Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes continue be low with bibasilar atelectasis . A retrocardiac opacity seen on the lateral radiograph likely represents atelectasis , though infection can not be fully excluded . There are no pleural effusions or pulmonary edema . The heart is normal in size , and the mediastinal contours are normal .
    OUTPUT:
    
Low lung volumes with bibasilar atelectasis . Retrocardiac opacity likely represents atelectasis , though pneumonia can not be excluded .