Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and aortic valve replacement . There are low lung volumes . The cardiac , mediastinal and hilar contours are unchanged , with the heart size appearing normal . The aorta remains tortuous and demonstrates atherosclerotic mural calcifications . Elevation of the right hemidiaphragm is chronic . Crowding of the bronchovascular structures is noted , but no overt pulmonary edema is present . Streaky linear opacities in both lung bases are demonstrated , and could reflect atelectasis or scarring . No new focal consolidation , pleural effusion or pneumothorax is demonstrated . Degenerative changes of both acromioclavicular joints and right glenohumeral joint are again seen .
    OUTPUT:
    
Bibasilar atelectasis or scarring with chronic elevation of the right hemidiaphragm . No acute cardiopulmonary abnormality otherwise noted .