Specificity of chest computed tomography in COVID-19-associated pneumonia: a retrospective study

Aim: To assess the specificity of COVID-19- associated pneumonia detection by radiologists using a chest CT scan.Materials and methods: From mid-February to early March 2020, 65 patients have been retrospectively selected from the Moscow City Clinical Hospital database; all of them had been treated in an inpatient facility with a verified diagnosis of COVID-19. In addition, 75 patients from the Unified Radiological Information Service have been randomly selected. In December 2019, these outpatients had been sent by an attending physician for a chest CT scan with suspected pneumonia. The imaging studies showed non-specific inflammation signs in the lungs. All 140 scans were analyzed by seven radiologists from different Russian cities, who independently categorized each study as “COVID-19” or “Other pneumonia”.Results: Chest computed tomography had a 92% specificity in the differential diagnosis of COVID-19-associated pneumonia, and its specificity in the general population is expected to be at least 80% with a high probability. The inter-rater variability was low (coefficient of variation for specificity 12.6%). The sensitivity in our study was 76.2%, and the coefficient of variation for sensitivity 23.5%. These findings are generally consistent with other studies. The primary study limitation is the absence of a sample with confirmed pneumonia caused by other viruses.Conclusion: Chest CT is highly specific for the detection of COVID-19-associated pneumonia.