English: (a) Axial diffusion‑weighted magnetic resonance imaging and apparent diffusion coefficient map, demonstrating increase in cortical signal on

the diffusion‑weighted sequence and corresponding decrease in apparent diffusion coefficient. This is cortical diffusion restriction. (b) Images from the 18fluoro‑deoxy‑glucose component of the positron emission tomography/computed tomography: An axial section at the level of the basal ganglia and a coronal section including the cerebellum. Both show heterogeneous marked reduction in cerebral cortical metabolism. 18Fluoro‑deoxy‑glucose uptake in cerebellar cortex is preserved (normally less avid than cerebral cortex). There is some more subtle hypometabolism affecting the left basal ganglia and thalamus. (c) Photomicrographs of sections of occipital cortex, the upper is stained with hematoxylin and eosin, and the lower with KG9 antibody following

proteinase treatment. 20 μm scale bar. They show spongiform change in the striate cortex and proteinase resistant prion deposits