Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are hyperexpanded but clear of focal opacities . Left base scaring is present , unchanged . Cardiomediastinal silhouette , hilar contours and pleural surfaces are normal . No pleural effusion or pneumothorax is present . Old right - sided and left - sided rib fractures are again seen .
    OUTPUT:
    
No evidence of acute intrathoracic process . Hyperexpanded airways consistent with chronic obstructive pulmonary disease .