Radiologists showed high specificity but moderate sensitivity in differentiating COVID-19 from viral pneumonia on chest CT. Three Chinese radiologists had sensitivities of 72%, 72%, and 94% with specificities of 94%, 88%, and 24%, while four U.S. radiologists had sensitivities of 93%, 83%, 73%, and 73% with specificities of 100%, 93%, 93%, and 100%. The most distinguishing features of COVID-19 pneumonia included peripheral distribution, ground-glass opacity, and vascular thickening. The study aimed to assess the performance of U.S. and Chinese radiologists in differentiating COVID-19 from viral pneumonia on chest CT. A total of 424 patients were reviewed, including 205 with non-COVID-19 pneumonia and 219 with COVID-19. The results showed that radiologists could accurately differentiate between the two conditions with high specificity but moderate sensitivity. The study highlights the importance of chest CT in diagnosing COVID-19, especially when RT-PCR results are inconclusive. However, the low specificity of chest CT in some cases can lead to misdiagnosis. The study also emphasizes the need for further research and the development of AI tools to improve diagnostic accuracy. The limitations of the study include a small sample size and potential selection bias. Overall, the study concludes that radiologists can effectively differentiate between COVID-19 and viral pneumonia on chest CT with high specificity but moderate sensitivity.Radiologists showed high specificity but moderate sensitivity in differentiating COVID-19 from viral pneumonia on chest CT. Three Chinese radiologists had sensitivities of 72%, 72%, and 94% with specificities of 94%, 88%, and 24%, while four U.S. radiologists had sensitivities of 93%, 83%, 73%, and 73% with specificities of 100%, 93%, 93%, and 100%. The most distinguishing features of COVID-19 pneumonia included peripheral distribution, ground-glass opacity, and vascular thickening. The study aimed to assess the performance of U.S. and Chinese radiologists in differentiating COVID-19 from viral pneumonia on chest CT. A total of 424 patients were reviewed, including 205 with non-COVID-19 pneumonia and 219 with COVID-19. The results showed that radiologists could accurately differentiate between the two conditions with high specificity but moderate sensitivity. The study highlights the importance of chest CT in diagnosing COVID-19, especially when RT-PCR results are inconclusive. However, the low specificity of chest CT in some cases can lead to misdiagnosis. The study also emphasizes the need for further research and the development of AI tools to improve diagnostic accuracy. The limitations of the study include a small sample size and potential selection bias. Overall, the study concludes that radiologists can effectively differentiate between COVID-19 and viral pneumonia on chest CT with high specificity but moderate sensitivity.