Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A left chest tube is unchanged . Since the prior exam , the amount of pleural fluid has significantly decreased . A small left apical pneumothorax is unchanged . Moderate subcutaneous emphysema is again noted and unchanged . Aeration at the left base has also improved with the reduction in size of the pleural effusion . The rounded opacity in the left upper lung is stable in size with persistent collapse of the left upper lobe around the mass . The right lung is essentially clear . The cardiomediastinal silhouette is normal .
    OUTPUT:
    
Decrease in size of the left pleural effusion and improved aeration at the left base . A small apical left pneumothorax and the upper lobe mass are not significantly changed since the prior exam .