IBZM- and CIT-SPECT of the dopaminergic system in parkinsonism.

Parkinsonism is most of the time caused by idiopathic Parkinson's disease (IPD). Considering the differences in therapeutic response and prognosis, in vivo discrimination between IPD and "parkinsonism-plus" syndromes is important. Recently, ligands have become available for imaging the pre- and postsynaptic dopaminergic system by Single Photon Emission Computed Tomography (SPECT). Visualization of postsynaptic D2 dopamine receptors using 123I-iodobenzamide (123I-IBZM) may contribute to the differential diagnosis between IPD and "parkinsonism-plus" syndromes as IPD is a pure presynaptic disease. Imaging of the presynaptic dopamine transporters using [123I] beta-CIT (2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane) may be used as a diagnostic technique. Early disease detection in subjects suspected to be at risk for developing IPD has become possible using [123I] beta-CIT or other ligands for the dopamine transporter. Furthermore, with SPECT one is probably able to monitor in an objective way the efficacy of new pharmacological therapies.