【作者】 顾兆勇；

【导师】 乔爱科；

【作者基本信息】 北京工业大学 ， 机械设计及理论， 2009， 硕士

【摘要】 管腔内支架治疗技术己发展成为现代医学中备受关注并具有广阔发展前景的微创治疗技术。动脉瘤支架介入治疗的疗效受到诸多因素的影响,包括支架形状(螺旋状、网格状等)、支架丝截面形状、通透率、支架放置位置、支架的连接、支架伸缩性等。为了探讨不同结构的血管内支架对颅内复杂动脉瘤的血液动力学特性的影响,本文通过CAD软件构建了蜿蜒型颅内动脉瘤和四种不同结构裸支架(截面形状和通透率不同)的三维实体模型,利用计算流体力学方法,借助于有限元软件ANSYS11.0对不同结构内支架分别植入蜿蜒型颅内动脉瘤前后进行仿真研究,提取和分析了支架植入动脉瘤前后瘤腔内的流动情形、压力和壁面切应力等血流动力学参数。结果表明支架植入动脉瘤后瘤腔内的血流速度被大大削弱,圆顶突起处局部高压力明显减弱,沿瘤腔壁面的压力也得到明显降低并且分布也均衡了很多,末端唇缘处局部高切应力消失了,出现的是较小且均衡的切应力。设计采用的三角形截面支架由于血液流入和流出时的流阻不同,导致该支架植入动脉瘤后影响瘤腔血流不同,从而产生了动脉瘤腔内的血流动力学明显差异,而优越于传统圆形截面支架。这可以为支架结构设计提供一些理论指导意义。更多还原

【Abstract】 As a minimally invasive treatment technique, endovascular stent intervention technology has been accepted by modern medicine, which has broad prospective for development. However, the efficacy of stent intervention is affected by many factors, including the stent shape (spiral, grid, etc), cross-section of stent wire, porosity, stent placement, stent connector, stent flexibility and so on.Endovascular stents with different stent shapes or wire cross-section shapes have different effects on the hemodynamics of basilar aneurysms. In order to get quantitative understanding of this kind of difference, geometrically virtual models of three-dimensional sinuous aneurysms and four types of mesh stents (different porosity and different wire cross-section shapes) were constructed using CAD software, and simulations of stented and nonstented models were performed respectively using finite element software ANSYS11.0 according to CFD method. Hemodynamics data were extracted and analyzed in terms of flow field, pressure and wall shear stress.The result demonstrated that the velocity of blood flow in stented model is greatly weaken than the nonstented model, and the pressure along the wall of the distal aneurysm is also decreased and more uniform, and the locally elevated WSSs at the proximal lip of the distal aneurysm disappeared, instead small and uniform WSSs distribute along a majority of the aneurismal wall after stent intervention.It can be concluded that the new type of trianglualr stent with lower porosity has more superiority than other stents in weakening impact of blood to aneurismal wall and decreasing local high pressure and WSS. The flow resistance of the new stent with triangular cross-section is different when blood flows in and out of the aneurismal sac, and thus brings about different hemodynamics in aneurysms after the stent intervention. The stent with triangle section is more suitable for sinuous basilar aneurysms comparatively. The present study can provide some theoretical guidance to structural design of endovascular stent.更多还原