Uncertainty in using chest computed tomography in early coronavirus disease (COVID-19).

To the Editor,

The title of a recent Images article in the Journal by Chen et al.1 describes chest computed tomography (CT) findings in a pregnant woman with coronavirus disease (COVID-19) as “early coronavirus disease.” We argue that these findings are inconsistent with “early” COVID-19. Cases of COVID-19 were identified in Thailand shortly after its first appearance in China2; as of 14 March 2020, there have been 82 confirmed diagnoses of COVID-19 reported in Thailand. All Thai cases are confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) in two reference labs, and all patients receive chest CT scans. Thirty-eight of the 82 cases were diagnosed during active screening for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in persons who had been in close contact to patients known to have COVID-19. Most of those screened were asymptomatic or reported only mild symptoms; none showed abnormal findings on chest CT scans. One asymptomatic Thai patient underwent general anesthesia for orthopedic surgery before being diagnosed with COVID-19 in the postoperative period. This case also had normal CT findings at the time of diagnosis.

Hu et al. reported that 29.2% of asymptomatic patients from China who were infected with SARS-CoV-2 and who presented with no or mild symptoms at the time of diagnosis by RT-PCR test had a normal chest CT scan.3 Asymptomatic SARS-CoV-2 infection is possible and has been previously reported in Thailand and Croatia.4 COVID-19 may be asymptomatic in its early stages even though viral RNA can be detected by RT-PCR screening.4 We therefore discourage the consideration of CT findings when ruling out cases of COVID-19.