Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is mild interstitial edema , and the heart is normal in size . A left basilar opacity may reflect atelectasis versus pneumonia . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Mild interstitial edema . Left basilar opacity may reflect atelectasis though infection can be considered in the appropriate clinical setting .