We have developed the first non-invasive technique that is able to detect changes in brain AQP4-mediated clearance pathways. Our multi-TE ASL technique measures the exchange of vascular water into cortical brain tissue of mouse brain. We report a significant increase in the cortical exchange time between WT (377 ± 89ms) and AQP4-deficient (536 ± 92ms) mice. While measured CBF, ADC and δa did not detect differences, suggesting preserved haemodynamic and energetics between groups. This highlights the novelty of the technique being targeted method to assess water transport in brain clearance pathways, to help better understand neurodegenerative diseases.