Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Bilateral lung volumes are low . Endotracheal tube tip is 5 .5 cm above the carina , orogastric tube ends into the stomach , and left subclavian line tip is in mid SVC . Increased retrocardiac opacity is better since yesterday . Mild to moderately enlarged heart size is stable , and mediastinal and hilar contours are unremarkable . No discrete opacities in right lung .
    OUTPUT:
    
Mild retrocardiac opacity , decreased since yesterday , either atelectasis or aspiration . Associated infection can not be ruled out . No new focal opacities in the right lung .