CT abnormalities evocative of lung infection are associated with lower ¹⁸F-FDG uptake in confirmed COVID-19 patients.

Abstract

CT signs that are evocative of lung COVID-19 infections have been extensively described, whereas ¹⁸F-FDG-PET signs have not. Our current study aimed to identify specific COVID-19 ¹⁸F-FDG-PET signs in patients that were (i) suspected to have a lung infection based on ¹⁸F-FDG-PET/CT recorded during the COVID-19 outbreak and (ii) whose COVID-19 diagnosis was definitely established or excluded by appropriate viral testing. Twenty-two consecutive patients referred for routine ¹⁸F-FDG-PET/CT examinations during the COVID-19 outbreak (March 25th to May 15th 2020) and for whom CT slices were evocative of a lung infection were included in the study. All patients had undergone a SARS-COV-2 diagnostic test to confirm COVID-19 infection (positivity was based on molecular and/or serological tests) or exclude it (negativity of at least the serological test). Eleven patients were confirmed to be affected by COVID-19 (COVID+), whereas the other eleven patients were not (COVID-) and were predominantly suspected of having bacterial pneumonia. CT abnormalities were not significantly different between COVID+ and COVID- groups, although trends toward larger CT abnormalities (p = 0.16) and lower rates of consolidation patterns (0.09) were observed in the COVID+ group. The maximal standardized uptake values (SUV_max) of lung areas with CT abnormalities were however significantly lower in the COVID+ than the COVID- group (3.7 ± 1.9 vs. 6.9 ± 4.1, p = 0.03), with the highest SUV_max consistently not associated with COVID-19. Among CT abnormalities evocative of lung infection, those related to COVID-19 are associated with a more limited ¹⁸F-FDG uptake. This observation may help improve our ability to detect COVID-19 patients.