Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac , mediastinal and hilar contours appear unchanged . Lung volumes are low . There is persistent perihilar fullness and interstitial abnormality suggesting pulmonary edema . There is a new focal opacity developing at the base of the right lung . There is no definite pleural effusion .
    OUTPUT:
    
Persistent findings suggesting pulmonary edema , probably similar allowing for differences in technique , but new developing focal right lower low lung opacity . Differential considerations include pneumonia or perhaps asymmetric pulmonary edema among other possible etiologies .