Positron emission tomography in parkinsonism.

Positron emission tomography provides researchers and clinicians with information on cerebral blood flow, metabolic pathways or neurotransmission systems, which may help to understand the physiopathology of movement disorders. Studies of the nigrostriatal dopaminergic pathway and data on cerebral glucose metabolism contribute to discriminate between parkinsonian syndromes. New techniques for image processing and statistical analysis, and brain activation studies better emphasize dysfunction of cortico-subcortical neuronal networks responsible for movement disorders, or functional modification after therapeutic action.