Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The appearance of the chest is strikingly similar the prior study . There are low inspiratory volumes , with bibasilar atelectasis . Minimal atelectasis at the right base is slightly more pronounced than on the remote prior study . The cardiomediastinal silhouette , with tortuous aorta , is unchanged , likely accentuated by low lung volumes . Slight prominence of the aortic knob appears stable ( measuring 5 .0 cm on today 's exam versus 4 .9 cm on the prior exam ) . No CHF , frank consolidation , or gross effusion is detected . Note is made of degenerative changes in the lumbar spine , with slight endplate scalloping of a lower thoracic and question L1 vertebral bodies .
    OUTPUT:
    
1 . Bibasilar atelectasis , but no convincing pneumonic infiltrate . The appearance is similar to ___ . 2 . Mild aneurysmal dilatation of the aortic knob is unchanged compared with ___ . The cardiomediastinal silhouette is similar to the prior study .