Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: In comparison to chest radiographs dated ___ , no significant changes are identified . Allowing for differences in patient rotation , the the previously identified left upper lobe opacity is stable in size and appearance . A focal , linear opacity in the left lower lobe likely reflects scarring or atelectasis . There is also stable scarring , atelectasis , or a small pleural effusion at the right costophrenic angle . There are calcifications within the wall of the aortic arch . Bilateral hyper inflation is unchanged . There is severe osteopenia and unchanged compression deformities of T11 - T12 .
    OUTPUT:
    
Unchanged appearance of left upper lobe mass . No evidence of pneumonia .