Systems and methods for providing quantitative measurements of global glymphatic flow of cerebrospinal fluid (“CSF”) using magnetic resonance imaging (“MRI”) are described. In general, images are obtained from a subject using flow-sensitive MRI techniques that are designed to be particularly sensitive to the glymphatic flow of CSF. Measures of glymphatic flow can be obtained while the subject is in an awake state and again while the subject is in a sleep state. Based on these two measurements, a biomarker that indicates a neurological state or disease can be generated.
