Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The masslike airspace opacity at the right hilum has improved slightly in appearance . Ring shadows in the right upper lobe are more prominent than on the prior study but similar in degree when compared to an earlier study from ___ . These likely reflect background changes of cystic fibrosis . There is improved aeration of the left lung with consequent improved visualization of airspace opacity at the left lung base . No pneumothorax seen .
    OUTPUT:
    
Slight interval improvement in the right perihilar airspace opacity , otherwise no significant interval change when compared to the prior study .