Neuroimaging methods applied in Parkinson's disease.

Radiotracer methods provide regional in vivo quantified information about specific biochemical activities in brain tissue. The understanding of the principles governing radiotracer uptake into brain tissue determines the potential value of these tracers in assessing pathophysiology of brain diseases. Too often a reductionist view of images is taken to directly point to clinical features or even diagnoses of brain diseases. Parkinson's disease like many other neurodegenerative brain diseases is a multisystem disorder of considerable biological and clinical complexity while the information given by regional cerebral tracer uptake points to a momentary biochemical local tissue feature. Examples applying to the well-known dopaminergic tracers are given.