Correlation of Parkinson's disease severity and F-FDG and F-FP-DTBZ PET.

Background: Positron emission tomography (PET) using the tracer F-fluorodeoxyglucose (F-FDG) and [F] 9-fluoropropyl-(+)-dihydrotetrabenazine (F-FP-DTBZ) is widely utilized to measure metabolic activity and dopaminergic integrity in neurodegenerative diseases such as Parkinson's disease (PD). Previous studies employing F-FDG PET have primarily focused on motor or non-motor symptoms, rather than the severity of PD. This study aimed to measure the glucose metabolism of F-FDG and the dopaminergic function of F-FP-DTBZ across various Hoehn-Yahr (H&Y) stages, analyzing the correlation between metabolic activity, dopaminergic function, and H&Y stages to monitor the severity of PD.

Methods: The cross-sectional study recruited 78 PD patients in 3 groups of H&Y stages I, II, and III-V and 18 healthy control (HC) participants to undergo F-FDG and F-FP-DTBZ PET scans. Differences in cerebral metabolism and dopaminergic function between groups were evaluated using Student's -test and Mann-Whitney test. Moreover, Pearson correlation analysis was used to explore the association between cerebral metabolism, dopaminergic function, and H&Y stages in all patients.

Results: Patients with PD exhibited significant hypometabolic activity in the frontal cortex and relative hypermetabolic activity in the putamen, globus pallidus, thalamus, and cerebellum when compared to HC individuals (P<0.05). Further imaging-clinical correlation research depicted the negative correlation between the metabolic activity in the frontal and putamen regions with H&Y stage. Furthermore, the F-FP-DTBZ binding reductions were 18.6%, 46.6%, and 56.9% for the caudate, anterior putamen, and posterior putamen at H&Y stages I; 36.0%, 56.9%, and 65.9% at H&Y stages II; and 41.2%, 61.9%, and 68.5% at H&Y stages III-V, respectively. The F-FP-DTBZ binding of caudate, anterior putamen, and posterior putamen exhibited significantly negative correlations to H&Y stage.

Conclusions: In PD, F-FDG and F-FP-DTBZ PET imaging represent potential biomarkers for tracking metabolic activity and dopaminergic degeneration, offering valuable insights into estimating the severity of disease.