Brain tissue water comes in two pools: Evidence from diffusion and R2' measurements with USPIOs in non human primates

► Brain ADC values and USPIO relaxivity effects seem coupled using standard BMS model. ► USPIO and diffusion effects could be uncoupled using a model with 2 water pools. ► The fast and a slow diffusion pools also have different relaxivities. ► Diffusion-weighting emphasizes the slow pool contribution (decrease in ADC and R2'). ► Those results have implications for BMS contrast agents as well as fMRI studies.