Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . Cardiac , mediastinal and hilar contours are unchanged . Heart size is normal . There is crowding of the bronchovascular structures , but no pulmonary edema is demonstrated . Linear and streaky opacities in the lung bases likely reflect atelectasis in the setting of low lung volumes . No definite pleural effusion or pneumothorax is identified . Degenerative changes are again noted throughout the thoracic spine .
    OUTPUT:
    
Low lung volumes with probable bibasilar atelectasis .