中文摘要：

目的探讨大型未破裂颅内动脉瘤的血流动力学特点。方法结合数字减影血管造影（DSA）三维图像，采用计算流体力学（CFD）有限元方法的软件，对12例直径≥15mm的未破裂颅内动脉瘤进行数值模拟，对其血流动力学参数进行分析，并与其载瘤动脉上的参数相对比。结果大型动脉瘤内部涡流形态复杂，在主要涡流内部有大面积紊乱的低速流动。动脉瘤瘤颈处速度最大，瘤顶附近存在一个面积较大的低流速区，流速接近0；与其载瘤动脉相比，收缩期末平均壁面切应力（WSS）显著降低，平均切应力震荡因子（OSI）显著增高，瘤壁平均低WSS面积百分比为24．74％。结论未破裂大型动脉瘤的血流动力学特点为紊乱的涡流、瘤顶附近较大面积的低流速区、瘤壁高OSI和大面积的低wSS区。

英文摘要：

Objects To explore the hemodynamic factors in large unruptured intracranial saccular aneurysms. Methods The numerical simulation of hemodynamics in 12 patients with large size （those greater than 15 mm in diameter） unruptured intracranial saccular aneurysms were processed with software of finite element method of computational fluid dynamics （CFD） according to 3D-DSA images, and their hemodynamic factors were analyzed, the results were compared with that in the parent artery. Results The aneurysm neck displayed the highest flow velocity, and the dome displayed a large area of low flow region （close to 0）. Unstable flow patterns with large area of low flow vorteces were found in these aneurysms. The wall shear stress （WSS） was significantly lower and while the oscillatory shear index （OSI） higher in the aneurysms than those in the parent arteries. 24.74% of aneurysm area were under low WSS. Conclusions Intra-aneurismal unstable flow patterns, large area of low flow region in the dome, low WSS and high OSI in the aneurysms might be involved in increasing the risk of rupture for large unruptured intracranial saccular aneurysms.