title: Age-related normal ranges for the Haller index in children.
abstract: OBJECTIVE
  The Haller index is an accepted CT method for evaluating thoracic dimensions in patients with pectus excavatum. The purpose of this study is to establish age- and gender-related norms for the Haller index in childhood.
  
  
  METHODS
  We retrospectively reviewed 574 consecutive chest CT examinations (M=285, F=289) performed at our institution from August 2001 through March 2002. Seventeen patients with a history of chest-wall deformity, trauma, or syndrome were excluded, for a total sample size of 557 patients. The Haller index was calculated for each patient, using electronic calipers. The sample population was then separated by gender and placed into 2-year age groupings. Two-way analysis of variance and Tukey's multiple comparisons were performed to determine significance at a=0.05. The least-square mean Haller index values for each age group and gender were calculated with 95% confidence intervals.
  
  
  RESULTS
  In both males and females, the 0- to 2-year age group showed a significantly smaller mean Haller index than older children. In addition, females had significantly greater Haller index values than males in the 0- to 6- and 12- to 18-year age groups.
  
  
  CONCLUSIONS
  The Haller index, a quantitative measurement of chest-wall configuration, demonstrates significant age- and gender-related variability. This should be considered when evaluating the patient with suspected chest-wall deformity.
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Daunt
authors.forename: Justine H
authors.initials: JH
authors.lastname: Cohen
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Miller
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D003955:Diagnostic Tests, Routine; D005260:Female; D005660:Funnel Chest / Q000000981:diagnostic imaging* / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D013902:Radiography, Thoracic; D012016:Reference Values; D012189:Retrospective Studies; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D035441:Thoracic Wall / Q000033:anatomy & histology*; D014057:Tomography, X-Ray Computed / Q000379:methods*