Interobserver Agreement in Semi-Quantitative Scale-Based Interpretation of Chest Radiographs in COVID-19 Patients

BACKGROUND The chest X-ray is the most available imaging modality enabling semi-quantitative evaluation of pulmonary involvement. Parametric evaluation of chest radiographs in patients with SARS-CoV-2 infection is crucial for triage and therapeutic management. The CXR Score (Brixia Score), SARI CXR Severity Scoring System, and Radiographic Assessment of Lung Edema (RALE), proposed to evaluate SARS-CoV-2 infiltration of the lungs, were analyzed for interobserver agreement. MATERIAL AND METHODS This study analyzed 200 chest X-rays from 200 consecutive patients with confirmed SARS-CoV-2 infection, hospitalized at the Central Clinical Hospital of the Ministry of the Interior and Administration in Warsaw. Radiographs were evaluated by 2 radiologists according to 3 scales: SARI, RALE, and CXR Score. RESULTS The overall interobserver agreement for SARI ratings was good (kappa=0.755; 95% CI, 0.817-0.694), for RALE scale assessments it was very good (kappa=0.818; 95% CI, 0.844-0.793), and for CXR scale assessments it was very good (kappa=0.844; 95% CI, 0.846-0.841). A moderate correlation was found between the radiological image assessed using each of the scales and the clinical condition of the patient in MEWS (Modified Early Warning Score) (r=0.425-0.591). CONCLUSIONS The analyzed scales are characterized by good or very good interobserver agreement of assessments of the extent of pulmonary infiltration. Since the CXR Score showed the strongest correlation with the clinical condition of the patient as expressed using the MEWS scale, it is the preferred scale for chest radiograph assessment of patients with COVID-19 in the light of data provided.