Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The endotracheal and nasogastric tubes are in appropriate position . Opacity in the left lung base correlates with a small effusion and atelectasis on the CT performed 1 day prior . The effusion has decreased in size . No new opacities are concerning for pneumonia are identified . No pneumothorax . The cardiac and mediastinal contours are stable .
    OUTPUT:
    
1 . No new opacity concerning for pneumonia . 2 . Interval improvement of the small left pleural effusion .