We studied a 69-year-old man with multiple brain infarcts who died 8 days after being studied with positron emission tomography and (F-18)-fluorodeoxyglucose. Metabolic abnormalities were greater than structural changes in size and extent. They were found in areas with no gross pathologic abnormalities. Remote metabolic effects were attributed both to degeneration of fiber tracts with disconnection of remote structures, as demonstrated by hypometabolism in the left frontal cortex associated with an infarct in the genu of the left internal capsule, and to microscopic infarcts not apparent on gross examination but manifested as hypometabolic regions.