Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is stable marked hyperinflation of the lungs , increase in retrosternal space , increased AP diameter , and flattened hemidiaphragms . The lungs are clear . The hilar and cardiomediastinal contours are normal . There is no pneumothorax or pleural effusion . Pulmonary vascularity is normal .
    OUTPUT:
    
Stable severe emphysema with no evidence of pneumonia .