Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to the prior study , there has been interval clearing of the opacity at the right lung base , with only minimal residual subsegmental atelectasis there . Otherwise , I doubt significant interval change . No overt CHF . No new focal infiltrate . Extreme right costophrenic angles excluded from the film the presence of a small right pleural effusion can not be excluded . The left costophrenic sulcus is clear .
    OUTPUT:
    
Interval clearing of right base opacity . No new focal infiltrate identified . Small residual right pleural effusion can not be excluded .