The top two chest x-ray images from the original research article "Coronavirus Disease (COVID-19): The Value of Chest Radiography for Patients Greater Than Age 50 Years at an Earlier Timepoint of Symptoms Compared With Younger Patients" (doi: 10.31486/toj.20.0102) show findings characteristic of COVID-19: bilateral patchy or confluent band-like ground glass opacity or consolidation in a peripheral and mid-to-lower lung zone distribution.
The image on the lower left shows an atypical x-ray that the authors classified as suspicious for COVID-19, with some, but not all, of the characteristic findings. The image on the lower right is also atypical, but the findings are suggestive of a diagnosis other than COVID-19, in this case, subsegmental atelectasis.
Based on their evaluation of 60 x-rays, the authors suggest that radiographic findings in patients >50 years within 1 week of symptom onset can be useful for early diagnosis of COVID-19.