Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post esophagectomy with gastric pull - through . High density material at the right lung base from prior barium aspiration is again seen . There is subtle retrocardiac opacity which may have correlate over the spine on the lateral view . The lungs are hyperinflated but otherwise clear . Cardiomediastinal silhouette is otherwise unremarkable . Chronic changes of the right ribs are again noted .
    OUTPUT:
    
Retrocardiac opacity is potentially atelectasis though infection or aspiration would be possible .