Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded . There is retrocardiac opacity which may reflect atelectasis or pneumonia in the right clinical setting . Interstitial lung markings likely reflect mild pulmonary vascular congestion . There is no pleural effusion or pneumothorax . The cardiomediastinal silhouette is moderate to severely enlarged .
    OUTPUT:
    
Retrocardiac opacity which may reflect atelectasis or pneumonia in the right clinical setting .