Analysis of hemodynamics and wall mechanics at sites of cerebral aneurysm rupture
Analysis of hemodynamics and wall mechanics at sites of cerebral aneurysm rupture
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DOI：
10.1136/neurintsurg-2014-011247
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发表时间：
2015-07-01
影响因子：
4.8
通讯作者：
Putman, Christopher M.
中科院分区：
文献类型：
--
作者：
Cebral, Juan R.;Vazquez, Mariano;Putman, Christopher M.
研究背景动脉瘤的形成是动脉瘤壁在高或低的壁切应力（WSS）的异常血流动力学作用下逐渐退化的结果目的探讨这两种不同的血流动力学途径在一系列破裂部位已知的脑动脉瘤中的作用。通过计算流体动力学（CFD）模拟获得WSS分布。在CFD模型确定的血流动力学载荷下，使用结构壁模型计算内壁应力。用WSS分布（在高或低WSS区域增加或减少）调节壁特性（厚度和刚度），以测试可能的壁降解途径。破裂概率指数（RPI）计算比较不同的壁models.Results大多数破裂部位对齐的囊内流和下游的主要冲击区。最能解释9个动脉瘤中8个（89%）破裂部位（产生更高RPI）的模型在异常高WSS区域具有更薄和更硬的壁。剩余的情况下（11%）是最好的解释了一个模型，在异常低WSS.Conclusions动脉瘤破裂的区域更薄，更硬的墙壁似乎是由局部退化和弱化的壁异常血流动力学。基于图像的计算模型假设壁变薄和硬化异常高的WSS区域能够解释大多数观察到的破裂部位。
Background It is thought that aneurysms evolve as the result of progressive degradation of the wall in response to abnormal hemodynamics characterized by either high or low wall shear stress (WSS).Objective To investigate the effects of these two different hemodynamic pathways in a series of cerebral aneurysms with known rupture sites.Methods Nine aneurysms in which the rupture site could be identified in three-dimensional images were analyzed. The WSS distribution was obtained from computational fluid dynamics (CFD) simulations. Internal wall stresses were computed using structural wall models under hemodynamic loads determined by the CFD models. Wall properties (thickness and stiffness) were modulated with the WSS distribution (increased or decreased in regions of high or low WSS) to test possible wall degradation pathways. Rupture probability indices (RPI) were calculated to compare different wall models.Results Most rupture sites aligned with the intrasaccular flow stream and downstream of the primary impaction zone. The model that best explained the rupture site (produced higher RPI) in eight of the nine aneurysms (89%) had thinner and stiffer walls in regions of abnormally high WSS. The remaining case (11%) was best explained by a model with thinner and stiffer walls in regions of abnormally low WSS.Conclusions Aneurysm rupture seems to be caused by localized degradation and weakening of the wall in response to abnormal hemodynamics. Image-based computational models assuming wall thinning and stiffening in regions of abnormally high WSS were able to explain most of the observed rupture sites.