Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded with equivocal mild pulmonary edema . Retrocardiac opacity is somewhat increased from the prior study and could reflect atelectasis , though infection can not be excluded . There is no pleural effusion or pneumothorax . Marked cardiomegaly is slightly progressed from the previous examination . Single lead ICD is unchanged . Left neck clips could reflect prior carotid intervention .
    OUTPUT:
    
Equivocal mild pulmonary edema . Retrocardiac opacity , most likely atelectasis but could reflect infection in the appropriate clinical circumstance .