Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . The heart size is mildly enlarged . The mediastinal contours are unchanged , with mild tortuosity of the thoracic aorta again noted . The aorta is diffusely calcified . There is crowding of the bronchovascular structures without overt pulmonary edema demonstrated . Patchy opacities in the lung bases likely reflect areas of atelectasis . Pneumonia , however , can not be completely excluded . No pleural effusion or pneumothorax is seen . There are no acute osseous abnormalities .
    OUTPUT:
    
Low lung volumes . Patchy bibasilar airspace opacities likely reflect areas of atelectasis but infection is not excluded .