Variations in systemic properties of the arterial tree, such as aging-induced vessel stiffness, can alter the shape of pressure and flow waveforms. As a consequence, the hemodynamics around a cerebral aneurysm change, and therefore, also the corresponding in- and outlet boundary conditions (BCs) used for three-dimensional (3D) calculations of hemodynamic indices. In this study, we investigate the effects of variations in systemic properties on wall shear stress (WSS) indices of a cerebral aneurysm. We created a virtual patient database by varying systemic properties within physiological ranges. BCs for 3D-CFD simulations were derived using a pulse wave propagation model for each realization of the virtual database. WSS indices were derived from the 3D simulations and their variabilities quantified. Variations in BCs, caused by changes in systemic properties, yielded variabilities in the WSS indices that were of the same order of magnitude as differences in these WSS indices between ruptured and unruptured aneurysms. Sensitivity analysis showed that the systemic properties impacted both in- and outlet BCs simultaneously and altered the WSS indices. We conclude that the influence of variations in patient-specific systemic properties on WSS indices should be evaluated when using WSS indices in multidisciplinary rupture prediction models.

中文翻译：

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一维模型生成的受试者间变异对颅内动脉瘤壁剪切应力指数的全身特性的作用

动脉树系统特性的变化，例如老化引起的血管硬度，可以改变压力和流量波形的形状。因此，脑动脉瘤周围的血流动力学发生变化，因此用于血流动力学指数三维 (3D) 计算的相应入口和出口边界条件 (BC) 也会发生变化。在这项研究中，我们调查了全身特性变化对脑动脉瘤壁剪切应力 (WSS) 指数的影响。我们通过在生理范围内改变系统特性创建了一个虚拟患者数据库。用于 3D-CFD 模拟的 BC 是使用脉冲波传播模型为虚拟数据库的每个实现推导出来的。WSS 指数源自 3D 模拟及其量化的可变性。BC 的变化，由全身特性的变化引起的 WSS 指数的变异性与破裂和未破裂动脉瘤之间这些 WSS 指数的差异具有相同的数量级。敏感性分析表明，系统特性同时影响入口和出口 BC，并改变了 WSS 指数。我们得出的结论是，在多学科破裂预测模型中使用 WSS 指数时，应评估患者特定系统特性的变化对 WSS 指数的影响。