ABSTRACT
Aim/Introduction: In SARS-CoV2 outbreak scenario, many considerations about possible long-term effects of this infection can be made. Early evidences reported in literature about the relation between long-COVID disease and brain involvement in patients with persistent neurological symptoms, found brain hypometabolism on 18F-FDG PET/CT. Our study aims to evaluate the impact of SARSCoV2 infection on brain metabolism in a long-term setting, also in asymptomatic patients. Material(s) and Method(s): Brain PET scans of 48 patients with documented previous SARS-CoV2 infection (COVID-group), performed from January to December 2021, were analysed and compared with brain PET scans of 48 patients, controlled for age and sex, who didn't experience the infection (control-group) using a quantitative software-aided approach. Patients with documented brain metastases or neurodegenerative diseases were excluded. No patient had neurological symptoms at the time of PET. CortexID Suite software (GE Healthcare) was applied for a segmentation analysis reporting Z score (ZS) values for each brain area in both groups. Basing on hypometabolism severity, the sample was divided as follows: normal (>=-1 ZS), mild (between -1 and -2 ZS), severe (<=-2 ZS). For COVID-group, time intercurred from infection to PET was recorded. Differences between ZS per areas between the two groups were evaluated using Mann-Withney-U test. Considering hypometabolism severity, Chi-Square test was applied to evaluate differences between groups. Finally, Pearson's test was used to correlate COVID-group ZS and time intercurred from infection. Result(s): Mean age of patients was 63.2 and 63.6 years old in the COVID-and control-group respectively. In both groups, 22/48 were male. In COVID-group 27/48 patients have had symptoms (cough, fever, dyspnoea) during SARS-CoV2 infection. The majority of brain areas showed a statistically significant difference in ZS values between groups. According to hypometabolism severity, left pre-frontal medial (p=0.032), right sensory-motor (p=0.014), right inferior parietal (p=0.001) and right lateral temporal (p=0.002) areas showed a statistically significant difference between COVIDand control-group with a prevalence in COVID-group of mild and severe brain hypometabolism. Lower ZS values were observed in patients with a longer time intercurred from infection to PET/CT scan. Conclusion(s): Our preliminary results confirm the impact of SARS-CoV2 infection on brain metabolism, consisting mostly in a mild hypometabolism. The presence of this metabolic pattern in patients without neurological symptoms suggests a devious action of the infection. Further studies, also using serial PET, are necessary to explore whether these metabolic alterations are transient or predictive of a future clinical manifestation.