Prof. Antonio Maldonado

Head of Nuclear Medicine and Molecular Imaging Department

Quironsalud Madrid University Hospital, Spain

INTRODUCTION:

The aim of this study was to retrospectively analyse the incidence of suspicious imaging findings of COVID-19 in PET/CT performed in asymptomatic patients referred to our Department with oncologic indications.

MATERIALS AND METHODS:

We analyzed retrospectively the PET-CT scans performed in a tertiary center between March–November 2020. A number of 1300 patients were evaluated for types of cancer during their oncologic protocol. Inclusion criteria: confirmed cancer, indication for PET-CT in initial staging, follow-up or monitoring of the treatment response. Exclusion criteria: none of these patients were symptomatic for an acute respiratory disease and all of them passed through an epidemiologic screening including: clinical data, information about a possible contact with an infected person, travel in known COVID–19 areas.

RESULTS:

Suspicious metabolic COVID-19 lung findings were present in 70 of 1300 patients (5.4%). The most frequent primary was lung cancer (44%), lymphoma (19%), breast cancer (16%) and other tumors in 21% of cases. We observed preferently these findings in FDG scans (Figure 1) but also in 68Ga-DOTATOC (1 case) and 18F-Fluoro-choline (1 case) (Figure 2). The range of SUV max in the lung lesions was 3-6 and the most frequent metabolic pattern was heterogeneus uptake, mainly subpleurally in both lungs. Chest CT COVID-19 findings were observed in 83% of the patients, and 27% had normal CT. 25 of the70 patients were confirmed as presenting SARS-CoV-2 infection with RT-PCR. In the remaining, it was not possible to confirm the presence of COVID-19

DISCUSSION:

The SARS-CoV-2 viral infection in asymptomatic PET-CT cancer patients is a rare possibility, but it represents a challenging scenario both for the diagnosis and also regarding the epidemiologic context. Our results confirm that the prevalence of SARS-CoV-2 infection is higher due to the relevant proportion of asymptomatic patients, some of them with lung disease, which can be diagnosed in a presymptomatic phase based on the incidental molecular imaging findings in procedures performed for completely different clinical indications.