The Regulation of Cerebral Spinal Fluid Flow and Its Relevance to the Glymphatic System.

PURPOSE OF REVIEW: The glymphatic system is a relatively new concept that has been associated with regulation of cerebrospinal fluid (CSF), as well as brain waste clearance. Novel techniques to study glymphatic dysfunction have in turn prompted a reassessment of brain physiology and underlying elements of neurological disease. This review incorporates a contemporary imaging perspective focused on understanding the regulation of CSF flow, thus expanding the putative clinical relevance of this system and the relationships between CSF flow and glymphatic function. RECENT
FINDINGS: MR imaging studies, especially those that employ intrathecal gadolinium contrast, have identified potentially new pathways regulating CSF production, absorption, and clearance. These studies, when viewed in the context of more historical anatomic descriptors of CSF production and absorption, provide a more robust description of CSF physiology and waste clearance. CSF production and resorption are under-investigated and could be related to various pathophysiologic processes in neurodegeneration. Anatomically based clinical exemplars of CSF clearance are discussed. Future studies should focus on linking glymphatic functionality with neurological disease.