MAPT and ischemia: Previous studies have shown that there is a decline in osmolytes, an increase in intracellular water content, and accumulation of sodium in the ischemic brain tissue.25,33, 34, 35, 36 Interestingly, sodium magnetic resonance imaging in rats has been proposed as a way to estimate stroke onset time.36 We hypothesized that the evolution of these metabolites, e.g., NAA and Tau, after permanent occlusion might enable evaluation of the ischemia onset time.