Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A small right pneumothorax is again seen , which , allowing for differences in image in technique , is not appreciably changed since the ___ CT . The heart size is top normal . The hilar and mediastinal contours are within normal limits . There is no left pneumothorax . There is no pleural effusion .
    OUTPUT:
    
Small right pneumothorax is unchanged since ___ . No pleural effusion or left pneumothorax .