Study On 3D Modeling And Hemodynamics Of Coronary Artery

At present,cardiovascular disease has become the main killer of human health,especially the disease occurs in the coronary artery is becoming the main threat to health.Therefore,it is necessary to combine the technology of biomedical image processing and computational fluid dynamics to assist the decision making of coronary artery disease,Not only through the establishment of three-dimensional images of coronary artery can provide medical workers with intuitive,image analysis of the disease,but also it can provide theoretical basis and research methods for medical workers to study the related diseases by analyzing the mutual coupling effect between the blood vessels and the elastic tube wall.In the process of biomedical image processing,the different angle angiography formed two-dimensional image reconstruction of 3D vascular image can be used to reflect the coronary vascular shape,severity,quantitative parameters and other information,so as to facilitate the medical workers intuitively and accurately judge on vascular lesions.According to the influence of noise and low contrast on the accuracy of coronary angiography,in this paper,after fully analyzing the characteristics of coronary angiography images,objective to extract the blood vessel according to the coronary angiography image sequence,by distinguishing the changes of coronary and background gray trend of coronary angiography image sequence to use high frequency filter enhancement in the coronary arteries and reduce the noise point.Then,the morphological improvement method and the threshold value are used to enhance the blood vessels,reduce the noise and extract the coronary vessels;The skeleton of the coronary artery was extracted accurately by morphological thinning method,and the “8-chain” code was used to carry out the mathematical expression.Then,the diameter of coronary artery was extracted by disc rolling method;Aiming at the 3D modeling of coronary artery,the imaging principle,the contrast angle,the space coordinate transformation and the parameters of 3D reconstruction are studied firstly,Then,based on the discrete points of the vascular skeleton of the coronary angiogram images with different contrast angles,the discrete points of the threedimensional skeleton of the coronary artery are solved.Then,the B spline is used to interpolate the blood vessel point,which makes the 3D skeleton of the blood vessel have continuous visibility.In the judgment of coronary artery lesions in concrete at the same time,also to pathogenesis by calculating fluid dynamics to study the coronary artery lesions,so as to the treatment of coronary vascular disease plays a supporting role in the decision-making.Among them,the information about the shape of the vessel and the specific quantitative parameters obtained from the three-dimensional modeling of coronary arteries plays a crucial role in the computational study of the blood dynamics.According to the study of blood flow in the coronary artery,three representative vascular models were selected,which were tapered vessels,local stenosis vessels,and different diameter vessels.According to the basic theory of fluid elasticity,the Navier-stokes equation and the equation of motion of blood vessel wall are simplified.The establishment of compatible coupling conditions of blood flow and vascular wall motion equations of Euler Lagrange method,and according to the pulse waveform,the shape of the blood vessel,establish blood flow velocity expression,combined with the vessel wall motion equation is derived by the expression of vascular wall and vascular wall deformation pressure.In the process of blood flow,the pressure drop will be produced due to the characteristic impedance of the blood vessel.Therefore,the pressure drop of each segment of the vessel is obtained by calculating the characteristic impedance and pulse wave velocity.This topic through the analysis of specific examples of vascular,pulse wave in a cardiac cycle related vascular parameters: radius,thickness,elastic modulus,different pressure,pressure drop and vascular stenosis degree of different stress and deformation effect on the vascular wall.In order to verify the theoretical part,the fluid solid coupling module of Ansys finite element software is used to conduct numerical simulation under a given value.