Abstract
PURPOSE OF THE STUDY: This study compared striatal dopamine metabolism and cerebral glucose metabolism in Parkinson's disease patients with and without freezing of gait (FOG) using Fluorodeoxyglucose positron emission tomography (FDG-PET) and F-DOPA PET. We also compared the two groups' cognitive, affective, and autonomic functions. METHODS: Patients were divided into two groups: those with and without FOG. All patients underwent neuropsychological evaluation. Subsequently, both groups underwent FDG-PET and FDOPA-PET. The FDOPA PET/computed tomography images evaluated dopaminergic expression in the basal ganglia. Cortex-ID-based processing of FDG images was visually analyzed for any abnormal hypermetabolism or hypometabolism in the various regions of the brain. RESULTS: A total of 30 patients were recruited, 15 in each group. The mean age of participants was 59.33 ± 9.12 years in the freezing of the gait-negative group and 61.13 ± 9.38 years in the freezing of the gait-positive group. FDOPA PET scan analysis revealed symmetrical loss of basal ganglia uptake in the freezers compared to the nonfreezers, which had more asymmetrically reduced uptake (P = 0.025). In FDG PET, a general trend of greater metabolic reduction in the basal ganglia was observed in freezers. Our study showed bilateral involvement of frontoparietal cortices in both freezers and nonfreezers, with more widespread areas of hypometabolism reported in the freezer group. CONCLUSION: Freezers exhibited a more symmetrical loss of dopaminergic uptake on FDOPA PET, whereas nonfreezers showed greater asymmetry. In addition, FDG PET revealed a trend toward greater basal ganglia hypometabolism in freezers, suggesting a more profound striatal dysfunction in patients with freezing of gait.