Progression in Parkinson's disease: a positron emission tomography study with a dopamine transporter ligand [18F]CFT.

We studied the rate of progression of striatal dopamine transporter function in Parkinson's disease (PD). Eight patients with early PD without antiparkinsonian medication and 7 healthy volunteers were investigated with [18F]CFT positron emission tomography (PET). The PET scan was carried out twice at an approximate 2-year interval. The uptake of [18F]CFT was calculated as a region-cerebellum:cerebellum ratio at 180 to 210 minutes after injection. At the first PET scan, the [18F]CFT uptake in PD patients in the putamen was 1.45 +/- 0.45 (mean +/- SD) (42% of the control mean) and 2.43 +/- 0.59 in the caudate nucleus (76% of the control mean). The ratios declined by the time of the second PET scan, and the rate of annual decline of the baseline mean in PD patients was 13.1% in the putamen and 12.5% in the caudate nucleus. In controls, the corresponding figures were 2.1% for the putamen and 2.9% for the caudate nucleus. The decline in [18F]CFT uptake was significantly higher in PD patients than in controls. Thus, dopamine transporter ligands such as [18F]CFT seem to be sensitive markers for the rate of progression in PD.