Chest x-ray in the COVID-19 pandemic: Radiologists' real-world reader performance

Eur J Radiol. 2020 Nov;132:109272. doi: 10.1016/j.ejrad.2020.109272. Epub 2020 Sep 10.

Abstract

Purpose: To report real-world diagnostic performance of chest x-ray (CXR) readings during the COVID-19 pandemic.

Methods: In this retrospective observational study we enrolled all patients presenting to the emergency department of a Milan-based university hospital from February 24th to April 8th 2020 who underwent nasopharyngeal swab for reverse transcriptase-polymerase chain reaction (RT-PCR) and anteroposterior bedside CXR within 12 h. A composite reference standard combining RT-PCR results with phone-call-based anamnesis was obtained. Radiologists were grouped by CXR reading experience (Group-1, >10 years; Group-2, <10 years), diagnostic performance indexes were calculated for each radiologist and for the two groups.

Results: Group-1 read 435 CXRs (77.0 % disease prevalence): sensitivity was 89.0 %, specificity 66.0 %, accuracy 83.7 %. Group-2 read 100 CXRs (73.0 % prevalence): sensitivity was 89.0 %, specificity 40.7 %, accuracy 76.0 %. During the first half of the outbreak (195 CXRs, 66.7 % disease prevalence), overall sensitivity was 80.8 %, specificity 67.7 %, accuracy 76.4 %, Group-1 sensitivity being similar to Group-2 (80.6 % versus 81.5 %, respectively) but higher specificity (74.0 % versus 46.7 %) and accuracy (78.4 % versus 69.0 %). During the second half (340 CXRs, 81.8 % prevalence), overall sensitivity increased to 92.8 %, specificity dropped to 53.2 %, accuracy increased to 85.6 %, this pattern mirrored in both groups, with decreased specificity (Group-1, 58.0 %; Group-2, 33.3 %) but increased sensitivity (92.7 % and 93.5 %) and accuracy (86.5 % and 81.0 %, respectively).

Conclusions: Real-world CXR diagnostic performance during the COVID-19 pandemic showed overall high sensitivity with higher specificity for more experienced radiologists. The increase in accuracy over time strengthens CXR role as a first line examination in suspected COVID-19 patients.

Keywords: COVID-19; Pneumonia, viral; Radiography, thoracic; Severe acute respiratory syndrome coronavirus 2.

Publication types

  • Observational Study

MeSH terms

  • Betacoronavirus
  • COVID-19
  • Clinical Competence / statistics & numerical data*
  • Coronavirus Infections / diagnostic imaging*
  • Female
  • Humans
  • Lung / diagnostic imaging
  • Male
  • Middle Aged
  • Pandemics
  • Pneumonia, Viral / diagnostic imaging*
  • Radiography, Thoracic / methods*
  • Radiography, Thoracic / standards
  • Radiologists / standards
  • Reproducibility of Results
  • Retrospective Studies
  • SARS-CoV-2
  • Sensitivity and Specificity