Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The large left pleural effusion has slightly decreased following pigtail catheter drainage . Associated left lower lobe collapse is unchanged . Left lung volumes remain low . The right lung is clear . There is no pneumothorax . The cardiomediastinal silhouette is stable .
    OUTPUT:
    
Slightly decreased large left pleural effusion following pigtail catheter drainage . Stable left lower lobe collapse .