Background and purpose: To investigate the clinical applicability and validity of [123I] iodobenzofuran (IBF) single-photon emission computed tomography (SPECT), the authors analyzed the changes in striatal dopamine D2 receptor binding among 7 patients with Parkinson's disease (PD), 6 patients with progressive supranuclear palsy (PSP) (Hoehn and Yahr stage II to IV), and 8 normal controls.
Methods: SPECT data were acquired every 1 minute for 60 minutes postinjection of 167 MBq [123I] IBF. The binding potential (BP) of the striatum was evaluated by 2 methods: region-of-interest (ROI) analysis by the nonlinear least squares method using blood sampling and time-series brain radioactivities in normal controls and a voxel-by-voxel method based on a region model that provided parametric images of BP without blood sampling.
Results: Statistical parametric mapping indicated that BP in the striatum of PSP patients was significantly lower than that of PD patients and normal controls (P < .005, uncorrected), and there was no significant difference between PD patients and normal controls, even in patients with PD at an advanced stage. Data derived from the ROI method and a simplified reference region model showed good correlations in normal controls, indicating the validity of the latter model.
Conclusions: The results predict that [123I] IBF SPECT, especially voxel-by-voxel BP parametric imaging, can discriminate among extrapyramidal diseases such as PD and PSP and may be applicable for clinical use.