Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.
Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
Invest Ophthalmol Vis Sci. 2019 Jun 3;60(7):2773-2780. doi: 10.1167/iovs.19-26997.
Explore in vivo whether there is direct communication between the cerebrospinal fluid (CSF) and extravascular compartment of human visual pathway structures.
A prospective and observational study included 10 subjects who underwent intrathecal gadolinium-enhanced magnetic resonance imaging (MRI) for suspected CSF circulation disorder, but with a negative result and with no known ophthalmic diseases. After precontrast T1-weighted MRI, 0.5 mL of gadobutrol (Gadovist, 1.0 mmol/mL) was injected intrathecally. Gadobutrol distributes in the extravascular space, and served as a CSF tracer. Consecutive MRI scans were obtained throughout 24 to 48 hours. To assess gadobutrol contrast enrichment, regions of interest (ROIs) were placed at multiple locations along the visual pathway, from the primary visual cortex to the eye's vitreous body. CSF tracer dependent T1 signal was measured in each ROI. A linear mixed-model was used for statistical analyses.
CSF tracer enrichment was found within the optic nerve, optic chiasm, optic tract, and primary visual cortex (P < 0.001). Peak tracer enrichment in the visual pathway generally occurred after 24 hours and was preceded by peak enhancement in the prechiasmatic cistern after 4 to 6 hours.
The results indicate direct communication between CSF of subarachnoid space and the extravascular space of the human visual pathway. Extravascular entry of the CSF tracer is a prerequisite for a glymphatic system, the present findings may suggest its presence. The existence of a glymphatic system in the human visual pathway could bring novel perspectives on the pathophysiology and treatment of ophthalmic diseases.
在体内探索人视觉通路结构的脑脊液（CSF）与血管外腔之间是否存在直接通讯。
本前瞻性观察性研究纳入了 10 名接受鞘内钆增强磁共振成像（MRI）检查的疑似 CSF 循环障碍患者，但检查结果为阴性且无已知眼部疾病。在预对比 T1 加权 MRI 后，经鞘内注射 0.5 毫升钆布醇（Gadovist，1.0mmol/mL）。钆布醇分布在血管外间隙，作为 CSF 示踪剂。在 24 至 48 小时内连续进行 MRI 扫描。为了评估钆布醇对比剂的富集情况，在视觉通路上的多个部位（从初级视皮层到眼球玻璃体）放置感兴趣区（ROI）。在每个 ROI 中测量 CSF 示踪剂依赖的 T1 信号。使用线性混合模型进行统计分析。
在视神经、视交叉、视束和初级视皮层中发现 CSF 示踪剂富集（P<0.001）。视觉通路上的示踪剂富集峰值通常发生在 24 小时后，在 4 至 6 小时前出现视交叉前池的增强峰值。
这些结果表明 CSF 与人类视觉通路的血管外腔之间存在直接通讯。CSF 示踪剂的血管外进入是其存在的前提条件，即血-脑屏障外液系统。血-脑屏障外液系统在人类视觉通路上的存在可能为眼部疾病的病理生理学和治疗带来新的视角。
