Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is enlarged , similar to prior . Prominent bilateral hilar markings are consistent with pulmonary artery enlargement . Left pleural effusion has decreased in size over the interval , and is now small in size . Retrocardiac opacity may represent compressive atelectasis or aspiration , however pneumonia could be considered in the appropriate clinical setting . No pneumothorax .
    OUTPUT:
    
1 . Small left pleural effusion . 2 . Retrocardiac opacity may represent compressive atelectasis or aspiration , however pneumonia could be considered in the appropriate clinical setting .