Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Allowing for differences in technique and positioning , the cardiomediastinal silhouette is probably stable . Lungs are symmetrically expanded and mild pulmonary interstitial edema is unchanged . Slightly increased opacification at the left base may represent atelectasis . There is no large effusion or pneumothorax .
    OUTPUT:
    
Mild pulmonary interstitial edema , as before . Probable left basilar atelectasis , although early pneumonia can not be excluded . Clinical correlation is recommended .