Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are low in volume but show bilateral interstitial and focal airspace opacities . The cardiac silhouette is enlarged . The ediastinal silhouette and hilar contours are normal . No pleural effusions or pneumothorax is present . The patient has a midline sternotomy .
    OUTPUT:
    
Mild - to - moderate pulmonary edema .