Department of Mechanical Engineering, College of Engineering, Nihon University, Koriyama, Japan.
Department of Neurosurgery, National Hospital Organization Kyoto Medical Center, Kyoto, Japan.
J Biomech. 2024 Nov;176:112355. doi: 10.1016/j.jbiomech.2024.112355. Epub 2024 Oct 1.
Although the hemodynamics of cerebral aneurysms have been extensively studied using patient-specific computational fluid dynamics techniques, no specific hemodynamic factors characteristic of cerebral aneurysm development have yet been identified. We believe that one problem with previous hemodynamic studies of cerebral aneurysms has been the manner in which control groups were created for comparison with experimental groups. The purpose of this study was to determine hemodynamic factors that correlated with the development of cerebral aneurysms. The control group was established in a manner that differed from those of previous works. This allowed us to demonstrate the effectiveness of our method. We artificially removed aneurysms in the middle cerebral artery bifurcations of nine patients and reconstructed the vessel geometries before the aneurysms had occurred. Pulsatile blood flow simulations were performed using the vessel geometries ipsilateral and contralateral to the sites of aneurysm removal, and hemodynamic metrics were calculated. Use of the ipsilateral and contralateral sides as the experimental and control sites, respectively, allowed us to evaluate statistically the hemodynamic metrics between the two corresponding sites/groups. The results showed that only the normalized transverse wall shear stress (NtransWSS) was significantly higher at the MCA bifurcation ipsilateral to the site of aneurysm removal than at the contralateral bifurcation (p = 0.01). There were no significant differences in the other hemodynamic metrics between the bilateral bifurcations. Our findings imply that multi-directional disturbed wall shear stress, which is detected by the NtransWSS metric, may be one hemodynamic risk factor for the development of cerebral aneurysms.
虽然使用患者特异性计算流体动力学技术已经广泛研究了脑动脉瘤的血液动力学，但尚未确定与脑动脉瘤发展相关的特定血液动力学因素。我们认为，以前脑动脉瘤血液动力学研究的一个问题是创建对照组以与实验组进行比较的方式。本研究旨在确定与脑动脉瘤发展相关的血液动力学因素。对照组的建立方式与以前的工作不同。这使我们能够证明我们的方法的有效性。我们人为地去除了 9 名患者大脑中动脉分叉处的动脉瘤，并在动脉瘤发生之前重建了血管几何形状。使用动脉瘤切除部位同侧和对侧的血管几何形状进行脉动血流模拟，并计算血液动力学指标。使用同侧和对侧作为实验和对照部位，我们可以分别评估两个相应部位/组之间的血液动力学指标的统计学差异。结果表明，仅在动脉瘤切除部位同侧的 MCA 分叉处的归一化横向壁切应力（NtransWSS）显著高于对侧分叉处（p = 0.01）。双侧分叉处的其他血液动力学指标没有显著差异。我们的研究结果表明，多方向的紊乱壁切应力，可由 NtransWSS 指标检测到，可能是脑动脉瘤发展的一个血液动力学危险因素。
