Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac , mediastinal , and hilar contours are unchanged , with the heart size within normal limits . There are low lung volumes . This causes crowding of the bronchovascular structures . There is no focal consolidation , pleural effusion , or pneumothorax , with mild atelectatic changes noted at the lung bases . No acute osseous abnormalities are seen . No definite free air is seen under the diaphragms .
    OUTPUT:
    
No free air noted under the diaphragms . Low lung volumes with mild bibasilar atelectasis .