Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear opacity at the right lung base is most compatible with scarring . There is a left basilar opacity partially silhouetting the hemidiaphragm . Some of this may also be due to atelectasis and scarring although underlying effusion would be possible as well . Superiorly , lungs are clear . The cardiomediastinal silhouette is within normal limits . Old healed right posterior rib fractures are noted . Left upper quadrant coils are again noted .
    OUTPUT:
    
Left basilar opacity likely in part due to atelectasis though superimposed effusion is also possible .