颅内直母管动脉旁瘤在线圈栓塞后三维脉动流的数值模拟

Numerical Simulation of Three-Dimensional Pulsatile Flow after Coil Embolization of a Lateral Aneurysm with a Straight Parent Vessel

对部分栓塞的不同线圈位置的血液流动进行数值模拟,以建议线圈栓塞的有效位置。在血液为不可压缩、牛顿流体和刚性血管假定下,利用人工压缩性方法求解三维N-S方程。在脉动情况下,计算了沿肿瘤壁面的平均剪应力、入流率、速度场和压力场。基于管径的最大/最小Reynolds数是475/152,Womersley数是2.5,这些值表示了中等脑动脉。主要的结果是:与无栓塞情况比较,栓塞后的壁面平均剪应力、入流率、瘤中速度和压力显著地减小;在瘤颈近端或远端被栓塞后的壁面平均剪应力和流入率都比瘤的顶部被栓塞后的小,而近端被栓塞后的壁面平均剪应力和流入率最小。既然小的入流率和低的剪应力提供了促使血栓形成的环境,那么近端或远端瘤颈应该是线圈栓塞最合适的位置。

Blood flow characteristics which are affected by the locations of coil for partially blocked aneurysm for a lateral aneurysm with a straight parent vessel is numerically simulated in order to find the coil locations effective for aneurysm embolization. Supposing blood incompressible, viscous, Newtonian flow, non-elasticity of the wall, three-dimensional N-S equations are solved using artificial compressibility algorithm at pulsatile conditions. The maximum /minimum Reynolds number is set at about 475/152 based on diameter of parent vessel. The Womersley number is set to 2.5. These values are representative of the middle cerebral arteries in vivo data. The velocity, pressure field, mean wall shear stress on the aneurysm and inflow rate are calculated. The results show that velocity, pressure in aneurysm sac, mean shear stress on the aneurysm and inflow rate reduce greatly in the blocked model as compared to the non-blocked model. Inflow rate and mean wall shear stress in the neck blocked models are much lower than that in the dome blocked model and the lowest in the proximal neck blocked model. Since lower wall shear stress and smaller inflow provide hemodynamic environment promoting blood cloting, proximal or distal neck should be the effective coil location for a giant aneurysm embolization.