Abstract Quantitative T 2 magnetic resonance (MR) imaging was used to examine gerbil brains 1, 3, 10, and 30 days after 5 min forebrain ischemia. T 2 was increased in the dorsal–lateral striatum 1 and 3 days post-ischemia, and in the hippocampus 3 days post-ischemia. T 2 was normal 10 days post-ischemia, and decreased in the hippocampus and dorsal-lateral striatum 30 days post-ischemia. Neuronal counts in the dorsal-lateral striatum and CA1 hippocampal region were uniformly decreased 30 days post-ischemia. The increase in T 2 shortly after ischemia is attributed to brain edema localized to regions where neuronal injury developed. The late decrease in T 2 may be due to decreased water in gliotic tissue, or to ferritin-positive microglia, following forebrain ischemia. Tissue atrophy at later times gave enlarged ventricles on MR images.