Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patchy opacity in the right middle lobe appears only slightly increased compared to earlier studies from ___ and ___ , most suggestive of atelectasis . There is no pleural effusion or pneumothorax . The cardiac , mediastinal , and hilar contours are unchanged .
    OUTPUT:
    
Slightly increased patchy right lower lung opacity , although probably attributable to waxing and waning atelectasis rather than pneumonia .