Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Again seen is widespread lucency throughout the upper zones , denoting COPD . No pneumothorax is detected . A subtle right lower lobe lung mass measuring up to 6 .5 cm is again seen , unchanged in configuration . Mild pulmonary edema has improved since ___ . There is no large effusion . The hilar and mediastinal contours remain stable .
    OUTPUT:
    
1 . No pneumothorax . 2 . Right lower lobe mass , better visualized on the CT examination . 3 . Improved mild pulmonary edema .