Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lung volumes are low which appears to exaggerate the cardiomediastinal structures . There mild is bibasilar atelectasis . No definite pneumothorax is identified . There is no large pleural effusion . The rib fractures seen on the prior CT are not definitely seen on this exam .
    OUTPUT:
    
Limited study due to low lung volumes . No pneumothorax .