出口边界条件和壁厚对冠状动脉壁面剪切力和冯米塞斯应力的影响

发布时间：2018-03-16 08:14

  本文选题：冠状动脉　切入点：流固耦合　出处：《中国生物医学工程学报》2016年04期 　论文类型：期刊论文

【摘要】：探讨基于个体化患者计算机断层血管造影(CTA)影像的冠状动脉流固耦合(FSI)数值分析中,不同出口边界条件和血管壁模型对时间平均壁面剪切力(TAWSS)和冯米塞斯应力(VMS)的影响。根据患者CTA影像重建右冠状动脉(RCA)管腔流域三维几何;将管腔流域表面向外扩张0.5 mm,形成均匀厚度血管壁;运用类似虚拟去除斑块的方法建立不均匀厚度血管壁模型。FSI分析时,分别给予zero和impedance两种出口边界条件;获得从舒张末期开始心动周期主要时间点TAWSS和VMS的分布,比较不同模型结果的差异。结果表明,两种出口边界条件下,TAWSS空间分布基本一致,且血管狭窄段均高于其他部位;zero条件下峰值VMS出现在压强最大时刻点0.42 s,而impedance条件下峰值VMS出现在入口血流速度最大时刻点0.64 s,并且达到前者的20倍。同是impedance出口边界条件时,TAWSS分布基本一致,没有显著性差异;两种血管壁模型中,VMS的分布一致,血管狭窄段比其他部位低,但是不均匀厚度血管壁模型中局部位置VMS绝对值高于均匀壁厚血管壁模型。医学影像技术的发展可以提供更高精度的冠脉结构以及出入口速度和压强边界条件,不但对研究血流动力学以及结构力学因素与心血管疾病的关系具有重要意义,也可以更好的服务于患者个体化诊断与治疗。
[Abstract]:To investigate the numerical analysis of FSIs based on computed tomography angiography (CTAA) images of individual patients with coronary artery flow and solid coupling (FSI). The effects of different outlet boundary conditions and vascular wall models on time-averaged wall shear stress (TAWSS) and von Mises stress (VMS) were studied. Three-dimensional geometry of the lumen of right coronary artery was reconstructed by CTA images. The vascular wall with uniform thickness was formed by extending the surface of the vessel basin to 0.5 mm, and the non-uniform thickness vascular wall model was established by using the method of virtual plaque removal. The zero and impedance were given two exit boundary conditions, respectively. The distributions of TAWSS and VMS at the main time points of cardiac cycle starting from the end of diastole were obtained, and the differences between the results of different models were compared. The results showed that the spatial distribution of TAWSS was basically the same under the two exit boundary conditions. The peak VMS appeared at the maximum pressure point of 0.42 s under the condition of impedance, and the peak VMS appeared at the point of the maximum flow velocity at the inlet point of 0.64 s on the impedance condition, and reached 20 times of the former, which was 20 times of that of the former. The distribution of TAWSS is basically the same at the mouth boundary condition. There was no significant difference in the distribution of VMS between the two vessel wall models. However, the absolute value of VMS in the uneven thickness vascular wall model is higher than that in the uniform wall wall model. The development of medical imaging technology can provide more accurate coronary artery structure, inlet velocity and pressure boundary conditions. Not only is it important to study the relationship between hemodynamics, structural mechanics and cardiovascular disease, but also can serve the individual diagnosis and treatment of patients better.
【作者单位】： 首都医科大学附属北京安贞医院;北京市心肺血管疾病研究所;
【基金】：首都医学发展科研基金(2011-1005-02)
【分类号】：R816.2
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本文编号：1619063