Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Redemonstrated is a pigtail catheter within the right hemithorax . There is a residual right apical pneumothorax , slightly enlarged since the most recent comparison . Redemonstrated is opacity in the right lung base , which may reflect residual atelectasis .
    OUTPUT:
    
1 . Persistent , small right sided pneumothorax , slightly enlarged since the most recent examination .