Objectives: The severity of pulmonary Covid-19 infection can be assessed by the pattern and extent of parenchymal involvement observed in computed tomography (CT), and it is important to standardize the analysis through objective, practical, and reproducible systems. We propose a method for stratifying the radiological severity of pulmonary disease, the Radiological Severity Score (RAD-Covid Score), in Covid-19 patients by quantifying infiltrate in chest CT, including assessment of its accuracy in predicting disease severity. Methods: : This retrospective, single-center study analyzed patients with a confirmed diagnosis of Covid-19 infection by real-time reverse-transcriptase polymerase chain reaction, who underwent chest CT at hospital admission between March 6 and April 6, 2020. The CT scans were classified as positive, negative or equivocal, and a radiological severity score (RADCovid Score) was assigned. Clinical severity was assessed upon hospital admission, with mild cases considered suitable for home treatment, moderate cases for hospital admission and severe cases for intensive care unit admission. Results: : 658 patients were included. Concordance correlation coefficient for the RAD-Covid Score was almost perfect among observers (0.833), with an overall agreement of 89.5%. The RAD-Covid Score was positively correlated with clinical severity and death, i.e., the higher the RAD-Covid Score, the greater the chance of a more severe clinical condition and mortality. This association proved independent of age and comorbidities. Accuracy of this score was 71%. Conclusions: : The RAD-Covid Score showed good accuracy in predicting clinical severity at hospital admission and mortality in patients with confirmed Covid-19 infection and was an independent predictor of severity.
Tomographic score (RAD-Covid Score) to assess the clinical severity of infection with the novel Coronavirus