Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Again , there is a small left apical pneumothorax , which allowing for slight differences in positioning , is not substantially changed . A left pleural pigtail drainage catheter is in place . Scarring , sutures , and atelectasis in the left upper lobe are stable . The lungs are otherwise clear . There is no right pneumothorax . There is no pleural effusion . The cardiomediastinal silhouette is normal .
    OUTPUT:
    
No substantial change in the small left apical pneumothorax .