Chest x-ray severity score in COVID-19 patients on emergency department admission: a two-centre study

Cristian Giuseppe Monaco, Federico Zaottini, Simone Schiaffino, Alessandro Villa, Gianmarco Della Pepa, Luca Alessandro Carbonaro, Laura Menicagli, Andrea Cozzi, Serena Carriero, Francesco Arpaia, Giovanni Di Leo, Davide Astengo, Ilan Rosenberg, Francesco Sardanelli

Research output: Contribution to journalArticlepeer-review


Background: Integration of imaging and clinical parameters could improve the stratification of COVID-19 patients on emergency department (ED) admission. We aimed to assess the extent of COVID-19 pulmonary abnormalities on chest x-ray (CXR) using a semiquantitative severity score, correlating it with clinical data and testing its interobserver agreement. Methods: From February 22 to April 8, 2020, 926 consecutive patients referring to ED of two institutions in Northern Italy for suspected SARS-CoV-2 infection were reviewed. Patients with reverse transcriptase-polymerase chain reaction positive for SARS-CoV-2 and CXR images on ED admission were included (295 patients, median age 69 years, 199 males). Five readers independently and blindly reviewed all CXRs, rating pulmonary parenchymal involvement using a 0–3 semiquantitative score in 1-point increments on 6 lung zones (range 0–18). Interobserver agreement was assessed with weighted Cohen’s κ, correlations between median CXR score and clinical data with Spearman’s ρ, and the Mann-Whitney U test. Results: Median score showed negative correlation with SpO2 (ρ = -0.242, p < 0.001), positive correlation with white cell count (ρ = 0.277, p < 0.001), lactate dehydrogenase (ρ = 0.308, p < 0.001), and C-reactive protein (ρ = 0.367, p < 0.001), being significantly higher in subsequently dead patients (p = 0.003). Considering overall scores, readers’ pairings yielded moderate (κ = 0.449, p < 0.001) to almost perfect interobserver agreement (κ = 0.872, p < 0.001), with better interobserver agreement between readers of centre 2 (up to κ = 0.872, p < 0.001) than centre 1 (κ = 0.764, p < 0.001). Conclusions: Proposed CXR pulmonary severity score in COVID-19 showed moderate to almost perfect interobserver agreement and significant but weak correlations with clinical parameters, potentially furthering CXR integration in patients’ stratification.

Original languageEnglish
Article number68
JournalEuropean radiology experimental
Issue number1
Publication statusPublished - Dec 2020


  • Chest x-ray
  • COVID-19
  • COVID-19 diagnostic testing
  • Diagnostic imaging
  • Severity score

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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