Use of a single [123I]-FP-CIT SPECT to predict the severity of clinical symptoms of Parkinson disease.

The aim of this study was to assess the ability of a single SPECT performed in the early stage of Parkinson's disease (PD) to predict disease severity in 19 patients with early PD. [(123)I]-FP-CIT striatal uptake was expressed as a ratio of specific:nonspecific uptake for defined brain areas. Clinical severity was determined by the UPDRS at baseline and 12-15 months following the SPECT procedure. [(123)I]-FP-CIT uptake in the contralateral putamen and striatum was correlated with UPDRS score at baseline, with a more significant correlation after 1-year interval. [(123)I]-FP-CIT uptake in all areas was correlated with bradykinesia and rigidity subscores only at follow up visit. Significant correlations were found between [(123)I]-FP-CIT uptake in the contralateral striatum, putamen and caudate and the difference between motor scores of 1-year interval (DeltaUPDRS). These results suggest that disease severity might be anticipated by a single SPECT at an early stage of the disease.