脑动脉瘤血管支架的结构设计及其血流场分析

发布时间：2018-01-05 12:32

本文关键词：脑动脉瘤血管支架的结构设计及其血流场分析　出处：《新疆大学》2017年硕士论文　论文类型：学位论文

【摘要】：背景脑动脉瘤是人体脑部的血管不正常的突起或者血管的增大膨胀,加之长期以往血流冲击形成血块,引起血管狭窄、脑部供血不足或者脑部血管破裂最后死亡的疾病。现代医学中临床主要的治疗手段是手术治疗,但存在着很大风险,因此提出了支架治疗动脉瘤的方法。目的研究支架的植入与血流场的作用机理以及不同变量条件对支架植入后血流场的变化情况,来判断支架结构设计的合理性,为进一步探究植入支架后的动脉瘤的动力学参数与动脉瘤再狭窄、破裂之间的关系。方法根据临床病人的CT数据,采用MIMICS软件建立脑动脉瘤的切片模型。表面模型用逆向工程软件进行优化处理,再经过三角模型的NURBS优化处理,结果个体化脑动脉瘤模型的建立;然后,根据动脉瘤形状及尺寸,通过UG设计了三种血管支架的模型(C型、G型、H型),接下来分析模型的特征,包括血管支架的柔顺性、血管支架的径向支撑力、血管支架的表面覆盖率分析及血管支架的疲劳寿命分析;最后,将设计好的三种支架装配到构建的动脉瘤模型,采用双向流固耦合的方法对装配模型进行了血流场特性分析,包括血流速度变化、血流压力变化、壁面剪切力变化及壁面变形情况等。结果与结论通过ANSYS模拟仿真最终得到了支架的柔顺性分析图、支架的支撑力分析图、支架的寿命图、支架的表面覆盖率分析图,对三种支架特性进行综合评价,得出H型支架优于其他两种支架(良好的柔顺性、较强的径向支撑力、持久的抵抗疲劳强度及较大的表面覆盖率);其次进行支架植入后得到血流场的血流速度图、血流压力图、血流壁面剪切力图、壁面变形分析图。得出了在一个心动周期0-0.8s内,四个典型时刻即0.05s、0.09s、0.26s、0.32s的流速、壁面切应力、壁面压力均减小了;三种支架分别在0.09s、0.32s时刻壁面切应力减小程度依次是G型、C型、H型;H型支架壁面剪切力在0.34s时刻减小最小;三种支架的压力中C型支架的压力范围在398-407Pa之间,压力变形最小在血流入口处;最后用10位患者统计数据进行数据验证,得出文章方法的可行性。
[Abstract]:Background Cerebral aneurysms are abnormal processes of blood vessels or dilation of blood vessels in the human brain, combined with blood clots formed by blood flow impact for a long time, resulting in stenosis of blood vessels. A disease in which insufficient blood supply to the brain or the eventual death of a ruptured blood vessel in the brain. Surgical treatment is the main clinical treatment in modern medicine, but there are significant risks. Objective to study the mechanism of stent implantation and blood flow field and the changes of blood flow field after stent implantation under different variable conditions. To determine the rationality of stent structure design, in order to further explore the relationship between the dynamic parameters and restenosis and rupture of the aneurysm after stent implantation. Methods according to the CT data of clinical patients. The slice model of cerebral aneurysm was established by MIMICS software. The surface model was optimized by reverse engineering software and then optimized by NURBS of triangle model. Results the individualized cerebral aneurysm model was established. Then, according to the shape and size of aneurysm, three kinds of angiostents were designed by UG. Then, the characteristics of the model, including the flexibility of the stent, were analyzed. The radial supporting force of vascular stent, the surface coverage of vascular stent and the fatigue life of vascular stent were analyzed. Finally, three kinds of scaffolds were assembled into the aneurysm model, and the characteristics of blood flow field were analyzed by two-way fluid-solid coupling method, including the changes of blood flow velocity and blood pressure. Results and conclusions the ANSYS simulation results and conclusions the support analysis diagram, support force analysis diagram and life diagram of the support are obtained by ANSYS simulation. Analysis of the surface coverage of the scaffold, comprehensive evaluation of the characteristics of the three scaffolds, it is concluded that the H-type bracket is superior to the other two kinds of scaffolds (good flexibility, strong radial support. Durable fatigue resistance and greater surface coverage; Secondly, the blood flow velocity map, blood pressure map, wall shear force and wall deformation analysis were obtained after stent implantation. The results were obtained within 0-0.8 s of a cardiac cycle. The shear stress and pressure of the wall are all reduced at the flow rate of 0.05s0. 09s / 0. 26s / 0.32s at four typical times. At 0.09s / 0.32s, the shear stress of the three kinds of scaffolds is G / C / H respectively. The shear force on the wall of the H-type bracket decreases to a minimum at 0.34 s. The pressure range of C type stent is between 398-407 Pa and the pressure deformation is minimum at the entrance of blood flow. Finally, 10 patients with statistical data were used to verify the data, and the feasibility of the method was obtained.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R743;R318.08

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