Purpose: To determine clinical predictors and accuracy of (123)I-FP-CIT SPECT imaging in the differentiation of drug-induced parkinsonism (DIP) and Parkinson's disease (PD).
Methods: Several clinical features and (123)I-FP-CIT SPECT images in 32 patients with DIP, 25 patients with PD unmasked by antidopaminergic drugs (PDu) and 22 patients with PD without a previous history of antidopaminergic treatment (PDc) were retrospectively evaluated.
Results: DIP and PD shared all clinical features except symmetry of parkinsonian signs which was more frequently observed in patients with DIP (46.9%) than in patients with PDu (16.0%, p<0.05) or PDc (4.5%, p<0.01). Qualitatively (123)I-FP-CIT SPECT images were normal in 29 patients with DIP (90.6%) and abnormal in all patients with PD, and this imaging technique showed high levels of accuracy.
Conclusion: DIP and PD are difficult to differentiate based on clinical signs. The precision of clinical diagnosis could be reliably enhanced by (123)I-FP-CIT SPECT imaging.