Background: Multicenter retrospective comparison of the first high-resolution computed tomography (HRCT) findings of coronavirus disease 2019 (COVID-19) and other viral pneumonias.Methods: We retrospectively collected clinical and imaging data from 254 cases of confirmed viral pneumonia in 20 hospitals in Yunnan Province, China, from March 1, 2015, to March 15, 2020. According to the virus responsible for the pneumonia, the pneumonias were divided into non-COVID-19 (133 cases) and COVID-19 (121

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... cases). The non-COVID-19 pneumonias included 3 types: cytomegalovirus (CMV) (31 cases), influenza A virus (82 cases), and influenza B virus (20 cases). The differences in the basic clinical characteristics, lesion distribution, location and imaging signs among the four viral pneumonias were analyzed and compared.Results: Fever and cough were the most common clinical symptoms of the four viral pneumonias. Compared with the COVID-19 patients, the non-COVID-19 patients had higher proportions of fatigue, sore throat, expectorant and chest tightness (all p<0.000). In addition, in the CMV pneumonia patients, the proportion of patients with combined acquired immunodeficiency syndrome (AIDS) and leukopenia were high (all p<0.000). Comparisons of the imaging findings of the four viral pneumonias showed that pulmonary lesions of COVID-19 were more likely to occur in the peripheral and lower lobes of both lungs, while those of CMV pneumonia were diffusely distributed. Compared with the non-COVID-19 pneumonias, COVID-19 pneumonia was more likely to present as ground-glass opacity (GGO), intralobular interstitial thickening, vascular thickening and halo sign (all p<0.05). In addition, in the early stage of COVID-19, extensive consolidation, fibrous stripes, subpleural lines, crazy-paving pattern, tree-in-bud, mediastinal lymphadenectasis, pleural thickening and pleural effusion were rare (all p<0.05).Conclusion: The HRCT findings of COVID-19 pneumonia and other viral pneumonias overlapped significantly, but many important differential imaging features could still be observed.