title: Lung structure-function correlation in patients with primary ciliary dyskinesia.
abstract: BACKGROUND
  Primary ciliary dyskinesia (PCD) is a rare disease, characterised by chronic airway infection. In cystic fibrosis, FEV1 is insensitive to detect patients with structural damage, and Lung Clearance Index (LCI) was proposed as a better marker of early lung damage. In PCD, the relationship between functional and structural abnormalities has been less studied. We aimed to re-examine this in a cohort of children and adults with mild to moderate PCD.
  
  
  METHODS
  Thirty-eight patients with PCD (5.2-25.0 years) and 70 healthy controls (4.4-25.8 years) were recruited to compare LCI, measured by N2 multiple breath washout and FEV1 in a prospective observational trial. In a subset of 30 patients who underwent chest imaging, structural abnormalities were evaluated with cystic fibrosis computed tomography (CFCT) scores.
  
  
  RESULTS
  LCI was abnormal in 28 of 38 patients and a moderate correlation was observed between LCI and FEV1 (r=-0.519, p=0.001). Moreover, LCI correlated well with CFCT total score (r=0.800, p<0.001) and also with subscores for airway wall thickening (r=0.809, p<0.001), mucus plugging (r=0.720, p<0.001) and bronchiectasis (r=0.494, p<0.001). Concordance was seen between LCI and CFCT in 25 of 30 (83%) patients, but between FEV1 and CFCT in only 16 of 30 (53%) patients. LCI was more sensitive (90.9%, 95% CI 70.8 to 98.6) to detect patients with structural abnormalities than FEV1 (36.4%, 95% CI 17.2 to 59.3).
  
  
  CONCLUSIONS
  We demonstrated that measuring LCI in patients with PCD is of clinical relevance; it was more frequently abnormal than FEV1, correlated well with CFCT and was more sensitive than FEV1 to detect patients with structural abnormalities.
authors: Department of Pediatrics, Pediatric Pulmonology, University Hospital Gasthuisberg, Leuven, Belgium.
authors: Mieke
authors: M
authors: Boon
authors: Department of Pediatrics, Pediatric Pulmonology, University Hospital Gasthuisberg, Leuven, Belgium.
authors: Francois L
authors: FL
authors: Vermeulen
authors: Department of Pediatrics, Pediatric Pulmonology, University Hospital Gasthuisberg, Leuven, Belgium.
authors: Willem
authors: W
authors: Gysemans
authors: Department of Pediatrics, Pediatric Pulmonology, University Hospital Gasthuisberg, Leuven, Belgium.
authors: Marijke
authors: M
authors: Proesmans
authors: Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Gasthuisberg Leuven, Leuven, Belgium.
authors: Mark
authors: M
authors: Jorissen
authors: Department of Pediatrics, Pediatric Pulmonology, University Hospital Gasthuisberg, Leuven, Belgium.
authors: Kris
authors: K
authors: De Boeck
mesh_terms: D000293:Adolescent; D000328:Adult; D001944:Breath Tests / Q000379:methods; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002925:Ciliary Motility Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D009079:Mucociliary Clearance / Q000502:physiology; D011446:Prospective Studies; D013147:Spirometry / Q000379:methods; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Bronchiectasis; Imaging/CT MRI etc; Rare lung diseases