Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lung volumes are low . A retrocardiac opacity is present , and likely atelectasis . No other focal airspace opacities are identified . There vascular engorgement and mild pulmonary edema . There are small bilateral pleural effusions . There is no pneumothorax . The mediastinal contours are normal . The heart is mildly enlarged .
    OUTPUT:
    
1 . Mild pulmonary edema and small bilateral pleural effusions . 2 . Mild cardiomegaly . 3 . Retrocardiac opacity , which is likely atelectasis . Pneumonia can not be completely excluded .