Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Moderate - to - severe pulmonary edema has improved over the last 12 hours . A dual lumen left subclavian catheter tip is at upper right atrium . Increased retrocardiac density which is likely due to combination of atelectasis and pulmonary edema is minimally worsened . Top normal heart size , mediastinal and hilar contours are unchanged .
    OUTPUT:
    
Over the last 12 hours , moderate - to - severe pulmonary edema has improved .