Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low , resulting in crowding of the bronchovascular structures . Retrocardiac opacity is likely atelectasis . Heart is top - normal in size . No pulmonary edema . Mediastinal and hilar contours are unremarkable . No free air under the diaphragm .
    OUTPUT:
    
1 . No free air under the diaphragm . 2 . Retrocardiac opacity is likely atelectasis .