotic disease. However, current IVUS probes can only provide a cross-sectional view of the blood vessel wall, lacking a forward field of view, which hinders the evaluation and diagnosis of atherosclerotic plaque. Furthermore, conventional IVUS probes usually use a single ultrasound transducer with a relatively low frequency, rendering them unable to achieve both high imaging resolution and deep penetration depth. In this paper, we propose a dual-mode miniature IVUS probe consisting of a micromachined dual-frequency (30 MHz and 80 MHz) side-looking ultrasound transducer for cross-sectional imaging and a 20 MHz forward-looking ultrasound transducer for blood flow detection. Ultrasonic imaging results demonstrate the side-looking dual-frequency transducers possess both deep penetration depth and high imaging resolution. Doppler blood flow experiments illustrate that the forward-looking ultrasound transducer can accurately evaluate blood flow velocity. This proposed dual-mode ultrasound probe exhibits excellent potential in diagnosing and assessing coronary atherosclerotic disease.