Mechanical Engineering Department, College of Engineering and Technology, Arab Academy for Science, Technology and Maritime Transport (AASTMT), Alexandria, Egypt.
Proc Inst Mech Eng H. 2020 Jul;234(7):711-719. doi: 10.1177/0954411920917531. Epub 2020 May 19.
Cerebral aneurysm is a fatal neurovascular disorder. Computational fluid dynamics simulation of aneurysm haemodynamics is one of the most important research tools which provide increasing potential for clinical applications. However, computational fluid dynamics modelling of such delicate neurovascular disorder involves physical complexities that cannot be easily simplified. Recently, it was shown that the Newtonian simplification used to close the shear stress tensor of the Navier-Stokes equation is not sufficient to explore aneurysm haemodynamics. This article explores the differences between the latter simplification, non-Newtonian power-law model and a newly proposed quasi-mechanistic model. The modified Krieger model, which treats blood as a suspension of plasma and particles, was implemented in computational fluid dynamics context here for the first time and is made available to the readers in a C# code in the supplementary material of this article. Two middle-cerebral artery and two anterior-communicating artery aneurysms, all ruptured, were utilized here as case studies. It was shown that the modified Krieger model had higher sensitivity for wall shear stress calculations in comparison with the other two models. The modified Krieger model yielded lower wall shear stress values consistently in comparison with the other two models. Moreover, the modified Krieger model has generally predicted higher pressure in the aneurysm models. Based on published aneurysm rupture studies, it is believed that ruptured aneurysms are usually correlated with lower wall shear stress values than unruptured ones. Therefore, this work concludes that the modified Krieger model is a potential candidate for providing better clinical relevance to aneurysm computational fluid dynamics simulations.
颅内动脉瘤是一种致命的神经血管疾病。对动脉瘤血流动力学进行计算流体动力学模拟是最重要的研究工具之一，为临床应用提供了越来越大的潜力。然而，对如此精细的神经血管疾病进行计算流体动力学建模涉及到无法轻易简化的物理复杂性。最近，有人指出，用于封闭纳维-斯托克斯方程的剪切应力张量的牛顿简化不足以探索动脉瘤血流动力学。本文探讨了后者简化、非牛顿幂律模型和新提出的拟力学模型之间的差异。在这里，首次在计算流体动力学环境中实现了修正的克里格模型，该模型将血液视为血浆和颗粒的悬浮液，并在本文的补充材料中以 C#代码的形式提供给读者。利用两个大脑中动脉和两个前交通动脉动脉瘤（均已破裂）作为病例研究。结果表明，与其他两种模型相比，修正的克里格模型在计算壁面剪切应力方面具有更高的灵敏度。与其他两种模型相比，修正的克里格模型始终产生较低的壁面剪切应力值。此外，修正的克里格模型通常预测动脉瘤模型中的压力更高。根据已发表的动脉瘤破裂研究，破裂的动脉瘤通常与未破裂的动脉瘤相比，壁面剪切应力值较低有关。因此，这项工作的结论是，修正的克里格模型是为动脉瘤计算流体动力学模拟提供更好临床相关性的潜在候选者。
