Radiographic features of COVID-19 based on an initial cohort of 96 patients in Singapore

Singapore Med J. 2021 Sep;62(9):458-465. doi: 10.11622/smedj.2020142. Epub 2020 Sep 21.

Abstract

Introduction: Chest radiographs (CXRs) are widely used for the screening and management of COVID-19. This article describes the radiographic features of COVID-19 based on an initial national cohort of patients.

Methods: This is a retrospective review of swab-positive patients with COVID-19 who were admitted to four different hospitals in Singapore between 22 January and 9 March 2020. Initial and follow-up CXRs were reviewed by three experienced radiologists to identify the predominant pattern and distribution of lung parenchymal abnormalities.

Results: In total, 347 CXRs of 96 patients were reviewed. Initial CXRs were abnormal in 41 (42.7%) out of 96 patients. The mean time from onset of symptoms to CXR abnormality was 5.3 ± 4.7 days. The predominant pattern of lung abnormality was ground-glass opacity on initial CXRs (51.2%) and consolidation on follow-up CXRs (51.0%). Multifocal bilateral abnormalities in mixed central and peripheral distribution were observed in 63.4% and 59.2% of abnormal initial and follow-up CXRs, respectively. The lower zones were involved in 90.2% of initial CXRs and 93.9% of follow-up CXRs.

Conclusion: In a cohort of swab-positive patients, including those identified from contact tracing, we found a lower incidence of CXR abnormalities than was previously reported. The most common pattern was ground-glass opacity or consolidation, but mixed central and peripheral involvement was more common than peripheral involvement alone.

Keywords: SARS-CoV-2; chest radiographs; coronavirus disease 2019.

MeSH terms

  • COVID-19*
  • Humans
  • Lung / diagnostic imaging
  • Radiography, Thoracic
  • Retrospective Studies
  • SARS-CoV-2
  • Singapore