Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Endotracheal tube tip is 4 .4 cm above the carina and a feeding tube ends into the stomach , appropriately positioned . Over the last 24 hours , left lower lung and retrocardiac opacity reflecting left lower lung volume loss has improved . Pleural effusion if any is small and presumed on the left side . There is no pulmonary edema . Mildly enlarged heart size , mediastinal and hilar contours have mostly stable appearance .
    OUTPUT:
    
Left lower lung and retrocardiac opacity improved over last 24 hours , is likely a combination of atelectasis and small effusion . No new opacities in the lungs .