颅内典型囊性动脉瘤的三维数值模拟及血流动力学分析

Three-dimension numerical simulation and hemodynamic analysis of the intracranial typical saccular aneurysms

目的应用计算流体力学软件进行三维数值模拟,分析不同类型动脉瘤的血液动力学特性。方法根据动脉瘤瘤体与载瘤动脉的关系,将颅内典型囊性动脉瘤分为A(动脉瘤位于血管弓背侧)、B(动脉瘤位于血管弓内侧)、C(分叉部动脉瘤,瘤轴平面与载瘤动脉轴共面),D(分叉部动脉瘤,瘤轴平面与载瘤动脉轴不共面)四类。联合应用Matlab软件、Ansys软件、Fluent软件及自写程序对颅内囊性动脉瘤进行计算机数值模拟分析。结果颅内动脉瘤模型流入道的血流速度、动压及壁面切应力最高,流出道次之,顶部最低;A、B、D类动脉瘤冲击域壁面切应力最大;C类动脉瘤内动脉压普遍较高。结论对A、B、D类动脉瘤,冲击域壁面切应力最大可能是动脉瘤生长的主要因素,而其顶部壁面切应力不足可能是破裂的主要因素之一;对C类动脉瘤,动脉瘤内动压较高是其破裂的主要因素。

Objective To analyze the hemodynamic features of different types of aneurysms with the computational fluid dynamic （CFD） softwares. Methods The typical saccular aneurysms were classified to 4 types according to the relationship between the aneurysms and parent artery： A （aneurysms on the dorsal side of the vascular arch）, B （aneurysm on the inner side of the vascular arch）, C （coplanar bifurcation aneurysm）, and D （non-coplanar bifurcation aneurysm）. Matlab, Ansys, and Fluent soft-wares were used to simulate the blood flow of the typical saccular aneurisms. Results The dynamic pressure, blood velocity and wall shear stress were highest in the inflow tract of the aneurismal models, lower in the outflow tract, and lowest in the top region of the aneurysm. The shear stress of ＂impact zone＂ in types A, B, D ofaneurysm was highest; the dynamic pressure in type C was generally higher than others. Conclusion The highest walt shear stress may contribute to growth of the aneurysms in types A, B, D, however, the lower wall shear stress on the top of the aneurysms may contribute to rupture of the aneurysms. A higher dynamic pressure may play an important role in the rupture of type C aneurysm.