title: Air trapping in heart-lung transplant recipients: variability of anatomic distribution and extent at sequential expiratory thin-section CT.
abstract: OBJECTIVE
  To evaluate the intrapatient reproducibility of the extent and anatomic distribution of air trapping at sequential expiratory thin-section computed tomographic (CT) examinations in heart-lung transplant recipients.
  
  
  METHODS
  Nineteen heart-lung transplant recipients (eight with and 11 without bronchiolitis obliterans syndrome [BOS]) underwent three expiratory CT examinations within 1 hour. Residual volumes were measured at CT. Anatomic distribution and extent of air trapping were scored by two observers at two independent readings, and the reproducibility of observations was calculated for each feature. CT examination results were compared by using an analysis of variance that took into account interobserver and BOS and non-BOS effects. The Spearman rank correlation coefficient was calculated to test the association between variability of residual volumes and variability of the extent of air trapping.
  
  
  RESULTS
  Residual volumes did not significantly differ between the three CT examinations (P =.556). Reproducibility values for findings of anatomic distribution of air trapping ranged from 84% to 95%, with a tendency toward improved reproducibility in patients without BOS. Mean reproducibility values for the extent of air trapping ranged from 97.1% to 97.7%, and no substantial difference in these values between patients with and those without BOS was observed. The Spearman rank coefficient for the correlation between variability of residual volumes and variability of extent of air trapping ranged from 0.382 to 0.568 (P =.105-.016). No interobserver effect was detected (P =.944).
  
  
  CONCLUSIONS
  Anatomic distribution and extent are reproducible characteristics of air trapping. No substantial variability of air trapping occurs in functionally stable heart-lung transplant recipients.
authors.affiliation: Department of Radiology, University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria. alexander.bankier@univie.ac.at
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Bankier
authors.forename: Alain
authors.initials: A
authors.lastname: Van Muylem
authors.forename: Pietro
authors.initials: P
authors.lastname: Scillia
authors.forename: Viviane
authors.initials: V
authors.lastname: De Maertelaer
authors.forename: Marc
authors.initials: M
authors.lastname: Estenne
authors.forename: Pierre Alain
authors.initials: PA
authors.lastname: Gevenois
mesh_terms: D000328:Adult; D000388:Air; D001989:Bronchiolitis Obliterans / Q000150:complications; D045853:Exhalation / Q000502:physiology; D005260:Female; D016041:Heart-Lung Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed / Q000379:methods*