Research On Optimal Angiographic Viewing Angles For The Segment Of Interest And Fusion From Intravascular Ultrasound And Angiography

Despite of advances in cardiovascular imaging, coronary angiography remains the"gold standard"for the assessment of coronary artery disease. Coronary angiography is limited by its two-dimensional (2D) representation of three-dimensional (3D) structures. Vessel overlapping and foreshortening in angiographic images may cause errors in the assessment of lesions or the selection and placement of stents, and can be influenced by the viewing angles. In this paper, a method is proposed to calculate the optimal angiographic viewing angles of segment of interest based on 3D reconstruction of coronary arterial tree. Quantitative coronary angiography (QCA) based on the optimal angiographic viewing angles can yield more accurate results, and can be utilized to assist interventional cardiologists in planning a coronary intervention.In the rapidly evolving field of intravascular ultrasound (IVUS), the assessment of vessel morphology still lacks a geometrically correct 3D reconstruction. The IVUS frames are usually stacked up to form a straight vessel, neglecting curvature and the axial twisting of the catheter during the pullback. This paper presents a method for geometrically correct reconstruction of IVUS images by fusion with angiography, thus combining the advantages of both modalities.Major work of this dissertation can be included in five parts as follows:1. Calculation of angiographic viewing angles minimizing vessel foreshortening This paper proposes a method to calculate the percent foreshortening of vessel. In addition, three methods are studied for calculation of angiographic viewing angles minimizing vessel foreshortening of segment of interest, including Geometric Solution, Minimization of Vessel Foreshortening and Plane Fitting, and their characteristics in terms of accuracy and computation cost are analyzed and compared.2. Calculation of optimal angiographic viewing angles The methods are presented to calculate angiographic viewing angles minimizing vessel overlapping of segment of interest. The optimal angiographic viewing angles are obtained by minimizing vessel overlapping and foreshortening.3. Optimization of translation vector in transformation The transformation in the forms of a rotation matrix and a translation vector characterizes the spatial relationship between imaging coordinate systems in two different views, which is important for 3D reconstruction of coronary arterial tree. In this paper, bifurcations and endpoints are used to optimize the translation vectors in...