Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single portable AP upright view of the chest was obtained . In comparison to the prior study , the cardiac silhouette has slightly increased in size and the pulmonary vasculature is less distinct with cephalization of the vessels , consistent with mild pulmonary edema . Previously noted interstitial changes at the bases are less prominent as a result of superimposed edema . No large effusion or pneumothorax .
    OUTPUT:
    
Interval development of mild pulmonary edema on a background of chronic interstitial lung disease .