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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。
Objective To investigate the hemodynamic characteristics of intracranial lobulated aneurysms. Methods Combined with the DSA three-dimensional images and the software of Computational Fluid Dynamics (CFD) finite element method, the blood flow of two intracranial lobular aneurysms (aneurysm 1, aneurysm 2 and apical aneurysm 2) Dynamic simulation was performed to observe the flow pattern and hemodynamic parameters (flow rate, wall shear stress and pressure) within the aneurysm. Results ① The two aneurysm lobes are located in the inflow of high-speed impact of blood flow and blood flow at the vortex. ② In one cardiac cycle (0.1 ~ 0.8s), the maximal flow velocity, wall shear stress and pressure of two lobulated aneurysms occurred at 0.2s at the end of systole. There were flow velocity, wall shear stress and pressure gradient in the segmental aneurysm from the leaflet to the deep leaf. The highest incidence of each leaflet in the aneurysm and the lowest leaflet tip (close to 0 ). The average flow velocity, wall shear stress and dynamic pressure of the two aneurysms were (1.20 ± 0.40) m / s, (8.12 ± 2.44) Pa and (851 ± 508) Pa, respectively (0.45 ± 0.20) m / s, (0.64 ± 0.27) Pa and (103 ± 81) Pa, respectively. The difference was statistically significant (P <0.01). The changes of aneurysm wall shear stress and dynamic pressure were positively correlated with the changes of blood flow velocity (r = 0.947, P = 0.000; r = 0.969, P = 0.000). Conclusions The formation of intracranial aneurysm is related to the impact of high-speed blood flow. The high flow rate, high pressure and high wall shear stress at the location of the branch may be related to the occurrence and growth of the branch. The low flow rate , Low pressure, low wall shear stress, may be related to aneurysm rupture.