Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is top normal . Mediastinal and hilar contours are unremarkable . There is no pulmonary edema . Minimal patchy opacity in the retrocardiac region likely reflects atelectasis . No pleural effusion or pneumothorax is demonstrated . There are no acute osseous abnormalities .
    OUTPUT:
    
Minimal atelectasis in the retrocardiac region .