We report a 72-year-old man with Creutzfeldt-Jakob disease. He showed a progressive dementia, myoclonus, and other neurological symptoms. DNA analysis showed a normal variation of prion gene (codon 129, Met/Met: codon 219, Glu/Glu). He had periodic synchronous discharge on electroencephalogram and brain atrophy on CT scan and MRI. Diffusion images on his brain MRI revealed a marked increase in signal intensity in the caudate nuclei, putamen, and cerebral cortices. These changes may represent spongy changes of the brain and seem to be a feature of brain MRI in Creutzfeldt-Jakob disease.