Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Since the prior exam , the lung volumes are lower . There is new mild - to - moderate interstitial edema . The more focal opacity at the left base likely represents atelectasis . There is no pleural effusion or pneumothorax . The mediastinal contours are widened , though unchanged from the prior exam . The heart size is mildly enlarged . Sternal wires are intact .
    OUTPUT:
    
New mild to moderate pulmonary edema with probable retrocardiac atelectasis .