Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and CABG . Posterior rod and screw fixation hardware in the lower cervical spine is again noted . The heart size is at the upper limits of normal . The mediastinal and hilar contours are within normal limits . The lungs demonstrate bibasilar airspace opacities . There is currently no pleural effusion or pneumothorax . An old posterlateral rib fracture is present in the left upper rib cage .
    OUTPUT:
    
Bibasilar opacities , likely atelectasis . Aspiration or pneumonia can not be completely excluded .