High frequency (IVUS) ultrasound transducer technology - applications and challenges

High frequency (10 -50 MHz) transducers find application in intravascular ultrasound (IVUS) imaging of coronary diseases. Plaque in the arterial vessels leads to decrease in the lumen and can cause high blood pressure and induce heart failure or vessel rupture. Intravascular imaging is a useful addition to external imaging modalities such as angiography to visualize areas of plaque for placement of stents as a preventive disease treatment. This imaging modality requires the transducer to be placed within the blood vessel, typically by introduction of a catheter. Unlike conventional external ultrasound transducers, IVUS materials are limited in design by the necessity to be integrated into a catheter. Typical dimensions of IVUS catheters are 0.9 -1.2 mm in outer diameter, requiring the transducer to be even smaller. This paper presents design limitations of ultrasonic transducers.