基于MRI心脏瓣膜支架建模的比较及分析

Comparison and analysis of modeling heart valve bracket based on magnetic resonance imaging

背景:当前心脏瓣膜手术所用的人工瓣膜有生物瓣膜和机械瓣膜,生物瓣膜瓣架的设计与加工决定了生物瓣膜的造型,从而决定了生物瓣膜的使用寿命。目的:根据空间几何方程构建出不同的瓣叶及瓣架模型,通过对比不同瓣叶及瓣架的变形及应力分布情况,获得一种较为合理的瓣架模型,再通过3D打印技术得到实体模型。方法:根据心脏瓣叶和瓣架的几何模型和数学模型绘制出抛物与椭圆2种心脏瓣架模型,用三维建模对心脏瓣膜瓣架建模,通过双向流固耦合分析研究瓣架在血液流场中的受力及变形。选择心脏瓣膜支架的打印方式和合适的打印材料,实现心脏瓣膜瓣架的3D打印成型。结果与结论:抛物瓣架与椭球瓣架的变形、最大主应力和最大剪切应力的分布规律相同,椭球瓣架的变形和所受应力都大于抛物瓣架,最大主应力和最大剪切应力都主要集中在瓣架与瓣叶结合的部分,瓣架的总变形、最大主应力和最大剪切应力都随着瓣架直径的增大而减小。

BACKGROUND:Currently,artificial valves used in heart valve operations include biological valves and mechanical valves.The design and processing of the biological valve bracket determine the shape of the biological valves,which in turn determines their service life.OBJECTIVE:Various lobe and bracket models were created based on the spatial geometric equation.Through a comparison of the deformation and stress distribution of various lobe and bracket models,a more rational bracket model was derived.Subsequently,3D printing technology was utilized to produce a solid model.METHODS:According to the geometric and mathematical models of the heart valve leaf and valve bracket,parabolic and ellipsoidal heart valve bracket models were created.Three-dimensional modeling was used to design the heart valve bracket.Two-way fluid-structure coupling analysis was conducted to analyze the force and deformation of the valve bracket in the blood flow field.An appropriate printing method and materials were selected to achieve 3D printing of the heart valve bracket.RESULTS AND CONCLUSION:The distribution rules of deformation,maximum principal stress,and maximum shear stress of the parabolic bracket and ellipsoidal bracket are the same.The deformation and stress of the ellipsoidal bracket were greater than those of the parabolic bracket.The distribution law of maximum principal stress and maximum shear stress was mainly concentrated in the joint part of the lobe and bracket.The total deformation,maximum principal stress,and maximum shear stress of the bracket decrease with the increase of the bracket diameter.