Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left lung volume is decreased , likely the result of left lower lobe atelectasis . A small to moderate left pneumothorax may be slightly increased in size from the comparison CT , accounting for differences in technique . A left lung mass now contains a fiducial marker , with well - defined dense consolidation likely reflecting post - treatment change . The cardiac silhouette is unchanged in size , the mediastinal contours are unchanged . The right lung remains clear . The pulmonary vasculature is top normal , accounting for supine technique .
    OUTPUT:
    
Small - to moderate - sized left pneumothorax , perhaps slightly increased from comparison CT , allowing for differences in technique . Left lung post - treatment changes newly apparent , with associated lower lobe atelectasis . Findings were discussed with the patient 's PACU nurse at 2 : 15 p .m . at the time of discovery .