Day–Night Variation and Age-Related Differences in Gadolinium-Based Contrast Media Enhancement i

In this retrospective study, early-phase gadolinium-based contrast agent (GBCA) uptake was evaluated using pre- and post-contrast T1 mapping in 447 brain MRIs performed for suspected movement disorders. Scans were labeled as daytime (n=307) or nighttime (n=140) based on acquisition time, with a median post-contrast T1 mapping window of about 5.9 minutes after GBCA administration.

Regional ΔT1 values were derived for the cerebral and cerebellar cortex, white matter, basal ganglia perivascular spaces, and choroid plexus. Key findings indicate that daytime scans exhibited greater cortical enhancement than nighttime scans, most notably in the frontal, parietal, and temporal cortices.

Enhancement did not differ between day and night in white matter, perivascular spaces, or choroid plexus. Age showed an independent positive association with cortical ΔT1, indicating stronger cortical GBCA retention with increasing age across both day and night groups.

There was no significant interaction between age and time of day. The authors conclude that cortical GBCA retention is modulated by circadian timing and aging, supporting early-phase T1 mapping as a feasible method to assess human glymphatic function.