Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . Relatively unchanged appearance of a confluent left lower lobe airspace opacity , in addition to right middle lobe airspace opacities . The bilateral upper lungs are grossly clear . There is no large pleural effusion or pneumothorax . The cardiomediastinal silhouette is unchanged in appearance .
    OUTPUT:
    
Left lower and right middle lobe airspace opacities , compatible with persistent underlying pneumonia .