In this study the mechanical properties of the mouse brain were continuously sampled by fast magnetic resonance elastography during ketamine/xylazine induced dying. Mechanical properties were correlated with metabolic and physiological imaging markers. Immediately after respiration arrest, stiffness of the whole brain and the hippocampus increased significantly while cardiac functioning was intact and reached a plateau ca. 5 min after ECG stop. Stiffness increase was inversely correlated with diffusion decrease. Results suggest that during the process of dying cytotoxic edema and brain swelling occurs leading to significant tissue stiffening.