Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable supine AP view of the chest . Biapical scarring is again seen . There is no visualized pneumothorax . Cardiomediastinal silhouette is within normal limits . No displaced rib fractures identified . Known left rib fracture is not identified .
    OUTPUT:
    
No definite acute cardiopulmonary process . Known left rib fracture not clearly seen on this exam .