The role of functional neuroimaging in the differential diagnosis of idiopathic Parkinson's disease and multiple system atrophy.

Parkinsonism is a symptom of a number of neurodegenerative disorders in the elderly. Even though clinical criteria for various parkinsonian disorders have been developed recently, the differential diagnosis of parkinsonian disorders based on clinical symptoms remains unsatisfactory, particularly in early disease stages. Early differential diagnosis on the other hand is important as prognosis and treatment options differ substantially. Multiple system atrophy (MSA) is one of the major differential diagnoses of idiopathic Parkinson's disease (PD). Radiotracer-based imaging methods such as positron emission tomography (PET) remain the established method for differential diagnosis of parkinsonian disorders. The following paper provides a review of different PET imaging methods for the differential diagnosis of PD and MSA patients.