Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well inflated . A retrocardiac opacity corresponds with a left lower lobe opacity on the lateral view , compatible with pneumonia . The right lung is clear . Cardiomediastinal silhouettes are normal . No pneumothorax or pleural effusion .
    OUTPUT:
    
Retrocardiac , left lower lobe opacity is concerning for pneumonia .