Functional PET for mapping metabolic dynamics in Parkinson's disease

Static [¹⁸F]-FDG PET studies have shown characteristic metabolic patterns for Parkinson's disease (PD). However static PET scans offer only a snapshot of synaptic activity, preventing insights into dynamics of glucose consumption on individual level. In this study, we apply a novel dynamic constant infusion PET protocol in combination with MRI for mapping metabolic dynamics in PD. Metabolic time series comparison revealed hypometabolism in bilateral clusters in the substantia nigra in PD patients compared to controls (p_FWE < 0.001). The temporal structure allowed us to depict metabolic networks covering the basal ganglia circuits and typical neural resting-state networks on individual level. A measure of time series variation showed a region-specific increase in time series variation in PD, which related to cognitive PD symptoms. The findings pinpoint the methodological capabilities of the acquisition protocol for evaluating metabolic dynamics and metabolic network activity on subject-level in PD. Our study lays a foundation for the application of molecular imaging with temporal resolution in context of neurodegenerative diseases. Such protocols can capture interregional metabolic changes on patient level, the applicability of which should be evaluated in prodromal stages.