Utility of Screening Chest Radiographs in Patients with Asymptomatic or Minimally Symptomatic COVID-19 in Singapore

BACKGROUND: Singapore saw an escalation of coronavirus disease 2019 (COVID-19) cases from under 4,000 in April 2020 to over 40,000 in June 2020 largely attributed to spread within shared facilities housing foreign workers. Appropriate triage and escalation of clinical care are critical for this patient group managed in community care facilities (CCFs). PURPOSE: To evaluate the imaging guideline recommendations for COVID-19 from the Fleischner Society and analyze the clinical utility of chest radiograph screening for asymptomatic or minimally symptomatic patients with COVID-19. MATERIALS AND METHODS: In this retrospective study, patients with COVID-19 confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) who were admitted to Singapore Expo, a designated CCF, for continuation of their management during May 3-31, 2020 were identified. Upon admission, patients aged 36 and older without any baseline chest imaging received a chest radiograph. All chest radiographs and clinical outcomes of patients including those who were subsequently transferred to acute hospitals for escalation of care were reviewed. Key proportions of patients with findings of pulmonary infection and those requiring further inpatient treatment were calculated, and 95% binomial proportion confidence intervals obtained using the Clopper-Pearson method. RESULTS: The study included 5,621 patients: all men 100% (5,621/5,621), mean age 37 ± 8 years (range 17-60). A total of 1,964 chest radiographs were performed of which normal accounted for 98.0% (1,925/1,964) and findings of pulmonary infection represented 2.0% (39/1,964). Only 0.2% (4/1,964) with chest radiograph findings of pulmonary infection (all of whom were symptomatic) required supplemental oxygenation and inpatient treatment. None of the asymptomatic patients with findings of pulmonary infection required supplemental oxygenation, and they received only symptomatic treatment. CONCLUSION: In accordance with Fleischner Society recommendations, chest radiograph screening for patients with COVID-19 aged 17-60 with mild or no symptoms is not indicated unless there is risk of clinical deterioration. See also the editorial by Schaefer-Prokop and Prokop.