Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest were obtained . There is hyperinflation of the lungs with upper lobe lucency , compatible with underlying emphysema . There are mild Kerley B lines suggesting mild CHF . Chronic opacity at the left lung base is most compatible with scarring , though pneumonia can not be entirely excluded . The heart size is top normal . The mediastinal contour is stable with atherosclerotic calcification along the aortic knob . The bony structures appear intact .
    OUTPUT:
    
Top normal heart size with mild interstitial edema . Stable opacity at the left lung base , likely chronic area of scarring given stability over time .