key: cord-0728198-j1hhmkti
authors: Jalaber, C.; Chassagnon, G.; Hani, C.; Dangeard, S.; Babin, M.; Launay, O.; Revel, M-P.
title: Is COVID-19 Pneumonia differentiable from other viral pneumonia on CT scan?
date: 2021-04-27
journal: Respir Med Res
DOI: 10.1016/j.resmer.2021.100824
sha: 20b1fe9496149dd3a35eaab7d62438fc09cb6fe7
doc_id: 728198
cord_uid: j1hhmkti

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used as a fast and effective method for the diagnosis of Coronavirus Disease 2019 pneumonia (1) . The typical CT features of COVID-19 pneumonia have been largely reported and mention bilateral ground-glass opacities predominating in the subpleural, posterior and basal parts of the lungs as main CT findings (2) . Over time, ground-glass opacities tend to transform into crazy paving areas and are progressively replaced by linear consolidation or other patterns of organizing pneumonia (2) (3) (4) . Regarding CT diagnostic performance for COVID-19 pneumonia, a metaanalysis including 31 studies reported a pooled sensitivity of chest CT in suspected COVID-19 participants of 89.9% and a pooled specificity of only 61.1% (5) . False positives usually result from other pulmonary infections, pulmonary edema or fibrotic interstitial lung diseases which also include ground glass opacities as predominant CT feature. Apart from COVID-19, CT characteristics of other viral pneumonias are more diverse, especially depending on the immune status of the host (6), but they have been less extensively described since CT is not largely performed in immunocompetent patients. The purpose of our study was to assess the performance of French radiologists in differentiating COVID-19 from other viral pneumonia by chest CT.

Using computed our hospital information system, we retrospectively included patients referred for (Table 1) . Lastly, each radiologist had to determine whether the chest CT scan was suggestive of COVID-19 pneumonia or other viral pneumonia. A generalized linear model was used to identify the association between each CT feature and the diagnosis of COVID-19 or other viral pneumonia. In case of discordance between the 5 radiologists for the presence of a CT feature, it was considered to be present if found by at least 3 of the readers.

The CT features that were the most strongly associated with COVID-19 pneumonia were bands of The five radiologists had an averaged sensitivity of 96.7% (range= 91.1 to 100%) for COVID-19 pneumonia diagnosis whereas all had 100% specificity. The averaged accuracy was 98% (range= 94 to 100%). The sensitivity and specificity of CT reading by French radiologists to differentiate between COVID-19 and other viral pneumonia in our study were higher than that previously reported for radiologists from the United States and China, who had a sensitivity of 70% and a specificity of 84% (7) . This might be due to the availability from March 2020 of a structured report for COVID-19 pneumonia on the website of the French Society of Radiology, highlighting CT features in favor and against the diagnosis of COVID-19 (8).

Our study has several limitations. First, in view of the rarity of symptomatic viral pneumonias requiring chest CT in immunocompetent patients, it was not possible to collect a large number of non-COVID-19 cases, resulting in an uneven number of CT scans in the two categories, COVID-19 and non-COVID- 3 (4%) 0 (0%) 3 (11%) -<10% 32 (46%) 8 (20%) 24 (86%) -10-25% 22 (32%) 21 (51%) 1 (4%) -25-50% 11 (16%) 11 (27%) 0 (0%) -50-75% 1 (1%) 1 (2%) 0 (0%) ->75% 0 (0%) 0 (0%) 0 (0%)

The Role of Chest Imaging in Patient Management During the COVID-19 Pandemic

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Chest CT in COVID-19 pneumonia: A review of current knowledge. Diagnostic and Interventional Imaging

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Performance of Radiologists in Differentiating COVID-19 from Non-COVID-19 Viral Pneumonia at Chest CT