Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Kerley B lines and interstitial opacities indicate progressive pulmonary edema since Septmember . Thick linear opacities at the left lower lobe may be secondary to aspiration . Review of prior radiographs demonstrates an underlying pattern of COPD . The heart and mediastinal contour are normal .
    OUTPUT:
    
1 . Mild interstitial edema . 2 . Possible aspiration , left lower lobe .