Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A portable frontal chest radiograph demonstrates unchanged cardiac size . Increased diffuse bilateral opacity suggests mild pulmonary edema superimposed on known underlying interstitial lung disease . No definite focal consolidation is identified , although difficult to evaluate given overlying opacity . No pneumothorax is appreciated . Surgical clips project over the left axilla .
    OUTPUT:
    
Mild pulmonary edema superimposed on known underlying interstitial lung disease . No definite focal consolidation identified , though difficult to evaluate given overlying opacity .