The Choroid Plexus Water Density in Humans Assessed from High-Spatial Resolution Proton Density MRI: Normative Values and Effect of Time of Day

Motivation: Choroid plexus (ChP) function reflects important processes of the neurofluid circuit, but quantification of perfusion and other parameters requires quantitative knowledge of water density. Goal(s): To quantify ChP water density at high spatial resolution over the course of a day. Approach: 70 proton density MRIs were performed from 15 healthy controls at 7:00-9:00, 11:00-13:00, 16:00-18:00, and 19:00-21:00, and ChP water density was calculated. Results: Across all measures, the ChP water density was calculated to be 0.918 ± 0.080 mL water / mL ChP. There was no significant change in ChP water density throughout the day (p=0.95). Impact: Determining choroid plexus (ChP) water density will provide a method for accurate calculation of ChP perfusion, leading to an improved physiological understanding of the role of the ChP as the most proximal component of the neurofluid circuit.