Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy , aortic valve replacement , and coronary artery bypass graft surgery . Heart size is normal . The mediastinal and hilar contours are unremarkable . Pulmonary vascularity is within normal limits . Streaky opacity within the right lung base is most likely reflective of atelectasis , though early infection can not be completely excluded . No pleural effusion or pneumothorax is present . Calcified granuloma measuring 2 - 3 mm within the right upper lung field is unchanged . No pleural effusion or pneumothorax is seen . There are multilevel degenerative changes in the thoracic spine .
    OUTPUT:
    
Minimal streaky opacity in the right lung base may reflect atelectasis , though infection can not be completely excluded .