Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There are low lung volumes . Heart size is normal with a left ventricular predominance . The mediastinal and hilar contours are unremarkable . There is crowding of the bronchovascular structures but no overt pulmonary edema is present . Patchy bibasilar airspace opacities may reflect atelectasis though infection or aspiration can not be completely excluded . No pleural effusion or pneumothorax is seen . There are multilevel degenerative changes in the thoracic spine .
    OUTPUT:
    
Low lung volumes with patchy bibasilar opacities possibly reflecting atelectasis but infection or aspiration can not be excluded .