Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and CABG . Heart size remains mildly enlarged . The mediastinal contours are unchanged with tortuosity of the thoracic aorta again noted . The right PICC has been removed . Pulmonary vasculature is normal . Lung volumes are low . Patchy opacities in the lung bases may reflect areas of atelectasis . No pleural effusion or pneumothorax is present , but assessment of the lung apices is limited as the patient 's soft tissues of the neck project over and obscure these regions . No acute osseous abnormality is identified .
    OUTPUT:
    
Low lung volumes with probable bibasilar atelectasis .