数值模拟描述血管壁厚度对复杂颅内动脉瘤流固耦合分析结果的影响

摘要

背景：颅内动脉瘤病死率高，有限元分析预测其破裂风险目前成了一个热门课题。有限元分析需要可靠的流固耦合模型，动脉瘤的血液模型很易得到，而血管壁模型无法直接获得，只能人为设置，这可能对计算结果造成影响。目的：探讨有限元建模时血管壁厚度的设置对复杂颅内动脉瘤流固耦合分析的影响，为颅内动脉瘤的数值模拟研究提供更可靠的建模方法。　　方法：通过3D脑血管造影取得一67岁男性患者左侧颈内动脉颅内段串联动脉瘤的三维数值模型。术后通过管壁增厚的方法构建出血管壁模型，人为设置的壁厚为0.3，0.4，0.5，0.6 mm，得到4个流固耦合模型。根据术中测得的数据，利用有限元法模拟分析流固耦合作用下颈内动脉串联动脉瘤的血液动力学特征，比较4个模型计算结果之间的差异。　　结果与结论：4个模型的血液流线图、血液压力降图、血管内壁壁面切应力均无差异(P >0.05)。4个模型血管壁变形最明显处均在颈内动脉C 2段，但血管壁越厚者最大变形量越小(P<0.01)。4个模型血管壁Von Mises应力均在I，J两点处达到局部最大值，血管壁越薄者局部最大值越大(P<0.01)。证实血管壁厚度的设置会对复杂颅内动脉瘤的流固耦合分析结果造成影响，欲得到准确计算结果需根据实际情况设置合适厚度。%BACKGROUND:Intracranial aneurysms have a high mortality, and finite element analysis to predict fracture risk has become a hot topic at present. Finite element analysis requires reliable fluid-structure interaction model, blood model of aneurysm is very easy to obtain, but the vascular wal model can not be obtained directly, only by artificial settings, which may have an impact on calculation results. OBJECTIVE:To investigate the effects of vascular wal thickness on fluid-structure interaction analysis in finite element modeling of complex intracranial aneurysms, and provide a more reliable method of finite element modeling for the numerical simulation study of intracranial aneurysms. METHODS:A three-dimensional numerical model of tandem left intracranial internal carotid artery aneurysms of a 67-year-old man was obtained by three-dimensional angiography. Four fluid-structure models were got postoperatively by thickening vascular wal , which were artificial y set for 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm. According to intraoperative measured data, dynamic characteristics of fluid-structure interaction of tandem internal carotid artery aneurysms were simulated by the finite element method, comparing four models to calculate the difference between the results. RESULTS AND CONCLUSION:Among the four models, there were no difference in blood flow chart, blood pressure drop chart and wal shear stress chart (P>0.05). The deformation of the vascular wal was the most obvious in C 2 segment of the internal carotid artery, and the thicker vessel wal was accompanied by the more apparent deformation (P<0.01). Von Mises stress in the vessel wal of the four models reached a local maximum in the I and J points, the thinner vessel wal was accompanied by the larger local maximum (P<0.01). The settings of vascular wel may affect the fluid-structure interaction analysis of complex intracranial aneurysms and appropriate thickness settings wil obtain accurate calculation.