Biomarkers.

Area of Science:

• Neuroradiology
• Neuroimaging
• Cerebrospinal Fluid Dynamics

Background:

• Neurofluids are crucial for clearing brain proteins like amyloid and tau.
• Previous MRI studies with intrathecal gadolinium-based contrast agents (GBCA) showed CSF to brain tissue transport.
• Intravenous (IV) GBCA studies suggest blood-to-CSF transfer but often lack sufficient time points for detailed analysis.

Purpose of the Study:

• To investigate the transport of IV-GBCA from the vascular system into the cerebrospinal fluid (CSF) compartment.
• To track the movement of contrast agents within the brain's fluid spaces over a 24-hour period using hourly MRI scans.
• To understand the mechanisms and rates of contrast transport into different brain compartments.

Main Methods:

• Seven healthy adults underwent 24 hourly MRI scans for 22 hours post-IV GBCA administration (Gadobutrol).
• Imaging techniques included 3D-QALAS for T1/T2 mapping and T2-weighted FLAIR sequences.
• GBCA concentration was calculated using T1 mapping data in various brain regions and CSF spaces.

Main Results:

• GBCA was detected in the cerebrospinal fluid (CSF) within 20 minutes, with higher concentrations initially in the subarachnoid space (SAS) than the lateral ventricles (LV).
• Sustained GBCA was observed in the parasagittal dura, and contrast retention varied significantly, with the optic nerve showing the longest retention (∼19 hours).
• No parenchymal enhancement was observed, indicating contrast remained within the CSF spaces and associated structures.

Conclusions:

• Intravenous GBCA is effective for tracking contrast transport from the vasculature into the CSF compartment.
• GBCA transfers to the ventricles and SAS via multiple pathways, demonstrating differential transport rates across various cranial nerves.
• The study highlights the dynamic nature of CSF transport and provides insights into GBCA distribution patterns.