Similar patterns of [F-18]-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 [F-18]-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 [F-18]-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 [F-18]-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.