Dopamine Transporter Imaging in Parkinson Disease: Progressive Changes and Therapeutic Modification after Anti-parkinsonian Medications

Parkinson disease (PD) is a slowly progressive neurodegenerative disease characterized by the loss of dopaminergic neurons and terminals in the nigrostriatal system. Dopamine transporter (DAT) imaging is widely performed for the differential diagnosis of PD and other degenerative parkinsonism from essential tremor, vascular parkinsonism, and drug-induced parkinsonism. DAT is the plasma membrane carrier specific to dopamine neurons that are responsible for re-uptaking dopamine from the synaptic cleft back into the nerve ending. DAT binding might reflect striatal presynaptic dysfunction or DAT expression in PD patients. Longitudinal studies of DAT imaging have reported progressive changes from early PD patients. This imaging may be used as a progressive biomarker. Follow-up DAT imaging for therapeutic interventions has been applied for several anti-parkinsonian drugs. We herein review the progressive changes and therapeutic modification of DAT binding by anti-PD medications in early PD patients.