Brain FDG PET imaging of patients with persistent post- COVID-19 fatigue

ABSTRACT

Aim/Introduction: A recent report prepared by the Centers for Disease Control and Prevention indicates that 71% of patients experience persistent fatigue even after recovery from the acute phase of COVID-19 infection. We investigated if post-COVID-19 fatigue is associated with alterations in brain metabolism and microstructure to better understand the underlying neurobiological mechanism. Material(s) and Method(s) Brain F-18 FDG PET and diffusion tensor magnetic resonance imaging (DTIMR) were performed in 12 patients experiencing persistent post- COVID-19 fatigue that lasted more than six weeks post-discharge from hospitalization or discontinued home isolation after acute SARS-CoV-2 infection (fatigue group, MaleFemale = 66, mean > SD age 35.7 > 13.8 years, Chalder fatigue scale score 8.3 > 2.2, time since COVID-19 diagnosis 7.9 > 5.5 months) and 9 recovered patients without such fatigue (non-fatigue group, MF = 36, age 25.6 > 9.2, fatigue score 1.6 > 1.5, time since COVID-19 diagnosis 8.0 > 6.0 months). A commercially available normative brain FDG PET database (MIMneuro, v7.0.5, MIM Software, Inc.) was used to derive z scores for regional cerebral glucose metabolism. Fractional anisotropy (FA) values were extracted from DTI-MR datasets. Twotailed t-tests were performed for group comparison and P < 0.05 was considered statistically significant. Result(s) The fatigue group demonstrated significantly higher regional cerebral glucose metabolism in the left inferior and middle cerebellar peduncle (P = 0.001 and 0.043, respectively), left middle temporal gyrus (P = 0.002), left parahippocampal gyrus (P = 0.029), primary visual cortex (P = 0.031), supplementary motor area (P = 0.036), supramarginal gyrus (P = 0.044), and lower metabolism in the left precentral gyrus (P = 0.001) when compared to the non-fatigue group. The fatigue group also demonstrated significantly higher FA values in the left and right middle frontal gyrus (P = 0.014 and 0.038, respectively), left precentral gyrus (P = 0.024), right superior frontal gyrus (P =0.032), right postcentral gyrus (P = 0.047), left superior parietal gyrus (P = 0.048), and corpus callosum (P = 0.016) when compared to the nonfatigue group. Conclusion(s) Patients experiencing persistent fatigue after recovering from acute SARS-CoV-2 infection demonstrated significant changes in regional cerebral glucose metabolism and microstructure, when compared to those individuals without on-going fatigue symptoms. The altered cerebral metabolic and microstructural profile may help to better understand the neurobiological mechanism for management of patients suffering from lingering post-COVID-19 fatigue.