Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The right lung is well expanded and clear . A small left pleural effusion is present . Left lower lobe opacity is noted adjacent to the effusion . Mediastinal contours , hila , and cardiac silhouette are normal .
    OUTPUT:
    
Small left pleural effusion with adjacent parenchymal opacity which could be due to atelectasis or pneumonia .