From the Departments of Neurosurgery (Z.H., M.Z., F.H.C., W.G.T.).
Radiology (F.Y.Z., C.Q.C.), Xiangya Hospital, Central South University, Changsha, China.
AJNR Am J Neuroradiol. 2020 Jul;41(7):1217-1224. doi: 10.3174/ajnr.A6615. Epub 2020 Jun 18.
Previous studies have reported that MCA bifurcation aneurysms usually emerge on inclined bifurcations; however, the reason is unclear. We designed this study to explore hemodynamic mechanisms that correlate with the initiation of MCA bifurcation aneurysms.
Fifty-four patients with unilateral MCA bifurcation aneurysms and 54 control patients were enrolled in this study after propensity score matching, and their clinical and CTA data were collected. We extracted the morphologic features of aneurysmal MCA bifurcations to build a simplified MCA bifurcation model and performed a computational fluid dynamics analysis.
The presence of MCA aneurysms correlated with smaller parent-daughter angles of MCA bifurcations (< .001). Aneurysmal MCA bifurcations usually presented with inclined shapes. The computational fluid dynamics analysis demonstrated that when arterial bifurcations became inclined, the high-pressure regions and low wall shear stress regions shifted from the apexes of the arterial bifurcations to the inclined daughter arteries, while the initial sites of MCA bifurcation aneurysms often overlapped with the shifted high-pressure regions and low wall shear stress regions.
Our results suggest that the initiation of MCA bifurcation aneurysms may correlate with shifts of high-pressure regions and low wall shear stress regions that occur on inclined MCA bifurcations.
既往研究报道 MCA 分叉部动脉瘤通常出现在倾斜分叉部；然而，其原因尚不清楚。我们设计了本研究，旨在探讨与 MCA 分叉部动脉瘤起始相关的血流动力学机制。
本研究经倾向性评分匹配纳入了 54 例单侧 MCA 分叉部动脉瘤患者和 54 例对照患者，并收集了他们的临床和 CTA 数据。我们提取了动脉瘤性 MCA 分叉部的形态特征，构建了简化的 MCA 分叉模型，并进行了计算流体动力学分析。
MCA 动脉瘤的存在与 MCA 分叉部较小的母-子角度相关（<.001）。动脉瘤性 MCA 分叉部通常呈倾斜状。计算流体动力学分析表明，当动脉分叉部倾斜时，高压区和低壁切应力区从动脉分叉部的顶点转移到倾斜的子动脉，而 MCA 分叉部动脉瘤的起始部位通常与转移的高压区和低壁切应力区重叠。
我们的结果表明，MCA 分叉部动脉瘤的起始可能与倾斜 MCA 分叉部上高压区和低壁切应力区的转移相关。
