Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable supine AP view of the chest was provided . There is massive widening of the mediastinum for which CT is strongly advised to further assess . The lungs are clear aside from mild bibasilar atelectasis . The heart size appears within normal limits . Bony structures are intact .
    OUTPUT:
    
Significantly widened mediastinum for which CT is recommended to further evaluate .