上矢状窦旁桥静脉的解剖及其血流动力学数值模拟

目的 通过对上矢状窦旁桥静脉的血流动力学数值模拟，为脑静脉血栓形成发病机制的解释和影像学诊断提供形态学证据。方法 对6例（12侧）上矢状窦和颈内静脉灌注蓝色乳胶的成人头颅湿标本进行观测，测量各支桥静脉的直径及其注入上矢状窦的角度；利用解剖数据，应用计算流体力学分析软件Fluent，建立上矢状窦旁桥静脉的血流动力学模型，对不同模型的壁面剪切力进行比较分析。结果 上矢状窦旁桥静脉共计137支，分为前后两组，其中后组桥静脉的直径较大，注入上矢状窦的角度较小。共建立模型137个，桥静脉直径>1.2mm、65°≤注入角度<105°时，注入处下游上矢状窦壁壁面剪切力下降明显；桥静脉直径>1.2 mm、注入角度<65°时，注入处下游上矢状窦壁和注入处上游桥静脉壁壁面剪切力下降明显，桥静脉壁壁面剪切力最低值为上矢状窦壁上的63%。与前段组桥静脉模型相比较，后段组模型上矢状窦壁和桥静脉壁壁面剪切力最低值较小，距注入处较远。结论 桥静脉直径>1.2mm，且注入角度<65°时，血管壁面剪切力急剧下降，脑静脉血栓形成容易发生。血栓好发于上矢状窦后段的注入处上游桥静脉壁。

Microanatomy and hemodynamic numerical simulation of the cerebral bridging veins entering superior sagittal sinus

Objective To simulate the hemodynamic feature in cerebral bridging veins (BVs), in order to provide a morphologic basis for the pathogenesis explanation and imaging diagnosis of cerebral venous thrombosis (CVT). Methods Totally 6 human cadavers (12 sides) were examined in this study. Each head of the cadavers was injected with blue-coloured latex via the superior sagittal sinus (SSS) and internal jugular veins. The diamter and the angle of BVs entering SSS were measured. Based on the data of cadavers and computational fluid dynamics software pack, the hemodynamic models were established. The wall shear stress (WSS) was carefully studied and compared between different models. Results The total of 137 BVs formed two clusters along the SSS: anterior group and posterior group. Compared with anterior group BVs, the diameter of posterior group BVs was large, and the angle was smaller. In 137 models,when the diameter of a BV was more than 1.2mm, and the angle was between 65 and 105 degree, the local WSS decreased in the downstream wall of SSS. When the diameter of a BV was more than 1.2mm, and the angle was less than 65 degree, the local WSS decreased in the downstream wall of SSS and the upstream wall of BVs. The minimum WSS in BVs was 63% of the minimum WSS in SSS. Compared with the anterior group BVs, the minimum WSS in the wall of posterior group BVs was samller, and the distance from the minimum WSS to the dural entrance was longer. Conclusion CVT occurs easily when the diamter of a BV is more than 1.2mm and the angle is less than 65 degree. The embolus forms early in the upstream wall of BVs entering the posterior part of SSS.