Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi-erect chest radiograph ___ at 13 :59 is submitted .
    OUTPUT:
    
Interval improvement but residual mild pulmonary and interstitial edema . Patchy bibasilar opacities likely reflect atelectasis in the setting of low volumes . Overall cardiac and mediastinal contours are stable . No pneumothorax .