Motion Analysis Of Mitral Valve In Children Based On Three Dimensional Echocardiography

The quantitative measurement and analysis of static and dynamic state of mitral annulus and mitral valve leaflet are important to the diagnosis and therapy of some heart disease. Thanks to the three dimensional echocardiography, it can indicate the complex inside structure of heart. Cooperating with Shanghai children medical center, we present the work of measurement and analysis of mitral valve, especially the mitral annulus and mitral valve leaflet by three dimensional echocardiographs in this thesis.The innovation of this thesis is as following:1). According to actual characteristic of mitral valve, complex mitral valve 3D motion was decomposed into global motion and regional motion. Companied with the motion of heart due to the aspiration, mitral valve has global motion throughout the cardiac cycle. The mitral valve lies between the heart's left atrium and left ventricle, therefore, it has regional motion with two leaflets opening and closing together like a pair of swinging doors. Based on the three dimensional echocardiography, a reference plane of mitral annulus was proposed to eliminate the global motion, and provide a reference plane for measurement the static and dynamic parameters of the mitral annulus. Experimental results show that our approach can provide a more reliable measure of the mitral annulus dynamic behavior.2) As the size of heart is enlarged with the growth of children, the parameters related to the dynamics of the mitral annulus varies from person to person. In order to compare the parameters of healthy children with patients, the measured parameters of the mitral annulus must be normalized. In this thesis, we introduce the classification method of pattern recognition to combine the measured parameters of the mitral annulus with the associated left ventricular volume. Experimental results show that it is possible to distinguishing the healthy children from the patients, that is to say, our approach can provide a valuable suggestions for clinical diagnosis and quantitative assessments.3) Based on real-time three-dimensional echocardiography images, a dynamic analysis method describing mitral annulus represented by connected curve angle chain is suggested. The traditional methods of describing the mitral valve are composed of the perimeter, the orifice area and the area of mitral annulus. We have proved that the proposed connected curve angle chain is invariant to rotation, scaling, and translation. Experimental results show that the proposed approach can be feasibly used for describing the mitral valve, and can quickly get motion of mitral annulus throughout the cardiac cycle.4) We have developed a package of computer-aided visualization of 3D echocardiography image and quantitative measurements of mitral annulus and mitral valve leaflet. At the beginning, the boundary points on the mitral annulus are marked by doctors interactively. Since these marked points are not distributed uniformly and sequentially, it is necessary in the second step to re-arrange these points into a set of sequences of points on a contour of the saddle-shaped mitral annulus. Thirdly, in order to assess the geometry of the 3D mitral annulus, it is modeled by a 3D non-uniform rational B-spline (NURBS). At last, the parameters related to the dynamics of the mitral annulus throughout the cardiac cycle are calculated in a 3D Cartesian coordinate system.