Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are somewhat low in volume . Retrocardiac opacity is not well located on the lateral view but is concerning for left lower lobe pneumonia or aspiration . There is no pleural effusion or pneumothorax . The heart is normal in size with normal mediastinal and hilar contours .
    OUTPUT:
    
Left lower lobe opacity concerning for aspiration or pneumonia .