Department of Neurosurgery, Mie Chuo Medical Center, Tsu, Japan.
Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Japan.
J Neurointerv Surg. 2019 Jun;11(6):614-617. doi: 10.1136/neurintsurg-2018-014489. Epub 2019 Jan 22.
Complex and unstable flow patterns are reported to be associated with the rupture status of cerebral aneurysms, while their evaluation depends on qualitative analysis of streamlines of bloodflow. Oscillatory velocity index (OVI) is a hemodynamic parameter to quantify flow patterns. The aim of this study is to elucidate the associations between OVI and the rupture status of cerebral aneurysms.
One hundred and twenty-nine ruptured and unruptured cerebral aneurysms were analyzed with computational fluid dynamics under pulsatile flow conditions. With the use of median value of OVI, all aneurysms were divided into high and low OVI groups. Statistical analysis was performed to compare rupture status, and morphological and hemodynamic parameters between the two groups.
The median value of OVI was 0.006. High OVI was more likely observed in ruptured aneurysms (P=0.028) and associated with irregular shape, complex flow patterns, and unstable flow patterns (P<0.001, respectively). In morphological parameters, maximum size, aspect, projection, size, and volume-to-ostium area ratios were significantly higher in the high OVI group (P<0.001, respectively). In hemodynamic parameters, wall shear stress and wall shear stress gradient were significantly lower, and oscillatory shear index and gradient oscillatory number were significantly higher in the high OVI group (P<0.001, respectively).
High OVI was associated with rupture status, and morphological and hemodynamic characteristics of ruptured aneurysms. These results indicate that OVI may serve as a valuable hemodynamic parameter for diagnosing rupture status and risks of aneurysms.
据报道，复杂且不稳定的血流模式与脑动脉瘤的破裂状态有关，而其评估取决于血流流线的定性分析。振荡速度指数（OVI）是量化血流模式的一个血流动力学参数。本研究旨在阐明 OVI 与脑动脉瘤破裂状态之间的关系。
在脉动流条件下，对 129 个破裂和未破裂的脑动脉瘤进行了计算流体动力学分析。使用 OVI 的中位数，将所有动脉瘤分为高 OVI 和低 OVI 组。进行统计学分析，比较两组之间的破裂状态、形态和血流动力学参数。
OVI 的中位数为 0.006。高 OVI 更可能出现在破裂的动脉瘤中（P=0.028），与不规则形状、复杂血流模式和不稳定血流模式相关（分别为 P<0.001）。在形态学参数中，最大尺寸、形状、投影、尺寸和体积与口面积比在高 OVI 组中显著更高（分别为 P<0.001）。在血流动力学参数中，壁面切应力和壁面切应力梯度显著降低，而高 OVI 组的振荡剪切指数和梯度振荡数显著升高（分别为 P<0.001）。
高 OVI 与破裂状态以及破裂动脉瘤的形态和血流动力学特征相关。这些结果表明，OVI 可能是诊断破裂状态和动脉瘤风险的有价值的血流动力学参数。
