Reorganization of brain connectivity in post-COVID condition: a 18F-FDG PET study, 2025, Verger et al.

Reorganization of brain connectivity in post-COVID condition: a 18F-FDG PET study
Verger, Antoine; Doyen, Matthieu; Heyer, Sebastien; Goehringer, François; Bruyere, Alexandra; Kaphan, Elsa; Chine, Meriem; Menard, Amélie; Horowitz, Tatiana; Guedj, Eric

A hypometabolic brain pattern has been reported in patients with post-COVID condition (PCC). The aim of this study was to investigate reorganization in metabolic connectivity in patients with PCC.

One hundred eighty-eight patients who underwent brain 18F-FDG PET for PCC were retrospectively included from two university hospital centres. These patients were age-and sex-matched to 120 healthy controls who underwent brain 18F-FDG PET before the COVID-19 outbreak. A voxel-based group comparison between patients and controls was performed (p-voxel at 0.005 uncorrected, p-cluster at 0.05 FWE corrected). Interregional correlation analyses of the identified clusters as well as sparse inverse covariance estimations at whole-brain scaling were also conducted. Both analyses were performed at the group level for all patients and then secondarily according to the postinfection delay; 88 and 100 patients, respectively, had a delay of less than or greater than 9 months (± 9 M).

Three hypometabolic clusters, namely, the right frontotemporal, right and left cerebellar, were identified from the voxel-based group comparisons of PCC patients. Within this hypometabolic PCC pattern, a modification in metabolic connectivity was observed in patients compared with controls, which was more marked in the + 9 M group than in the − 9 M group. On the other hand, the graph analysis revealed a decrease in connectivity efficiency metrics in the PCC.

Metabolic connectivity is modified in patients with PCC within the hypometabolic post-COVID-19 network, with lasting reorganization evolving over time, suggesting functional adaptation.

Link | PDF (EJNMMI Research) [Open Access]

 

Definition of PCC?

So, there was a high level of selection of the cases - they had been referred for investigation of brain impairment before this study was undertaken.

I think the cases probably had brain impairment for a range of reasons. One reason might possibly be an ME/CFS-like condition. But, another reason could be having had a very severe respiratory illness e.g. hypoxia. Other reasons might be coincidental e.g. onset of dementia, or mechanical brain injury.

 

Here's some examples of causes of cerebellar hypometabolism:

These causes might have prompted the investigation, and not be related to the Covid infection.