[Recent concepts on cerebral ischemia in humans and their implications in therapeutic evaluations]

Recent concepts concerning focal cerebral ischaemia in man and resulting from the data obtained with positron emission tomography are reported. The evolutive steps in the ischaemic process are divided into: perfusion reserve; extraction reserve recruitment; ischaemic penumbra; lesional process, and post-lesional developments. Circulatory and metabolic patterns corresponding to these evolutive steps are described and illustrated. The potentials of these data as guide-lines in therapeutic trial methodology are discussed.