Flow Instability Detected by High-Resolution Computational Fluid Dynamics in Fifty-Six Middle Cerebral Artery Aneurysms.
Flow Instability Detected by High-Resolution Computational Fluid Dynamics in Fifty-Six Middle Cerebral Artery Aneurysms.
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通过高分辨率计算流体动力学检测 56 个大脑中动脉动脉瘤的血流不稳定性。
DOI：
10.1115/1.4033477
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Meng,Hui
中科院分区：
文献类型：
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作者：
Varble,Nicole;Xiang,Jianping;Lin,Ning;Levy,Elad;Meng,Hui
最近的高分辨率计算流体动力学(CFD)研究发现了颅内动脉瘤(IAS)中持续的血流不稳定，这在以前的硅胶研究中是没有观察到的。在一个小的动脉瘤数据集中，这些血流波动与破裂是偶然相关的。这项研究的目的是探索商业cfdsolver捕捉这种速度波动的能力和局限性，波动动能(FKE)作为量化这种不稳定性的标志是否可以成为预测动脉瘤破裂的潜在参数，以及哪些几何参数可能与这种波动相关。首先，我们确认需要二阶离散化格式和高的空间和时间分辨率来捕捉这些动脉瘤状血流波动。接下来，我们分析了56个特定于患者的大脑中动脉(MCA)动脉瘤(12个破裂)，在循环平均、恒定流入边界条件下进行了瞬时、高分辨率的CFD模拟。最后，为了探索这种血流不稳定性可能产生的机制，我们研究了KE与几个动脉瘤几何参数之间的相关性。结果显示，56个大脑中动脉动脉瘤中有8个存在血流不稳定，均为未破裂的分叉动脉瘤。统计学分析显示，fKE不能区分破裂与未破裂的动脉瘤。因此，我们的研究不支持这些流动不稳定性(基于周期平均的恒定流入，而不是峰值速度)作为破裂的标志。我们发现KE与动脉瘤大小及大小比率呈正相关。这表明，固有的血流不稳定性可能与穿透动脉瘤腔的流入射流的破裂有关。
Recent high-resolution computational fluid dynamics (CFD) studies have detected persistent flow instability in intracranial aneurysms (IAs) that was not observed in previous in silico studies. These flow fluctuations have shown incidental association with rupture in a small aneurysm dataset. The aims of this study are to explore the capabilities and limitations of a commercialcfdsolver in capturing such velocity fluctuations, whether fluctuation kinetic energy (fKE) as a marker to quantify such instability could be a potential parameter to predict aneurysm rupture, and what geometric parameters might be associated with such fluctuations. First, we confirmed that the second-order discretization schemes and high spatial and temporal resolutions are required to capture these aneurysmal flow fluctuations. Next, we analyzed 56 patient-specific middle cerebral artery (MCA) aneurysms (12 ruptured) by transient, high-resolution CFD simulations with a cycle-averaged, constant inflow boundary condition. Finally, to explore the mechanism by which such flow instabilities might arise, we investigated correlations betweenfKEand several aneurysm geometrical parameters. Our results show that flow instabilities were present in 8 of 56 MCA aneurysms, all of which were unruptured bifurcation aneurysms. Statistical analysis revealed thatfKEcould not differentiate ruptured from unruptured aneurysms. Thus, our study does not lend support to these flow instabilities (based on a cycle-averaged constant inflow as opposed to peak velocity) being a marker for rupture. We found a positive correlation betweenfKEand aneurysm size as well as size ratio. This suggests that the intrinsic flow instability may be associated with the breakdown of an inflow jet penetrating the aneurysm space.