Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is normal . The mediastinal and hilar contours are normal . No focal consolidation , pleural effusion or pneumothorax is present . Minimal streaky opacity in the retrocardiac region likely reflects atelectasis . There are no acute osseous abnormalities . Mild degenerative changes are seen within the thoracic spine .
    OUTPUT:
    
Minimal retrocardiac atelectasis .