The sensitivity of 18-fluorodopa positron emission tomography and magnetic resonance imaging in Parkinson's disease.

Parkinson's disease (PD) as the most important movement disorder is characterized by a progressive loss of nigral dopamine neurons and a subsequent degeneration within several other transmitter systems. Functional brain imaging with positron emission tomography (PET) and the radiotracer 18-fluorodopa (FDOPA) is capable to quantify the deficiency of dopamine synthesis and storage within pre-synaptic striatal nerve terminals. Therefore, FDOPA-PET allows the diagnosis of PD in early disease stages and the differentiation of clinically unclear cases from other movement disorders, e.g. essential tremor. Additionally, FDOPA-PET imaging permits the follow-up of disease progression, the assessment of medical and surgical PD therapy strategies with possible neuroprotective properties and the detection of pre-clinical disease in subjects at risk for the disorder. The classical domain of morphological magnetic resonance imaging (MRI) is the differentiation of symptomatic Parkinsonism from PD. However, recent advances in MRI data acquisition and analysis techniques demonstrated MRI to be also a valuable tool for detection of nigral pathology in PD and for differentiation of neurodegenerative disorders with atypical Parkinsonism.