基于三维医学影像的脑动脉瘤内血液流动的数值模拟

Numerical simulation of blood flow in image-based cerebral aneurysms

目的利用数值模拟研究具有病人特异性的脑动脉瘤内的血液流动,为脑动脉瘤的破裂风险的评价和动脉瘤介入栓塞后复发风险的评价提供帮助。方法从两例脑动脉瘤病人的3D-RA数据中重建动脉瘤几何模型,血液流变学模型选择假塑性非牛顿流体模型,利用商用CFD软件Fluent对两例动脉瘤内的血液流动进行数值模拟。结果数值模拟给出了动脉瘤内的流线图、重要截面上的速度分布图、壁面上的切应力分布和压力分布图。并且绘制了在收缩期时刻动脉瘤颈部和瘤顶部各20个点上的壁面切应力和压力的变化情况。结论血流动力学因素如流速、压力、壁面切应力、流动对壁面的冲击状况等因素与动脉瘤的生长和破裂密切相关,而由于脑动脉瘤形态各异、载瘤动脉与动脉瘤体的几何关系复杂,因此,具有病人特异性的数值模拟对于研究动脉瘤破裂和复发风险具有重要价值。动脉瘤颈部的壁面切应力的波动的变化规律并不相同,需要进一步研究壁面切应力的波动与脑动脉瘤生长与破裂之间的定量关系。

ObjectJvs Simulate the blood flow numerically in patient-specific cerebral aneurysms and help assessing the risks of rupture and reoccurrence of cerebral aneurysms in clinic. Method Geometrical models were constructed from three-dimensional rotational angiography data, Herschel-Bulkley non-Newtonian fluid model was chosen for the blood, and the commercial CFD sotfware was employed to simulate the blood flow in the two patient-specific computational models. Result The streamlines, the velocity fields in important cross sections, the wall shear stress distribution and total pressure distribution on the aneurysmal wall were obtained. Furthermore, the graphs of wall shear stress and total pressure, at20 points of the neck and top of each aneurysm respectively, at systolic time, were plotted. Conclusions Hemodynamic factors play important roles in the growth and rupture of cerebral aneurysms and patient-specific CFD simulation of blood flow in cerebral aneurysm can make a contribution in studying the hemodynamics in cerebral aneurysms. Distribution of wall shear stress is different from that of unsteady index of wall shear stress at the neck of the aneurysm, and the relationship between the oscillation of wall shear stress and the risks of rupture and reoccurrence of the aneurysm should be studied.