Quantifying Ventricular CSF Clearance in the Human Brain Using Dynamic 18F-FDG PET: Insights into Age-Related...

Area of Science:

• Neuroscience
• Medical Imaging
• Biochemistry

Background:

• The glymphatic system clears brain waste via cerebrospinal fluid (CSF) flow.
• Glymphatic system dysfunction is linked to aging and neurodegeneration.
• Current methods to quantify human glymphatic function are limited.

Purpose of the Study:

• To assess dynamic 18F-FDG PET for measuring ventricular CSF clearance as a surrogate for glymphatic function.
• To evaluate the association of CSF clearance with age.
• To determine test-retest reliability and feasibility of reduced scan durations for clinical application.

Main Methods:

• Analysis of 72 baseline 18F-FDG PET scans.
• Estimation of CSF influx and clearance parameters using time-activity curves and a gamma-variate model.
• Correlation and regression analyses for age and clinical factors; test-retest reliability assessed in 11 participants.

Main Results:

• CSF clearance showed a significant negative correlation with age (r = -0.680, p < 0.001).
• Age was a significant predictor of CSF clearance, independent of covariates.
• Test-retest analysis yielded moderate-to-good reproducibility (ICC = 0.702); shortened scans (30 min) retained key correlations.

Conclusions:

• Dynamic 18F-FDG PET offers a reliable, noninvasive method for quantifying ventricular CSF clearance.
• The study demonstrates age-related decline in glymphatic function and the method's reproducibility.
• Findings support 18F-FDG PET as a clinically feasible tool for studying brain clearance in aging and disease.