顶端动脉瘤的血流动力学数值模拟速度分析

目的：探讨顶端动脉瘤的血流动力学特点，分析动脉瘤生长、破裂的可能机制。 方法：采用计算流体力学（CFD）软件结合顶端动脉瘤的医学影像，对动脉瘤内血液流动行 数值模拟。 结果：脉动状态下每个心动周期里，在0~0.4 s内速度变化最剧烈，在动脉分叉处形成涡运动。通过瘤颈进入动脉瘤内时，血流速度骤减，在动脉瘤中央形成涡，速度逐渐减小并可能静止。瘤顶血流速度很小甚至静止。 结论：顶端动脉瘤血流动力过程复杂，血管分叉处涡运动剧烈；瘤颈速度在0~0.5 s内剧烈变化，受到血流的冲击瘤颈扩大使瘤生长；破裂主要在瘤顶，但是瘤顶速度很小甚至静止，瘤壁在血流冲击下的振荡是破裂的因素之一。速度是危险因子之一，0~0.5 s是危险时间窗。

Hemodynamic numerical simulation and velocity analysis of intracranial terminal aneurysms

Objective To investigate the hemodynamic characteristics of intracranial terminal aneurysms and analysis the possible mechanism of growth and rupture of intracranial aneurysms. Methods Some images of intracranial terminal aneurysms were handled by some image processing software. The profile meshed by some computational fluid dynamics (CFD) software were used to simulate the flow. Results From the beginning to 0.4 s of every cardiac cycle, the velocity had a sharp change and vortex existed across the inlet in unsteady condition. The velocity decreased and came into be nearly stagnant when it acrossed the aneurysm neck and vortex came into being inside aneurysm. The velocity of the distal end of aneurysm was very slow and sometime its value was zero. Conclusion The hemodynamics of terminal aneurysms is very complex. The velocity in the neck has a sharp change and vortex exist during the period of 0-0.5 s. Under the impact of blood stream,the aneurysm neck begins to append and the aneurysm comcs to grow or rupture. It always happens in the distal end of aneurysm,but the velocity is very slow. Maybe the oscillation work was a risk factor for aneurysm rupture.