Comparison of 18F-DOPA and 18F-DTBZ for PET/CT Imaging of Idiopathic Parkinson’s Disease

Abstract Objective: To compare the two imaging tracers 18F-DOPA and 18F-DTBZ for PET/CT imaging in idiopathic Parkinson’s Disease (PD). Methods: 32 patients with final diagnosis of idiopathic PD and 12 healthy controls were recruited in our study. The clinical symptoms of PD patients were evaluated by using the UPDRS-III and modified H-Y stage. All subjects underwent both 18F-DOPA and 18F-DTBZ PET/CT, and the results were interpreted by visual analysis and semi-quantitative analysis. Semi-quantitative analysis was performed to calculate the specific uptake ratios (SURs) in the subregions of striatum with the occipital cortex as reference area. A one-way ANOVA test was used to compare the clinical data and the SURs among the patients at different stages. Regression analysis was performed to analyze the correlation between the SURs and the clinical data. A kappa test was used to evaluate the consistency of the visual inspection results. Results: Among the PD patients, there were 7 patients in H-Y stage I, 14 patients in stage II, and 11 patients in stage III. No statistical difference in age or gender was found among the three groups (p >0.05). The semi-quantitative analysis of 18F-DOPA and 18F-DTBZ PET images showed that PD patients in different stages had significantly lower SURs in the striatum than the healthy controls (p <0.05), and the SURs generally decreased with the progression of PD staging (p<0.05). An exponential correlation was found between the SURs of each tracer in the putamen with the UPDR-III score (p <0.05), and a linear correlation was found in striatum SURs between two tracers (p<0.05). By visual analysis, 18F-DOPA detected 29 cases with bilateral uptake decrease and the other 3 stage I cases with unilateral uptake decrease, while 18F-DTBZ detected 26 cases with bilateral uptake decrease and 6 cases with unilateral uptake decrease. The overall consistency of visual analysis between these two tracers was 90.63% (Kappa=0.62, p < 0.001).Conclusion: Both 18F-DTBZ and 18F-DOPA are reliable imaging tracers for PET/CT imaging in PD patients with good consistency, and they have the same level of striatal SURs decline percent for PD patients in early stages.