Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: As compared to prior chest radiograph , there has been interval improvement of a large left pneumothorax . The apical visceral pleural line is at the level of the inferior aspect of the left third posterior rib . There is a small loculated hyropneumothorax . Pigtail catheter remains in place in the left hemithorax . Right lung is clear . The cardiomediastinal contours are within normal limits and are midline .
    OUTPUT:
    
Improving left pneumothorax .