This research focuses on the development and use of an ultrafast integrated IVUS-OCT system to image and identify vulnerable atherosclerotic plaque in vivo. By providing ultrafast imaging of arteries with high resolution and deep penetration depth simultaneously, this hybrid IVUS-OCT technology opens new and safe opportunities to evaluate in real-time the risk of plaques, identify vulnerable plaques, and optimize treatment decisions.
A system to simultaneously provide IVUS and OCT functions at an imaging speed of over 30 frames per second was thought to be impossible. In this dissertation, we overcame the speed limit of integrated IVUS-OCT system, the fundamental barrier hindering the clinical application of the integrated IVUS-OCT technique. We demonstrated the ability to perform simultaneous IVUS-OCT imaging at 72 frames per second safely in vivo. By using this ultrafast system, the risk of catheter-induced spasm and a great amount of toxic contrast agent is significantly reduced. This breakthrough enables the translation of this technology into clinical practice.
Nine atherosclerotic-model rabbits and four swine were imaged to validate the design of our imaging system and catheters. Images were obtained in these animals without complications. For the first time, this study shows that an integrated intracoronary IVUS-OCT system is feasible and safe to use in vivo to detect atherosclerotic plaques. To avoid severe side effects of contrast agents, alternative IVUS-OCT flushing agents were investigated. Ex vivo imaging of over 300 human coronary artery regions of interest was also performed to quantitatively evaluate the diagnostic accuracy of the integrated system. The in vivo animal imaging and ex vivo human cadaver diagnostic accuracy test elucidated that this technique can facilitate a more powerful tool to explore the development of plaques and holds great hope for a more accurate assessment of vulnerable plaque in patients.
In addition, other applications of the integrated IVUS-OCT system were also explored. Ex vivo studies were performed to image stent and bile duct cancer.
Last but not least, a new probe design for tracking the trajectory of the imaging catheter while perform imaging, was developed and tested in porcine trachea ex vivo.