Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Two PA and one lateral chest radiographs were obtained . Compared to the prior study three days ago , there has been improved aeration of the pulmonary opacity in the left anterior lateral base . Minimal atelectasis and small effusion at the right knee are unchanged . Diaphragm flattening consistent with COPD is unchanged . No new consolidation , effusion , or pneumothorax is present . The cardiac and mediastinal contours are normal . Degenerative changes in the thoracic spine and wedge deformity of T7 are unchanged .
    OUTPUT:
    
Improved aeration at the left base over the last three days .