Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . Lungs are clear with upper lobe lucency compatible with known emphysema . There is no focal consolidation , effusion , or pneumothorax . The cardiomediastinal silhouette is stable with borderline cardiomegaly . Imaged osseous structures are intact . No displaced rib fractures . No free air below the right hemidiaphragm is seen .
    OUTPUT:
    
Emphysema without superimposed acute process .