title: High resolution CT in cystic fibrosis--the contribution of expiratory scans.
abstract: BACKGROUND
  The use of high-resolution computed tomography (HRCT) is well accepted as an accurate method for evaluation of lung parenchyma in cystic fibrosis (CF). Several scoring methods exist and, in common, all are based on HRCT findings during inspiration alone.
  
  
  OBJECTIVE
  To examine whether expiratory HRCT scans could add information about the degree of mosaic perfusion in patients with CF.
  
  
  METHODS
  Pulmonary HRCT was performed in 17 CF patients (median age of 12 years) with 1-mm thin sections and 10-mm intervals during inspiration, followed by 1-mm thin sections with 20-mm intervals during expiration. HRCT was scored by using a modified Bhalla method.
  
  
  RESULTS
  The mean HRCT score was 8.2. Out of 17 patients, 11 (65%) demonstrated a pathological mosaic perfusion in expiration, while only three patients showed mosaic perfusion in inspiration. The degree of expiratory mosaic perfusion was graded as severe in nine patients and moderate in two patients. There was a significant correlation between our modified HRCT score and lung function, as measured by forced expiratory volume in 1 s (FEV1% predicted, P<0.01).
  
  
  CONCLUSIONS
  Mosaic perfusion in expiration was a common pathological HRCT finding in our study group. The clinical significance of this finding needs further evaluation.
authors.affiliation: Department of Paediatrics, Children's Hospital, Haukeland University Hospital, 5021 Bergen, Norway. ludger.dorloechter@haukeland.no
authors.forename: Ludger
authors.initials: L
authors.lastname: Dorlöchter
authors.forename: Harald
authors.initials: H
authors.lastname: Nes
authors.forename: Gjermund
authors.initials: G
authors.lastname: Fluge
authors.forename: Karen
authors.initials: K
authors.lastname: Rosendahl
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D014057:Tomography, X-Ray Computed / Q000379:methods*