Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and CABG . The heart size is normal . Mediastinal and hilar contours are unremarkable . Lungs are clear except for minimal atelectasis at the lung bases . No pleural effusion or pneumothorax is seen . There are multilevel degenerative changes in the spine .
    OUTPUT:
    
Minimal bibasilar atelectasis . No radiographic evidence for pneumonia .