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Abstract：
Hemodynamics in intracranial aneurysm strongly depends on the non-Newtonian blood behavior due to the large number of suspended cells and the ability of red blood cells to deform and aggregate. However, most numerical investigations on intracranial hemodynamics adopt the Newtonian hypothesis to model blood flow and predict aneurysm occlusion. The aim of this study was to analyze the effect of the blood rheological model on the hemodynamics of intracranial aneurysms in the presence or absence of endovascular treatment. A numerical investigation was performed under pulsatile flow conditions in a patient-specific aneurysm with and without the insertion of an appropriately reconstructed flow diverter stent (FDS). The numerical simulations were performed using Newtonian and non-Newtonian assumptions for blood rheology. In all cases, FDS placement reduced the intra-aneurysmal velocity and increased the relative residence time (RRT) on the aneurysmal wall, indicating progressive thrombus formation and aneurysm occlusion. However, the Newtonian model largely overestimated RRT values and consequent aneurysm healing with respect to the non-Newtonian models. Due to the non-Newtonian blood properties and the large discrepancy between Newtonian and non-Newtonian simulations, the Newtonian hypothesis should not be used in the study of the hemodynamics of intracranial aneurysm, especially in the presence of endovascular treatment.
摘要：
由于大量的悬浮细胞以及红细胞变形和聚集的能力，颅内动脉瘤的血液动力学在很大程度上取决于非牛顿血液行为。然而,大多数颅内血流动力学的数值研究采用牛顿假说来模拟血流并预测动脉瘤闭塞.这项研究的目的是分析在存在或不存在血管内治疗的情况下，血液流变学模型对颅内动脉瘤血流动力学的影响。在有或没有插入适当重建的分流器支架（FDS）的情况下，在患者特定动脉瘤的脉动流条件下进行了数值研究。使用血液流变学的牛顿和非牛顿假设进行数值模拟。在所有情况下,FDS放置降低了动脉瘤内速度并增加了在动脉瘤壁上的相对停留时间（RRT），提示进行性血栓形成和动脉瘤闭塞。然而,相对于非牛顿模型，牛顿模型大大高估了RRT值和随后的动脉瘤愈合。由于非牛顿血液特性以及牛顿与非牛顿模拟之间的巨大差异，牛顿假说不应用于颅内动脉瘤的血流动力学研究,尤其是在血管内治疗的情况下。
