Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded and show mild left lower lobe opacity . The cardiac silhouette is mildly enlarged . The mediastinal silhouette and hilar contours are normal . There are small bilateral effusions . The hilar contours are normal .
    OUTPUT:
    
Left lower lobe opacity could represent atelectasis or pneumonia with a small associated effusion .