Comparison of the Main Staging Systems for Assessing the Severity of Lung Injury in Patients with COVID-19 and Evaluation of Their Predictive Value

Objective: to compare the results of staging the severity of viral pneumonia in patients with COVID-19 based on the results of chest computed tomography (CT) using the empirical visual scale CT 0–4 and chest CT severity score (CT-SS) point scale, as well as to assess their prognostic value.

Material and methods. Chest CT scans and anamnestic data in patients hospitalized to a non-specialized center repurposed for the treatment of new coronavirus infection, were analyzed. Chest CT analysis was performed by two radiologists using CT 0–4 and CT-SS scales.

Results. The time course of changes in the severity of lung parenchymal lesions, by using both scales, was found to be similar: the maximum magnitude of lung tissue changes was recorded on day 5 of the disease. In cases of death, there was a significantly more extensive lung parenchymal involvement at admission to the center than in recovered patients, which was also true for both CT data assessment systems. Bothscales demonstrated comparable diagnostic and prognostic value: there were no statistically significant differences in sensitivity, specificity, and predictive value of a fatal outcome. Both the CT 0–4 scales and the CT-SS are based on the estimation of the volume of the affected lung tissue, but when the CT 0–4 scale was employed, additional criteria were used in some cases: the presence of hydrothorax and the determination of the maximum score for the most affected lung. Not all patients with a pronounced CT picture of viral pneumonia had a fatal outcome, which may indicate the presence of other factors that increase its risk.

Conclusion. Both CT 0–4 and CT-SS scales have similar predictive values. The greater severity of parenchymal damage assessed by these CT scales was associated with the higher mortality rate.

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