Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac , mediastinal and hilar contours are unchanged , with heart size within normal limits . Linear opacities in both lung bases likely reflect subsegmental atelectasis and / or scarring . No focal consolidation , pleural effusion , or pneumothorax is present . Old right - sided rib fractures are present . There are mild degenerative changes of the thoracic spine .
    OUTPUT:
    
Bibasilar atelectasis and / or scarring . Otherwise , no radiographic evidence for pneumonia .