Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy . Heart size is mildly enlarged but similar . Lung volumes are low with patchy opacities in the lung bases likely reflective of atelectasis . No focal consolidation , large pleural effusion or pneumothorax is present . Crowding of bronchovascular structures is present .
    OUTPUT:
    
Low lung volumes with bibasilar atelectasis .