Similar patterns of [(18)F]-FDG brain PET hypometabolism in paediatric and adult patients with long COVID: a paediatric case series

PURPOSE: Several weeks after COVID-19 infection, some children report the persistence or recurrence of functional complaints. This clinical presentation has been referred as “long COVID” in the adult population, and an [(18)F]-FDG brain PET hypometabolic pattern has recently been suggested as a biomarker. Herein, we present a retrospective analysis of 7 paediatric patients with suspected long COVID who were explored by [(18)F]-FDG brain PET exam. Metabolic brain findings were confronted to those obtained in adult patients with long COVID, in comparison to their respective age-matched control groups. METHODS: Review of clinical examination and whole-brain voxel-based analysis of [(18)F]-FDG PET metabolism of the 7 children in comparison to 21 paediatric controls, 35 adult patients with long COVID and 44 healthy adult subjects. RESULTS: Despite lower initial severity at the acute stage of the infection, paediatric patients demonstrated on average 5 months later a similar brain hypometabolic pattern as that found in adult long COVID patients, involving bilateral medial temporal lobes, brainstem and cerebellum (p-voxel < 0.001, p-cluster < 0.05 FWE-corrected), and also the right olfactory gyrus after small volume correction (p-voxel = 0.010 FWE-corrected), with partial PET recovery in two children at follow-up. CONCLUSION: These results provide arguments in favour of possible long COVID in children, with a similar functional brain involvement to those found in adults, regardless of age and initial severity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00259-021-05528-4.