Visualization of Glymphatic Route on the Rat Cerebral Surface Using Direct Injection of 17O-Labeled Water and Proton MRI

Motivation: Understanding water dynamics on the cerebral surface is crucial for advancing neurofluid research and exploring the glymphatic hypothesis and the subarachnoid lymphatic-like membrane (SLYM). Goal(s): Detailed visualization of water dynamics on the surface of the brain using a water tracer. Approach: 17O-labeled water was directly injected into the subarachnoid space (SAS) of the rat cerebrum to increase local concentration for detailed observation of water dynamics. Results: The inner SAS group showed a higher concentration of 17O-labeled water, with vertical distribution patterns observed on the cortical surface, suggesting potential pathways for CSF flow into brain parenchyma. Impact: Using the technique of local subarachnoid injection of 17O-labeled water and an optimiszd proton MRI method, we were the first to visualize CSF inflow pathways in the cerebral cortex as distinct signal changes.