Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours are normal . Again seen is severe bilateral emphysema , predominant in the lower lobes , consistent with alpha - 1 - antitrypsin deficiency . Enlargement of pulmonary arteries suggests pulmonary arterial hypertension . Linear areas of focal lung scarring are unchanged . No new consolidation , pulmonary edema , pleural effusion or pneumothorax is seen .
    OUTPUT:
    
Extensive bibasilar predominant emphysema , in keeping with alpha 1 antitrypsin deficiency . Enlarged pulmonary arteries suggestive of pulmonary arterial hypertension , unchanged .