中文摘要：

目的探讨颅内分叶状动脉瘤的血流动力学特点。方法结合DSA三维图像,采用计算流体力学（CFD）有限元方法的软件,对2个（动脉瘤1为侧壁动脉瘤,动脉瘤2为顶端动脉瘤）颅内分叶状动脉瘤的血流动力学进行数值模拟,观察动脉瘤内血流流动模式及血流动力学参数（流速、壁面切应力及压力）。结果①两个动脉瘤的分叶均位于入流动脉的血流高速冲击处和血流涡流处。②在1个心动周期内（0.1～0.8s）,两个分叶状动脉瘤的流速、壁面切应力及压力的最大值均出现在收缩期末的0.2s时刻。分叶状动脉瘤内从分叶发生处到分叶的深部出现了流速、壁面切应力及压力变化梯度,动脉瘤每个分叶的发生处数值最高,分叶的顶端数值最低（接近于0）。两个动脉瘤分叶发生处血流流速、壁面切应力、动压平均值分别为（1.20±0.40）m/s、（8.12±2.44）Pa、（851±508）Pa;分叶深部分别为（0.45±0.20）m/s、（0.64±0.27）Pa、（103±81）Pa,差异均有统计学意义（P〈0.01）。③动脉瘤内壁面切应力和动压变化与血流流速变化呈正相关（r=0.947,P=0.000;r=0.969,P=0.000）。结论颅内分叶状动脉瘤的形成与高速血流的冲击有关;分叶发生处的高流速、高压力、高壁面切应力,可能与分叶的发生和生长有关;分叶深部的低流速、低压力、低壁面切应力,可能与动脉瘤易破裂有关。

英文摘要：

Objective To explore the hemodynamic characteristics of lobulated intracranial aneurysms. Methods The software of computational fluid dynamics （CFD） finite element method was used to conduct numerical simulation of the hemodynamics for two lobulated intracranial aneurysms （ one was a side-wall aneurysm, and the other was a terminal aneurysm） in combination with the 3D DSA images. The blood flow patterns and hemodynamic parameters （ velocity, wall shear stress and pressure） in the aneurysms were observed. Results The two lobulated aneurysms were all occurred at the sites of the highspeed impact of inflow artery and vortex flow. The maximum values of the flow velocity, wall shear stress and pressure of the 2 lobulated aneurysms occurred during T = 0.2 s at the end-systolic phase in one cardiac cycle （0.1 to 0.8 s）. Within the lobulated aneurysms, from their bases to the tops, the velocity, wall shear stress and pressure gradient were occurred, the numerical value were highest at the base and lowest （close to 0） at the top. The average value of blood flow, wall shear stress and dynamic pressure at the bases of the two lobulated aneurysms were 1.20 ± 0. 40 m/s, 8.12± 2.44 Pa, and 851 ± 508 Pa, respectively ; at the tops of lobulated aneurysm were 0.45±0. 20 m/s, 0.64±0.27 Pa, and 103±81 Pa, respectively, and there were significant differences （ P 〈 0. 01 ）. The wall surface shear stress and dynamic pressure changes in the aneurysms were positively correlated with the blood flow velocity changes （r =0. 947, P =0. 000; r =0. 969, P = 0. 000）. Conclusions The formation of lobulated aneurysm is associated with the impact of high-speed flow; the high velocity, high pressure and high wall shear stress at the base of lobulated aneurysms may be associated with the development and growth of the lobulated aneurysm; and the low-velocity, low pressure and low wall shear stress at the tops of lobulated aneurysm may be associated with rupture-prone of the aneurysms.