The glymphatic system is a recently discovered network unique to the central nervous system that allows for dynamic exchange of interstitial fluid (ISF) and cerebrospinal fluid (CSF). As detailed in part I, ISF and CSF transport along paravascular channels of the penetrating arteries and possibly veins allow essential clearance of neurotoxic solutes from the interstitium to the CSF efflux pathways. Imaging tests to investigate this neurophysiologic function, although challenging, are being developed and are reviewed herein. These include direct visualization of CSF transport using postcontrast imaging techniques following intravenous or intrathecal administration of contrast material and indirect glymphatic assessment with detection of enlarged perivascular spaces. Application of MRI techniques, including intravoxel incoherent motion, diffusion tensor imaging, and chemical exchange saturation transfer, is also discussed, as are methods for imaging dural lymphatic channels involved with CSF efflux. Subsequently, glymphatic function is considered in the context of proteinopathies associated with neurodegenerative diseases and traumatic brain injury, cytotoxic edema following acute ischemic stroke, and chronic hydrocephalus after subarachnoid hemorrhage. These examples highlight the substantial role of the glymphatic system in neurophysiology and the development of certain neuropathologic abnormalities, stressing the importance of its consideration when interpreting neuroimaging investigations.

© RSNA, 2021

淋巴系统是最近发现的中枢神经系统独有的网络，允许间质液 (ISF) 和脑脊液 (CSF) 的动态交换。如第一部分详述，ISF 和 CSF 沿着穿透动脉和可能的静脉的血管旁通道运输，允许从间质到 CSF 流出途径的神经毒性溶质的基本清除。研究这种神经生理功能的成像测试虽然具有挑战性，但正在开发中并在此进行审查。这些包括在静脉内或鞘内注射造影剂后使用造影后成像技术直接可视化脑脊液转运，以及通过检测扩大的血管周围间隙进行间接淋巴评估。MRI 技术的应用，包括体素内非相干运动，还讨论了扩散张量成像和化学交换饱和转移，以及对涉及 CSF 流出的硬脑膜淋巴通道进行成像的方法。随后，在与神经退行性疾病和创伤性脑损伤、急性缺血性中风后的细胞毒性水肿和蛛网膜下腔出血后的慢性脑积水相关的蛋白质病的背景下考虑了淋巴管功能。这些例子强调了淋巴系统在神经生理学和某些神经病理学异常的发展中的重要作用，强调了在解释神经影像学研究时考虑它的重要性。在与神经退行性疾病和外伤性脑损伤相关的蛋白质病、急性缺血性中风后的细胞毒性水肿和蛛网膜下腔出血后的慢性脑积水的背景下，考虑了 glymphatic 功能。这些例子强调了淋巴系统在神经生理学和某些神经病理学异常的发展中的重要作用，强调了在解释神经影像学研究时考虑它的重要性。在与神经退行性疾病和外伤性脑损伤相关的蛋白质病、急性缺血性中风后的细胞毒性水肿和蛛网膜下腔出血后的慢性脑积水的背景下，考虑了 glymphatic 功能。这些例子强调了淋巴系统在神经生理学和某些神经病理学异常的发展中的重要作用，强调了在解释神经影像学研究时考虑它的重要性。

©北美放射学会，2021