Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared with the supine trauma board film obtained earlier the same day , the current film is also obtained supine , with slightly better , but still low , inspiratory volumes . As before , the mediastinum appears prominent and there is probable mild cardiomegaly . There is upper zone redistribution , without overt CHF . There is bibasilar atelectasis , slightly improved at the left base . No effusion . No apical capping is suggested . No pneumothorax is detected .
    OUTPUT:
    
Continued concern for possible mediastinal enlargement . However , the appearance is improved compared with earlier the same day . This would be best further assessed with upright PA and lateral CXR views , when the patient is able to tolerate it . Alternatively , chest CT could help for further assessment .