Flow instability and wall shear stress variation in intracranial aneurysms
Flow instability and wall shear stress variation in intracranial aneurysms
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DOI：
10.1098/rsif.2009.0476
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发表时间：
2010-06-06
影响因子：
3.9
通讯作者：
Karniadakis, G. E.
中科院分区：
文献类型：
--
作者：
Baek, H.;Jayaraman, M. V.;Karniadakis, G. E.
我们使用高分辨率数值模拟研究颅内动脉瘤中壁剪切应力（WSS）矢量的流动动力学和振荡行为。我们分析了三种具有代表性的患者特异性颈内动脉，其中充满了不同特征的动脉瘤：（i）宽颈囊状动脉瘤，（ii）窄颈囊状动脉瘤，以及（iii）具有两个相邻囊状动脉瘤的病例。我们的模拟表明，动脉瘤中的脉动流在减速收缩期期间可能会受到流体动力学不稳定的影响，导致 20-50 Hz 范围内的高频振荡，即使在情况 (iii) 和 (i) 中载瘤血管中的血流量分别低至 150 和 250 ml min(-1) 时也是如此。在舒张末期附近，血流恢复到其原始的层流脉动状态。当动脉瘤血流变得不稳定时，WSS矢量的大小和方向都会以上述高频波动。特别是，流动冲击区域周围的 WSS 矢量在方向和幅度上表现出显着的时空变化。
We investigate the flow dynamics and oscillatory behaviour of wall shear stress (WSS) vectors in intracranial aneurysms using high resolution numerical simulations. We analyse three representative patient-specific internal carotid arteries laden with aneurysms of different characteristics: (i) a wide-necked saccular aneurysm, (ii) a narrower-necked saccular aneurysm, and (iii) a case with two adjacent saccular aneurysms. Our simulations show that the pulsatile flow in aneurysms can be subject to a hydrodynamic instability during the decelerating systolic phase resulting in a high-frequency oscillation in the range of 20-50 Hz, even when the blood flow rate in the parent vessel is as low as 150 and 250 ml min(-1) for cases (iii) and (i), respectively. The flow returns to its original laminar pulsatile state near the end of diastole. When the aneurysmal flow becomes unstable, both the magnitude and the directions of WSS vectors fluctuate at the aforementioned high frequencies. In particular, the WSS vectors around the flow impingement region exhibit significant spatio-temporal changes in direction as well as in magnitude.