title: Detection of air trapping on inspiratory and expiratory phase images obtained by 0.3-second cine CT in the lungs of free-breathing young children.
abstract: OBJECTIVE
  The objective of our study was to evaluate whether 0.3-second cine CT can be used to detect air trapping in the lungs of young children.
  
  
  METHODS
  In 30 children (mean age, 25 months), 0.3-second cine CT was performed at six levels during 3 seconds of quiet breathing. The study population was divided into an air trapping group (n = 24) and a no-air trapping group (n = 6). Lung density was measured at an abnormal area (with or without air trapping) and an adjacent normal area on inspiratory and expiratory phase images. Lung density differences between inspiration and expiration were calculated and compared in abnormal areas (with or without air trapping) and in normal areas. Their percentages were calculated and compared between the two groups. In addition, lung density differences between abnormal and adjacent normal areas were calculated and compared between the two groups.
  
  
  RESULTS
  Lung density differences between inspiration and expiration were smaller in areas with air trapping (mean +/- SD, -19 +/- 34 H) than in abnormal areas without air trapping (138 +/- 36 H) (p < 0.001) or in normal areas (111 +/- 49 H) (p < 0.001). Their percentages were smaller in the group with air trapping (-27% +/- 54%) than in the group with no air trapping (120% +/- 87%) (p < 0.001). In the group with air trapping, lung density differences were larger at the expiratory phase (260 +/- 77 H) than at the inspiratory phase (129 +/- 69 H) (p < 0.001), but did not change through the respiratory cycle in the group with no air trapping (p > 0.05).
  
  
  CONCLUSIONS
  Air trapping can be accurately detected in the lungs of free-breathing young children using 0.3-second cine CT.
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap-2 dong, Songpa-gu, Seoul 138-736, South Korea. hwgoo@amc.seoul.kr
authors.forename: Hyun Woo
authors.initials: HW
authors.lastname: Goo
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Kim
mesh_terms: D001980:Bronchi / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D045853:Exhalation; D005260:Female; D006801:Humans; D007223:Infant; D001239:Inhalation; D008168:Lung / Q000000981:diagnostic imaging*; D008171:Lung Diseases / Q000000981:diagnostic imaging; D019568:Lung, Hyperlucent / Q000000981:diagnostic imaging; D008297:Male; D014057:Tomography, X-Ray Computed