Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal views of the chest . Moderate cardiomegaly is similar to prior . There is mild interstitial pulmonary edema and improved small retrocardiac opacification . No substantial pleural effusion or pneumothorax .
    OUTPUT:
    
Mild pulmonary edema . Retrocardiac opacification has improved , but could represent atelectasis or infection in the appropriate clinical setting .