Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Mild cardiomegaly and prominent mediastinum are unchanged since at least ___ . Hilar contours are unremarkable . There is mild interstitial edema . Linear densities in bilateral mid - to - lower lung fields likely represent atelectasis . Pleural surfaces are clear without effusion or pneumothorax .
    OUTPUT:
    
Mild pulmonary edema . No pneumonia .