Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a left lower lobe retrocardiac opacity , better delineated on CT from the same day . Otherwise , there is no effusion or pneumothorax . Cardiomediastinal silhouette is normal . No acute fractures are identified .
    OUTPUT:
    
There is a left lower lobe retrocardiac opacity , better delineated on CT from the same day .