Varble Nicole, Trylesinski Gabriel, Xiang Jianping, Snyder Kenneth, Meng Hui
Department of Mechanical and Aerospace Engineering, University at Buffalo, State University of New York, Buffalo, NY, USA.
Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY, USA.
J R Soc Interface. 2017 May;14(130). doi: 10.1098/rsif.2017.0021.
An intracranial aneurysm (IA) is a cerebrovascular pathology that can lead to death or disability if ruptured. Abnormal wall shear stress (WSS) has been associated with IA growth and rupture, but little is known about the underlying flow physics related to rupture-prone IAs. Previous studies, based on analysis of a few aneurysms or partial views of three-dimensional vortex structures, suggest that rupture is associated with complex vortical flow inside IAs. To further elucidate the relevance of vortical flow in aneurysm pathophysiology, we studied 204 patient IAs (56 ruptured and 148 unruptured). Using objective quantities to identify three-dimensional vortex structures, we investigated the characteristics associated with aneurysm rupture and if these features correlate with previously proposed WSS and morphological characteristics indicative of IA rupture. Based on the -criterion definition of a vortex, we quantified the degree of the aneurysmal region occupied by vortex structures using the volume vortex fraction () and the surface vortex fraction (). Computational fluid dynamics simulations showed that the , but not the , discriminated ruptured from unruptured aneurysms. Furthermore, we found that the near-wall vortex structures co-localized with regions of inflow jet breakdown, and significantly correlated to previously proposed haemodynamic and morphologic characteristics of ruptured IAs.
颅内动脉瘤（IA）是一种脑血管病变，破裂时可导致死亡或残疾。异常的壁面剪应力（WSS）与IA的生长和破裂有关，但对于与易破裂IA相关的潜在流动物理学知之甚少。以往的研究基于对少数动脉瘤的分析或三维涡旋结构的局部视图，表明破裂与IA内部复杂的涡旋流动有关。为了进一步阐明涡旋流动在动脉瘤病理生理学中的相关性，我们研究了204例患者的IA（56例破裂，148例未破裂）。我们使用客观量来识别三维涡旋结构，研究了与动脉瘤破裂相关的特征，以及这些特征是否与先前提出的指示IA破裂的WSS和形态特征相关。基于涡旋的 - 准则定义，我们使用体积涡旋分数（）和表面涡旋分数（）量化了涡旋结构占据的动脉瘤区域的程度。计算流体动力学模拟表明，能够区分破裂和未破裂的动脉瘤，而不能。此外，我们发现近壁涡旋结构与流入射流破裂区域共定位，并且与先前提出的破裂IA的血流动力学和形态特征显著相关。
