Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP and lateral views of the chest compared to previous exam from ___ . Linear opacity at the right lung base may represent atelectasis . There is also , however , blunting of the lateral costophrenic angle suggestive of an effusion . Elsewhere , the lungs are clear . Please note that the lateral view is limited secondary to patient 's arms down by his side . Cardiac silhouette is enlarged but stable in configuration . Osseous and soft tissue structures are unchanged .
    OUTPUT:
    
Linear opacity at the right lung base most suggestive of atelectasis ; however , infection can not be entirely excluded . Possible small right pleural effusion .