Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single frontal chest radiograph demonstrates severe emphysema , characterized by pulmonary hyperexpansion , reticular basilar opacities , and lucency indicating bullae at the apices . There is increased opacity in the left lung base concerning for pneumonia . The cardiac silhouette is mildly enlarged , the mediastinal contours are notable only for tortuosity of the aorta .
    OUTPUT:
    
Severe bullous emphysema with accompanying interstitial abnormality upon which is concerning for superimposed left basilar pneumonia .