Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Diffuse bilateral predominantly perihilar patchy airspace opacities . Trace bilateral pleural effusions . No pneumothorax identified . The size of the cardiac silhouette is enlarged but unchanged .
    OUTPUT:
    
Diffuse bilateral , predominantly perihilar patchy airspace opacities consistent with pulmonary edema . Superimposed infection however can not be excluded .