Cardiac Modeling And Mechanical Analysis Based On Isogeometric Analysis

Recently, modeling and mechanical analysis of the heart become a hot research spot to use the model to analyze the motions and functions of the cardiac left ventricle (LV), in which the strain and stress analysis can reflect the regional function of the LV and realize early diagnosis and treatment of disease, so the research has become particularly important.The traditional LV model which based on the finite element analysis (FEA) is lack of continuity, and the accuracy is not high enough either. Furthermore, these models can’t precisely calculate the LV’s stress, strain or functional parameters. Therefore, this paper proposes a modeling method and a mechanical analysis method based on isogeometric analysis (IGA), and these two methods are applied to the LV’s modeling and mechanical analysis. The continuous stress and strain obtained by the IGA LV model are more corresponding to the clinical distribution of stress and strain. Works and contributions of this paper are as follows:1. With the situation that traditional LV model by FEA method is lack of accuracy, this paper firstly build the LV model by the IGA method. The control points and basis function calculated in this method depend on the feature points by image segmentation, while the area between the inner and outer wall is fitted with the IGA entity simulation and interpolation method in order to obtain a solid LV model with control points. What’s more, a new method of moving control points is used to adjust and modify the model. This method promises the model to be more accurate in comparison with traditional models.2. With the situation that the stress and strain distribution by FEA method is lack of continuity, this paper also proposes a stress-strain calculation method based on the IGA. This method uses the boundary value method to build the weak form of the problem, and solves the form by Galerkin method. At last, the strain and stress are calculated with corresponding visual results. This paper makes a comparison between the FEA and IGA in mechanical analysis as well, experimental results show that stress and strain distribution of the LV can be given by both of them, but by comparing the results of them, it is shown that the latter one can give smooth and continuous calculation of left ventricular stress and strain, which can more truly reflect the left ventricular stress and strain distribution, so it is better than the former one.