Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Persisting retrocardiac opacity however there has been interval decrease in the extent of the patchy opacities in the right lung base . No right pleural effusion or pneumothorax identified . The size the cardiac silhouette is enlarged but unchanged .
    OUTPUT:
    
Persisting retrocardiac opacity . Improved aeration of the right lung base .