Changes in cerebral glucose metabolism among mild long COVID patients: an [18F]FDG PET/CT study

COVID-19, caused by SARS-CoV-2, presents diverse symptoms, including neurological manifestations. This study investigated COVID-19's neurological sequelae, focusing on the central nervous system's involvement through cerebral glycolytic metabolism assessed via PET/CT. Twenty-two patients with mild long COVID cognitive symptoms and 20 healthy volunteers without cognitive, psychiatric, or neurological impairments and no history of COVID-19 infection underwent cerebral PET/CT scans using [18F]FDG to assess cerebral metabolism. The study meticulously evaluated the uptake of [18F]FDG in various brain regions, employing the CortexID Suite software for quantitative analysis. The analysis focused on identifying areas of hypometabolism and hypermetabolism, indicative of altered glucose metabolism possibly related to COVID-19's neurological impact. No statistically significant differences were found between the mild COVID and healthy groups. Although our sample was too small to generate a statistical difference between groups, future studies should explore some findings, such as hypometabolism in 15 regions and hypermetabolism in 11 regions in the mild COVID group. These changes, especially in areas linked to executive functions, sensory perception, and emotional regulation, suggest nuanced alterations in brain function. Our study did not find significant glycolytic metabolic changes in patients with mild long COVID. However, areas of glycolytic hypometabolism and hypermetabolism found in some patients showed biological plausibility with the cognitive and affective symptoms they presented. Future investigations with a larger sample size should be correlated with neuropsychological and neuropsychiatric examinations to confirm this relationship.