Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . There is superimposed mild pulmonary edema . There bibasilar opacities which are most likely atelectasis , left greater than right . Infection can not be entirely excluded . Cardiomediastinal silhouette is grossly unchanged .
    OUTPUT:
    
Mild pulmonary edema . Left basilar opacity . This could be due to a combination of atelectasis and / or infection .