Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single portable frontal chest radiograph was obtained . An endotracheal tube terminates appropriately above the carina . The side hole and tip of the enteric catheter are below the diaphragm . The lungs are well expanded . A triangular opacity at the right hilus / perihilar region does not obscure the right heart border . There is left base atelectasis . There is no pneumothorax or effusion . Cardiac and mediastinal contours are normal .
    OUTPUT:
    
Right hilar / perihilar opacity may reflect combination of right lower lobe atelectasis and aspiration , although infection or contusion not excluded in appropriate clinical setting .