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背景:动脉瘤中置入支架后血液流动状态的改变,为研究支架置入后再狭窄的发生提供了前提和条件,而数值模拟分析是一种很好的技术手段。目的:探究支架置入对个体化颅内动脉瘤血液动力学的影响,以及支架表面剪切应力的分布特征。方法:依据1例颅内动脉瘤患者的CT影像数据,进行数据的提取、优化,建立个体化颅内动脉瘤实体化模型;设计矩形截面螺旋形支架的三维模型,并通过布尔运算,得到带有支架的动脉瘤模型,并通过对该模型支架表面剪切应力的分布情况来分析再狭窄发生的可能。结果与结论:通过探究不同血流速度与血液黏度对支架表面剪切应力的影响发现,在同一个时刻中支架表面大于40 Pa的剪切应力区域,随血流速度和血液黏度的增大而增大;而剪切应力不足0.5 Pa的区域,随血液黏度的增大有所减小,当速度为0时分布最大。该支架对于动脉瘤的生长或破裂起到了抑制作用,但发生再狭窄的区域很大,需要对支架进行优化或从新选型,以使支架的剪切应力保持在0.5-40 Pa的理想范围之中,并保证在心动周期的不同时刻里剪切应力的脉动变化尽可能减小,以达到防止支架置入后发生血管内部的再狭窄目的。
Background: The change of blood flow status after stent implantation in aneurysms provides preconditions and conditions for studying the occurrence of restenosis after stent implantation. Numerical simulation is a good technique. Objective: To investigate the influence of stent implantation on the hemodynamics of individual intracranial aneurysms and the distribution characteristics of shear stress on the stent surface. Methods: According to the CT image data of one patient with intracranial aneurysm, the data were extracted and optimized to establish the individualized model of intracranial aneurysm. The three-dimensional model of spiral scaffold with rectangular cross-section was designed, and the result of Boolean operation There is a stent-based aneurysm model and the possibility of restenosis is analyzed by the distribution of shear stress on the stent surface. RESULTS AND CONCLUSION: By investigating the influence of different blood flow velocity and blood viscosity on the shear stress on stent surface, it was found that the shear stress region of the stent surface larger than 40 Pa at the same time, with the increase of blood flow velocity and blood viscosity And the area with shear stress less than 0.5 Pa decreases with the increase of blood viscosity. When the velocity is 0, the distribution is the largest. The stent inhibits the growth or rupture of aneurysms but the area for restenosis is large and the stent needs to be optimized or re-sized to maintain the stent shear stress in the desired range of 0.5-40 Pa , And ensure that changes in the pulsation of shear stress are minimized at different moments of the cardiac cycle so as to prevent the restenosis inside the blood vessel after the stent is inserted.