title: Computed tomography correlates with pulmonary exacerbations in children with cystic fibrosis.
abstract: BACKGROUND
  High-resolution computed tomography (HRCT) has been suggested as a potential outcome surrogate for cystic fibrosis (CF) lung disease. An important attribute of a valid outcome surrogate is that the surrogate reflects true clinical outcomes.
  
  
  OBJECTIVE
  We performed this study to validate HRCT, a proposed surrogate outcome measure for CF lung disease, against a true clinical outcome, the number of respiratory tract exacerbations occurring in 2 yr, and to assess the correlation of CT scores and pulmonary function tests (PFTs) with this clinical outcome.
  
  
  METHODS
  CTs and PFTs were performed on 6- to 10-yr-old children at the beginning and end of a 2-yr study during which the number of exacerbations were recorded. Spearman correlations and Poisson models were used to assess the correlation of the number of exacerbations with baseline values and changes in PFTs and CT scores.
  
  
  RESULTS
  Nine of 61 subjects had a total of 22 respiratory tract exacerbations. At baseline, PFTs and four CT scores showed significant correlation with number of exacerbations, but no variable by itself predicted exacerbations with high accuracy. For change over the 2-yr period, three CT scores showed significant correlation with exacerbations, whereas no PFTs showed significant correlation.
  
  
  CONCLUSIONS
  This is the first study showing correlation between CT and a true clinical outcome. Change in CT scores correlates moderately well with the number of exacerbation. Poor correlation between change in FEV1 and exacerbations suggests that HRCT may be a more appropriate outcome surrogate for longitudinal studies of young children.
authors.affiliation: Department of Radiology, MLC-5031, Cincinnati Children's Hospital, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA. alan.brody@cchmc.org
authors.forename: Alan S
authors.initials: AS
authors.lastname: Brody
authors.forename: Heidi
authors.initials: H
authors.lastname: Sucharew
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Campbell
authors.forename: Steven P
authors.initials: SP
authors.lastname: Millard
authors.forename: Paul L
authors.initials: PL
authors.lastname: Molina
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Klein
authors.forename: Joanne
authors.initials: J
authors.lastname: Quan
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D002648:Child; D003550:Cystic Fibrosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000188:drug therapy; D003850:Deoxyribonuclease I / Q000627:therapeutic use; D005260:Female; D006760:Hospitalization; D006801:Humans; D007262:Infusions, Intravenous; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D015203:Reproducibility of Results; D012120:Respiration Disorders / Q000209:etiology*; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; C085693:DNASE1 protein, human; D003850:Deoxyribonuclease I