Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal in size . The mediastinal and hilar contours appear stable . A chronic opacity in the right upper lobe appears unchanged on the frontal view although more compact and dense on the later view . Elsewhere , the lungs appear clear . The chest is mildly hyperinflated . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Increased degree of volume loss associated with chronic right upper lobe area of atelectasis or scarring , which may reflect waxing and waning atelectasis . Superimposed infection is not entirely excluded , however .