Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is persistent hyperinflation of the lungs and bullous emphysema of the upper lung fields , with flattened hemidiaphragms consistent with severe COPD . Scarring at the left lower lobe is unchanged . No evidence of focal lung consolidation . No pleural effusion or pneumothorax . The cardiomediastinal silhouette is unremarkable .
    OUTPUT:
    
Severe bullous emphysema has not changed since the prior study . No new focal consolidation concerning for pneumonia .