Validating a bimodal intravascular ultrasound (IVUS) and near-infrared fluorescence (NIRF) catheter for atherosclerotic plaque detection in rabbits.

Coronary artery disease is characterized by atherosclerotic plaque formation. Despite impressive advances in intravascular imaging modalities, in vivo molecular plaque characterization remains challenging, and different multimodality imaging systems have been proposed. We validated an engineered bimodal intravascular ultrasound imaging (IVUS) / near-infrared fluorescence (NIRF) imaging catheter in vivo using a balloon injury atherosclerosis rabbit model. Rabbit aortas and right iliac arteries were scanned in vivo after indocyanine green (ICG) injection, and compared to corresponding ex vivo fluorescence and white light images. Areas of ICG accumulation were colocalized with macroscopic atherosclerotic plaque formation. In vivo imaging was performed with the bimodal catheter integrating ICG-induced fluorescence signals into cross-sectional IVUS imaging. In vivo ICG accumulation corresponded to ex vivo fluorescence signal intensity and IVUS identified plaques.