[18F]-FDG PET/CT in oncologic patients with unsuspected asymptomatic infection with SARS-CoV-2

Abstract

Purpose Spain has been one of the most affected countries by the COVID-19 pandemic, being among the countries with worse numbers, including the death rate. However, most patients are asymptomatic, although they are very contagious. The objective of this study was to investigate the incidence in oncological patients infected with SARS-CoV-2 that are asymptomatic for COVID-19 and at home and that undergo PET/CT for oncologic indications, nonrelated to COVID-19, finding in the PET/CT lung alterations that are suggestive of SARS-CoV-2 infection. Methods During the period of maximum incidence of the global pandemic in one of the most affected regions of Spain, there were 145 patients that met inclusion and exclusion criteria and were included in the study. Imaging findings previously described such as ground-glass opacities with low [ 18 F]-FDG uptake were considered images suspicious for SARS-CoV-2 infection. Patients with these findings were referred to RT-PCR testing and close follow-up to confirm the presence or absence of COVID-19. Results Suspicious lung imaging findings were present in 7 of 145 patients (4.8%). Five of these 7 patients were confirmed as presenting SARS-CoV-2 infection, this is, COVID-19. In the remaining two, it was not possible to confirm the presence of COVID-19 with RT-PCR, although in one of them, PET/CT allowed an early diagnosis of a lung infection related to a bacterial pneumonic infection that was promptly and adequately treated with antibiotics. Conclusion These results confirm that the prevalence of SARS-CoV-2 infection is higher than suspected and that there are asymptomatic patients that are attending imaging departments to be explored for their baseline oncologic processes. In these patients, PET/CT allows an early diagnosis of COVID-19.

Role of 2-[18F]FDG as a Radiopharmaceutical for PET/CT in Patients with COVID-19: A Systematic Review

“…From the comprehensive computer literature search of PubMed/MEDLINE and Cochrane databases, 169 records were screened. In total, 11 studies were selected and retrieved in full-text version according to the predefined inclusion criteria [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Conversely, 158 records were excluded because case reports or small case series ( n = 51), reviews, editorials, letters ( n = 39) or because they were outside the field of interest of this review ( n = 68).…”

“…In most of the studies, 2-[ 18 F]FDG PET/CT was performed in patients evaluated for standard indications (mostly oncological indications) and incidental findings suspicious of SARS-CoV-2 infection or COVID-19 at whole-body 2-[ 18 F]FDG PET/CT were described [ 7 , 8 , 9 , 10 , 12 , 13 , 14 , 15 , 16 , 17 ]. Only in one study 2-[ 18 F]FDG PET/CT was performed in COVID-19 patients to assess the inflammatory status at the presumed peak of the inflammatory phase [ 11 ].…”

“…Most of the included studies reported the rate of incidental findings suspicious of SARS-CoV-2 infection or COVID-19 at 2-[ 18 F]FDG PET/CT performed for standard indications. This rate largely varied among the included studies from 2.1% to 16.2% of all whole body 2-[ 18 F]FDG PET/CT scans [ 7 , 8 , 9 , 12 , 13 , 14 , 15 , 16 , 17 ], based on the prevalence of SARS-CoV-2 infection or COVID-19 during the examination period in a specific country or region [ 11 , 12 , 16 ]. A significant association of the appearance of imaging findings suspicious for COVID-19 on 2-[ 18 F]FDG PET/CT with gender, sex, age, or ethnicity was not demonstrated [ 12 ].…”

“…A significant association of the appearance of imaging findings suspicious for COVID-19 on 2-[ 18 F]FDG PET/CT with gender, sex, age, or ethnicity was not demonstrated [ 12 ]. Only a percentage of suspicious COVID-19 at 2-[ 18 F]FDG PET/CT was finally confirmed by further examinations (e.g., RT-PCR or serological testing) [ 7 , 8 , 9 , 10 , 12 , 13 , 14 , 15 , 16 , 17 ].…”

“…As reported by all the included studies, the 2-[ 18 F]FDG PET/CT findings suspicious for SARS-CoV-2 infection or COVID-19 are mainly CT signs of interstitial pneumonia (e.g., ground-glass opacities, crazy paving patterns, and/or consolidations) with involvement of both lungs in most of the cases [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ].…”