PET Molecular Imaging in Atypical Parkinsonism.

Multiple System Atrophy, Progressive Supranuclear Palsy, and Corticobasal Degeneration are three neurodegenerative disorders characterized by parkinsonism along with involvement of other brain cortical and subcortical regions. The ante mortem diagnosis of these disorders is extremely challenging with up to a quarter of these patients being misdiagnosed, particularly in the early stages of disease. While highly specific and sensitive imaging biomarkers of individual atypical parkinsonisms have not been identified yet, molecular PET and SPECT imaging have improved our knowledge of the physiopathology and neuropathology of these disorders and are often used as supportive criteria for the differential diagnosis of these conditions. This chapter will provide a state-of-the-art overview of the use of PET in atypical parkinsonisms.