颅内动脉旁瘤的血液动力学的三维数值模拟

Three-Dimensional Numerical Simulation of Hemodynamics for Intracranial Lateral Aneurysms

数值模拟颅内动脉瘤的血液动力学。假定血液为牛顿流体和血管壁为刚性壁 ,采用人工压缩性方法求解三维Navier Stokes方程。在稳态和脉动的情形下计算了颅内动脉瘤的剪应力和压力等血液动力学因素随空间和时间的变化 ,以及颅内动脉瘤的几何形状、雷诺数等参数对血液动力学因素的影响。得到的主要结论是 :无论在稳态还是脉动条件下 ,对于生长初期的颅内动脉瘤 ,瘤的深度越大 ,远端的壁面剪应力也越大 ,颅内动脉瘤的生长和破裂一般发生在这里 ;血液脉动使得远端壁面剪应力随时间的波动更加剧烈 ,颅内动脉瘤在这一区域更易破裂 ;此外 ,管径减小而流速不变 ,动脉瘤远端壁面剪应力增大 ,这说明在小血管中比大血管中更容易发生动脉瘤 ,这一结果与生理实际一致。

Hemodynamics of intracranial lateral aneurysms was simulated numerically.The blood was considered as Newtonian fluid and the elasticity of the wall was neglected.Three-dimension N-S equations were solved by using artificial compressibility algorithm.The influence of aneurysmal geometry shape and Reynolds number on hemodynamic factors,such as shear stress on the wall,pressure were calculated in the static and pulsatile conditions.The main results were that the greater depth of intracranial aneurysm,the greater distal shear stress is in which the aneurysm grow up and rupture for the intracranial aneurysms in the early stage in both static and pulsatile conditions;the pulsatile make the variety of distal shear stress with space and time more violent and easier rupture.The distal shear stress of aneurysm increases while the arterial diameter decrease and the velocity keep constant.It shows that the intracranial aneurysm is easier grow in small artery than that in the bigger blood tube.This result is consistent with physiology.