title: Repeatability of lung density measurements with low-dose computed tomography in subjects with alpha-1-antitrypsin deficiency-associated emphysema.
abstract: OBJECTIVE
  Multislice computed tomography (MSCT) of the lungs provides a new opportunity for longitudinal assessment of lung densities because of shorter scan duration. The aim of the present study was to assess the intraindividual variation of lung densities measured by MSCT of patients with emphysema.
  
  
  METHODS
  Ten patients with emphysema participated in a study in which MSCT was obtained on two occasions, approximately 2 weeks apart. Scanning parameters were 140 kV, 20 mAs, 4 x 2.5-mm collimation, and effective slice thickness of 2.5 mm. Lung density was measured as the 15th percentile point and the relative area below -910 Hounsfield units (HU) by using Pulmo-LKEB software.
  
  
  RESULTS
  The mean difference of the 15th percentile point was -1.29 +/- 3.2 HU, and that for the relative area below the -910-HU parameter was -1.02% +/- 3.09%. Intraclass coefficients of variation were 0.96 (0.86-0.99) and 0.94 (0.8-0.98), respectively (95% confidence interval).
  
  
  CONCLUSIONS
  Lung density parameters of emphysema derived by MSCT provide an opportunity for analysis of the treatment effects of new drugs on the progression of emphysema.
authors.affiliation: Department of Pulmonology (C3-P), Leiden University Medical Center, Leiden, the Netherlands. j.stolk.long@lumc.nl
authors.forename: J
authors.initials: J
authors.lastname: Stolk
authors.forename: A
authors.initials: A
authors.lastname: Dirksen
authors.forename: A A
authors.initials: AA
authors.lastname: van der Lugt
authors.forename: J
authors.initials: J
authors.lastname: Hutsebaut
authors.forename: J
authors.initials: J
authors.lastname: Mathieu
authors.forename: J
authors.initials: J
authors.lastname: de Ree
authors.forename: J H
authors.initials: JH
authors.lastname: Reiber
authors.forename: B C
authors.initials: BC
authors.lastname: Stoel
mesh_terms: D018450:Disease Progression; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D011829:Radiation Dosage; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods; D019896:alpha 1-Antitrypsin Deficiency / Q000150:complications*