Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy again with a top normal - sized cardiac silhouette and mildly tortuous thoracic aorta . Hilar contours are unremarkable . Lung volumes are low with right base atelectasis as well as increased focal retrocardiac opacity with lateral posterior lower lobe correlate . Right - sided Port - A - Cath is again demonstrated terminating at the cavoatrial junction . There is no pleural effusion or pneumothorax . There is no overt pulmonary edema . Calcified mediastinal lymph nodes are again noted .
    OUTPUT:
    
Low lung volumes with a focal retrocardiac opacity with lower lobe correlate on lateral view . This may represent either atelectasis or infection , and correlation with clinical presentation is recommended .