Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral chest views were obtained with patient in upright position . Analysis is performed in direct comparison with the next preceding similar study of ___ . Heart size remains normal . No configurational abnormality is noted . Unchanged appearance of thoracic aorta without evidence of local contour abnormalities . Pulmonary vasculature is not congested . Again seen are bilateral extensive fibrotic changes in the upper lung zones coinciding with elevation of the hilar structures . These changes have not undergone any alteration during the latest three - year examination interval . Comparison is extended to an older chest examination of ___ and again there is no evidence of any interval change .
    OUTPUT:
    
Stable upper lobe changes of mostly interstitial nature including hilar elevation compatible with the clinical diagnosis of sarcoidosis . The present examination excludes new acute pulmonary abnormalities .