Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared with ___ , there has been interval improvement in left basilar atelectasis . An opacity at the right lung base remains , likely representing atelectasis , however pneumonia can not be excluded . There is a small right pleural effusion . No pneumothorax . Cardiomegaly is stable . Bilateral displaced rib fractures are again noted .
    OUTPUT:
    
1 . Persistent opacity at the right lung base likely represents atelectasis , however pneumonia can not be excluded . 2 . Interval improvement in left basilar atelectasis .