Research On Fusion Of Intravascular Ultrasound And Intravascular Optical Coherence Tomography Images

Intravascular ultrasound(IVUS) is a unique imaging tool to analyze the morphological vessel structures and make decisions about plaque presence. It utilizes a tiny ultrasound probe mounted on the tip of the cardiac catheter to obtain cross-sectional images with better detection depth, but lower spatial resolution. Intravascular optical coherence tomography(IV-OCT) is a new intravascular imaging modality. Similar to IVUS, it combines optical technology with ultra-sensitive detector to obtain cross-sectional images of the vessel lumen, with high resolution but poor tissue penetration.This study aims to fuse IV-OCT and IVUS image data acquired from a vessel segment to obtain comprehensive accessment and description of the vessel wall and atherosclerotic plaques. The advantages of strong tissue penetration of IVUS and high resolution of IV-OCT imaging are combined to assist the computer-aided diagnosis and interventional treatment planning of coronary arterial diseases.Image registration is an important prerequisite for image fusion. In this dissertation, two registration methods based on feature points and contour feature are presented. The former needs to detect landmarkers, such as bifurcation and calcification, and register the images according to them. The latter needs to extract vessel lumen contours from IV-OCT and IVUS images, and register both images based on lumen contours. Then, IVUS and IV-OCT images are fused based on wavelet transform algorithm and Bandelet fusion algorithm. The experimental results with clinically acquired image are subjectively and objectively evaluated. Also, the advantages and limits of both methods are discussed.