Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There has been interval placement of a right pigtail catheter . The previously seen large pneumothorax has markedly decreased in size . The cardiomediastinal silhouette is normal . The left lung is clear . Right lower lobe atelectasis persists .
    OUTPUT:
    
Interval placement of a right pigtail catheter and decrease in size of the previously large right pneumothorax .