Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Overlying trauma board slightly limits assessment . The cardiac silhouette is normal in size . The mediastinal and hilar contours are unchanged . There are low lung volumes with patchy bibasilar airspace opacities , possibly reflective of atelectasis though infection is not excluded . There is crowding of the bronchovascular structures without overt pulmonary edema . No large pleural effusion or pneumothorax is is identified . There is a suggestion of subcutaneous emphysema within the left lateral chest wall . No displaced fractures are visualized . Remote right - sided posterior rib fractures are re - demonstrated .
    OUTPUT:
    
1 . Suggestion of subcutaneous emphysema in the left chest wall raises concern for a rib fracture though none are clearly seen . 2 . Low lung volumes . Bibasilar patchy opacities may reflect atelectasis but infection or aspiration is not excluded .