Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes remain low . Large - to - moderate right - sided pleural effusion persists despite the presence of a pigtail catheter which appears unchanged in position , projecting over the right lower hemithorax . Adjacent platelike atelectasis and scarring is minimally worse . Probable small left pleural effusion as well as atelectasis is overall similar . No pneumothorax . Heart size and mediastinum are probably overall unchanged . The ICD is unchanged .
    OUTPUT:
    
Persistent moderate right pleural effusion despite presence of pigtail drain over the last several days .