Integrated IVUS-OCT for real-time imaging of coronary atherosclerosis.

OBJECTIVE: Combined use of optical coherence tomography (OCT) and intravascular ultrasound (IVUS) is a potential method for accurate assessment of plaques characteristics and vulnerability. The aim of this study is to develop and evaluate the feasibility of a fully integrated intracoronary OCT-IVUS imaging technique to visualize plaques in living animals. BACKGROUND: In vivo imaging of plaques by an integrated OCT-IVUS system has not been reported. METHODS: Simultaneous real-time OCT-IVUS imaging is performed using an integrated OCT-IVUS system and a single fully-integrated catheter with a 3.6F outer-diameter same as a commercial IVUS catheter. RESULTS: To verify in vivo imaging capability of this technique, five atherosclerotic-model rabbits and a swine were imaged. Images were obtained in these animals without complications. Linear regression shows a high correlation between rabbit plaque sizes determined from histology and OCT/IVUS estimated plaque sizes (R2=0.955, P<0.001 between OCT and histology; R2=0.970, P<0.001 between IVUS and histology). Classification of plaque types and quantitative analysis of plaque sizes were performed in vitro using cadaver coronary segments (n=14). CONCLUSIONS: For the first time, this study shows that an integrated intracoronary OCT-IVUS system is feasible and safe to use in vivo to detect atherosclerotic plaques. This technique provides high resolution and deep penetration capability simultaneously which can facilitate a more powerful tool to explore the development of plaques and may lead to a more accurate assessment of vulnerable plaques in patients.