Byun Hong Sik, Rhee Kyehan
Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Med Eng Phys. 2004 Nov;26(9):755-61. doi: 10.1016/j.medengphy.2004.06.008.
In case of coil embolization of a giant or a multilobular aneurysm, it is difficult to fill an aneurysm sac completely with coils, therefore, partial blocking of an aneurysm sac is inevitable. Blood flow characteristics, which may influence embolization process of an aneurysm, are affected by the locations of coils for partially blocked aneurysms. Blood flow fields inside an aneurysm are also influenced by the geometry of a parent vessel. In order to suggest the coil locations effective for aneurysm embolization, the blood flow fields of lateral aneurysm models were analyzed for different coil locations and parent vessel geometries. Flow rate into an aneurysm sac from a parent vessel (inflow rate) and wall shear stress were also calculated. Inflow rates were smaller and low wall shear regions were larger in the distal neck blocked model comparing to the dome blocked models. In the distal neck blocked model, inflow volume was smaller by 31% (straight parent vessel model) and 34% (curved parent vessel model) comparing to other models. The time averaged values of normalized low wall shear regions were 4% and 12% greater in the distal neck blocked models with a straight and a curved parent vessel, respectively. Since smaller inflow and low wall shear stress provide hemodynamic environment promoting thrombus embolization, distal neck should be the effective coil location for aneurysm embolization.
对于巨大或多叶状动脉瘤进行弹簧圈栓塞时，很难用弹簧圈完全填满动脉瘤囊，因此，动脉瘤囊的部分阻塞不可避免。可能影响动脉瘤栓塞过程的血流特性，会受到部分阻塞动脉瘤的弹簧圈位置的影响。动脉瘤内部的血流场也会受到母血管几何形状的影响。为了提出对动脉瘤栓塞有效的弹簧圈位置，针对不同的弹簧圈位置和母血管几何形状，分析了侧面动脉瘤模型的血流场。还计算了从母血管流入动脉瘤囊的流速（流入速率）和壁面剪应力。与瘤顶阻塞模型相比，远端颈部阻塞模型中从母血管流入动脉瘤囊的流速较小，低壁面剪应力区域较大。在远端颈部阻塞模型中，与其他模型相比，流入量分别减少了31%（直母血管模型）和34%（弯曲母血管模型）。在具有直母血管和弯曲母血管的远端颈部阻塞模型中，归一化低壁面剪应力区域的时间平均值分别高出4%和12%。由于较小的流入量和低壁面剪应力提供了促进血栓栓塞的血流动力学环境，因此远端颈部应是动脉瘤栓塞的有效弹簧圈放置位置。
