Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright study dated ___ at 18 56 is submitted .
    OUTPUT:
    
There is slight worsening of mild interstitial edema . Persistent patchy opacity at both bases may reflect atelectasis in the setting of small effusions , although superimposed infectious process can not be excluded . No pneumothorax . Overall cardiac and mediastinal contours are stable .