Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Comparison is made to previous study from two and a half hours earlier . There has been placement of pigtail catheter in the left chest . There has been improved aeration of the left lung . There remains a moderate sized apical and basilar pneumothoraces . The right lung appears clear . Heart size is within normal limits .
    OUTPUT:
    
Improved expansion of the left lung , with persistent moderate size pneumothorax .