An intravascular photoacoustic imaging catheter

We developed an integrated intravascular photoacoustic (IVPA) and ultrasound (IVUS) catheter to image atherosclerotic plaque structure and composition, which are important determinants of plaque vulnerability. Our catheter comprises an angle-polished optical fiber and a 30 MHz single-element piezoelectric transducer. The ultrasonic transducer was optically isolated to eliminate artifacts in the photoacoustic (PA) image. We showed its imaging performance using a vessel phantom and quantified its imaging characteristics by doing measurements on isolated point targets. The axial and lateral point spread function widths were 110 μm and 550 μm respectively for IVPA imaging and 89 μm and 420 μm respectively for IVUS imaging. The signal to noise ratios were 50 dB (PA) and 54 dB (US).