Focused intravascular ultrasonic probe using dimpled transducer elements

•Focused intravascular ultrasonic probes were fabricated using dimple technique.•Probes based on PMN–PT single crystal and lead-free ceramic have good performance.•Ultrasonic images of wire phantom and vessels with good resolution were obtained. High-frequency focused intravascular ultrasonic probes were fabricated in this study using dimple technique based on PMN–PT single crystal and lead-free KNN–KBT–Mn ceramic. The center frequency, bandwidth, and insertion loss of the PMN–PT transducer were 34MHz, 75%, and 22.9dB, respectively. For the lead-free probe, the center frequency, bandwidth, and insertion loss were found to be 40MHz, 72%, and 28.8dB, respectively. The ultrasonic images of wire phantom and vessels with good resolution were obtained to evaluate the transducer performance. The −6dB axial and lateral resolutions of the PMN–PT probe were determined to be 58μm and 131μm, respectively. For the lead-free probe, the axial and lateral resolutions were found to be 44μm and 125μm, respectively. These results suggest that the mechanical dimpling technique has good potential in preparing focused transducers for intravascular ultrasound applications.