DAT imaging in drug-induced and psychogenic parkinsonism.

Parkinson's syndrome (PS) is frequently encountered in disorders associated with prominent degeneration of the nigrostriatal pathway as in Parkinson's disease, multisystem atrophy, and progressive supranuclear palsy (presynaptic PS). Drug-induced parkinsonism, a common, underdiagnosed health problem and psychogenic parkinsonism are causes of Parkinson's syndrome which, evidence suggests, occurs without degeneration of nigrostriatal structures. We review clinical features and results of DAT imaging in drug-induced parkinsonism and psychogenic parkinsonism. These two conditions normally give normal striatal DAT imaging results; an abnormal result in either case could exclude both conditions, corroborating a diagnosis of organic parkinsonism in uncertain cases.