Hierarchical clustering analysis reveals size-dependent transport pathways of cerebrospinal fluid tracer in mouse brain

This study investigated the impact of molecular size on transport kinetics and distribution of intracisternal tracers in mouse brain. Three MRI contrast agents with different molecular sizes were administered via cisterna magna. Their transport in the whole brain was observed by dynamic contrast-enhanced MRI for 2 hours. Our results show that the transport of 17O-water (H217O) was significantly faster and more extensive than the two gadolinium-based tracers (Gd-DTPA and GadoSpin). Time-lagged correlation analysis and clustering analysis also showed different cluster patterns between Gd-DTPA and H217O. These observations suggest the size-dependent differences in forces that drive tracer transport in the brain.