Kuo Phillip H, Stuehm Carol, Squire Scott, Johnson Kevin
Departments of Medical Imaging.
Medicine and Biomedical Engineering, University of Arizona, Tucson, AZ.
Tomography. 2018 Sep;4(3):99-104. doi: 10.18383/j.tom.2018.00013.
The recent report of the existence of meningeal lymphatic vessels (MLVs) in human and nonhuman primates used both histology and magnetic resonance imaging (MRI). Many questions about the physiology and function of these lymphatic vessels remain unanswered. Through the combination of appropriately positioned saturation bands and time-of-flight angiography sequences, MRI can resolve direction of flow within vessels without the use of exogenous contrast agent. Six healthy volunteers underwent high-resolution MRI of the MLVs running alongside the superior sagittal sinus to determine the direction of the lymphatic flow. In all subjects, the lymphatic flow was posterior to anterior, countercurrent to the direction of venous flow in the superior sagittal sinus and alongside the superior sagittal sinus. This flow strongly supports that a large proportion of the CNS lymphatic flow in humans is directed to the cribriform plate. The countercurrent direction of flow in the MLVs relative to venous flow in the superior sagittal sinus has implications for modeling flow of fluid and solutes across the various compartments of the CNS. A hypothetical compartmental model incorporating countercurrent flow is presented here.
最近关于人类和非人类灵长类动物脑膜淋巴管（MLV）存在的报告同时使用了组织学和磁共振成像（MRI）。关于这些淋巴管的生理学和功能仍有许多问题未得到解答。通过适当位置的饱和带和飞行时间血管造影序列相结合，MRI无需使用外源性造影剂就能分辨血管内的血流方向。六名健康志愿者接受了沿上矢状窦走行的MLV的高分辨率MRI检查，以确定淋巴液流动的方向。在所有受试者中，淋巴液流动方向是从后向前，与上矢状窦内静脉血流方向相反且沿上矢状窦走行。这种流动有力地支持了人类中枢神经系统（CNS）大部分淋巴液流向筛板的观点。MLV中相对于上矢状窦内静脉血流的逆流方向对模拟液体和溶质在CNS各个腔室中的流动具有重要意义。本文提出了一个包含逆流的假设性腔室模型。
