Evaluation of Intravascular Ultrasound Catheter-Based Transducers Using the Resolution Integral.

Intravascular ultrasound (IVUS) catheters are a specialist imaging modality used in the assessment of cardiovascular disease. The ultrasound transducer may either be of single-element mechanical or phased-array design. Because of their design and operating frequencies (10-45 MHz), evaluation of the imaging performance is not possible with commercially available ultrasound test objects. An existing test object, the Edinburgh Pipe Phantom, was modified to allow measurement of resolution integral (R), depth of field (Lr) and characteristic resolution (Dr) of IVUS catheters. In total, seven IVUS catheters, from two manufacturers and of both single-element mechanical and phased-array design, were tested to provide a measure of performance over different frequencies and technologies. Measurements of R for the tested IVUS catheters ranged from 11.9 to 18.8. The modified Edinburgh Pipe Phantom therefore allows catheter-based ultrasound probes to be evaluated scientifically and their performance to be seen in relation to other similar ultrasound technologies such as pre-clinical ultrasound and endoscopic ultrasound.