title: Radiodensity on serial chest X-rays for the diagnosis of foreign body aspiration in children.
abstract: OBJECTIVE
  To evaluate the utility of measuring lung radiodensity from chest X-ray for the diagnosis of foreign body aspiration.
  
  
  METHODS
  Records of 59 children with foreign body aspiration were retrospectively reviewed. Lung radiodensity and radiodensity ratio (right/left lung radio density) before and after foreign body removal were measured. Radiodensity was calculated as the relative score compared with the tenth thoracic vertebra body (100 points) and the background (0 point). The change of radiodensity ratio (difference in radiodensity ratio of the second X-ray from that of first X-ray) was compared between 22 patients (foreign body group) and 22 normal subjects (control group).
  
  
  RESULTS
  In the group of foreign body in the left bronchus, the mean (SD) radiodensity of the left lung [53.5 (12.8)] was lower than that of the right lung [60.8 (7.7), P<0.01] and it increased after foreign body removal [60.0 (6.9), P=0.02]. The radiodensity ratio decreased from 1.20 (0.30) to 0.96 (0.09) (P<0.01) after foreign body removal. In the group with a foreign body in the right bronchus, the radiodensity of the right lung [51.8 (12.8)] was lower than that of left lung [62.0 (11.7), P=0.03], and it also increased after foreign body removal [58.4 (9.6), P=0.03]. The change of radiodensity ratio in the foreign body group [15.7 (17.8)%] was higher than the control group [5.4 (4.3) %, P=0.01] and the cutoff value was 7.5%.
  
  
  CONCLUSIONS
  Radiodensity from chest X-ray could be a useful tool for diagnosing foreign body aspiration in children.
authors.affiliation: Departments of Pediatrics and Thoracic and Cardiovascular Surgery, Chonnam National University Hospital, Chonnam National University Medical School;Departments of Pediatrics, Chonnam National University Hwasun Hospital, Chonnam National University Medical School and The Heart Center of Chonnam National University Hospital, the Research Institute of Medical Sciences of Chonnam National University, Gwangju, South Korea. Correspondence to: Young Kuk Cho, Department of Pediatrics, Chonnam National University Medical School, 42 Jebong ro, Dong gu, Gwangju 501 757, South Korea.ESS and DKH contributed equally to the paper. youngcx@hanmail.net.
authors.forename: Eun Song
authors.initials: ES
authors.lastname: Song
authors.forename: Dong Kyun
authors.initials: DK
authors.lastname: Han
authors.forename: Hwa Jin
authors.initials: HJ
authors.lastname: Cho
authors.forename: In Seok
authors.initials: IS
authors.lastname: Jeong
authors.forename: Namsik
authors.initials: N
authors.lastname: Yoon
authors.forename: Jae Sook
authors.initials: JS
authors.lastname: Ma
authors.forename: Young Kuk
authors.initials: YK
authors.lastname: Cho
mesh_terms: D002675:Child, Preschool; D005260:Female; D005547:Foreign Bodies / Q000000981:diagnostic imaging*; D006801:Humans; D007223:Infant; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D013902:Radiography, Thoracic / Q000379:methods*; D053120:Respiratory Aspiration / Q000000981:diagnostic imaging*; D012189:Retrospective Studies