18F-Fluorocholine uptake matching CT lesions in the lungs of a patient clinically cured from COVID-19 syndrome.

A 76-year-old man was referred to 18F-fluorocholine (FCH) PET/CT for biochemical recurrence of prostate cancer (BRPC) after prostatectomy in 2004 (initial TNM: pT2bN0). Prostate-specific antigen (PSA) serum levels had been slowly rising (from 0.1 ng/mL in 2015 to 0.31 ng/mL in 2020).

This patient presented with fever and cough 1 month before, considered as highly consistent with a COVID-19 infection by his general practitioner [1] and a positive antibody testing confirmed the infection (immunoglobulin G = 7.67, positive if > 1.4).

At the time of FCH PET-CT, he has been asymptomatic for over 1 week, and still is 2 months later.

One hour after intravenous injection of 210 MBq of FCH, no focus evocative of BRPC was found. However, bilateral pulmonary foci were discovered (SUVmax 3.9). On CT, they matched ground-glass opacities and multifocal patchy consolidative opacities involving approximately 30% of the lungs, predominating in the peripheral inferior and posterior regions: typical CT features of COVID-19 infection [1-3]. Bilateral mediastinum lymph nodes also took up FCH (SUVmax 3.8). All these lesions were not visible on a previous FCH PET-CT performed in 2018.

COVID-19-induced lung lesions may take up 18F-fluorodeoxyglucose [4, 5] and 18F-fluorocholine as in this case. FCH was already known to reveal inflammatory conditions [6-8]. FCH uptake by mediastinum lymph nodes is frequent but this usual pattern differs from the present images.

The significance of those metabolically active lesions in a patient who clinically recovered from a COVID-19 infection is unknown: healing with a risk of lung fibrosis or subacute evolution with a risk of recurrence which did not occur within 2 months and of contamination? Male sex is associated with prolonged SARS-CoV-2 RNA shedding [9]; thus, other cases of COVID-19 imaging patterns are likely to be discovered on FCH PET/CT in the future.