Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are low in volume with right middle lobe opacification , similar to the subsequently obtained chest CT . This could be due to collapse , but superinfection or concomitant infection can not be excluded . No pneumothorax is seen on these images . The heart is top normal in size with normal mediastinal contours .
    OUTPUT:
    
Right middle lobe opacification as on subsequent CT could reflect collapse or pneumonia .