title: Quantitative Emphysema Distribution in Anatomic and Non-anatomic Lung Regions.
abstract: OBJECTIVE
  The change of emphysema distribution with increasing COPD severity is not yet assessed. Especially, involvement of the upper aspect of the lower lobe is unknown. The primary aim was to quantitatively determine regional distribution of emphysema in anatomically (lung lobes) and non-anatomically defined lung regions (upper/lower lung halves as well as core and rind regions) in a cohort covering equally all COPD severity stages using CT.
  
  
  METHODS
  Basically 100 CT data sets were quantitatively evaluated for regional distribution of emphysema. Emphysema characteristics (emphysema index, mean lung density and 15th percentile of the attenuation values of lung voxels) were compared (t-test) in: upper lobes vs. upper halves, lower lobes vs. lower halves, core vs. rind region.
  
  
  RESULTS
  In patients with ≤ GOLD II, a significantly higher emphysema burden was found in the upper lobes as compared to upper halves. In subjects with GOLD III/IV the differences were not significant for all emphysema characteristics. A high difference between lobes and halves in subjects with ≤ GOLD II was found, in contrast to low difference in higher GOLD stages.
  
  
  CONCLUSIONS
  Lobar segmentation provides improved characterization of cranio-caudal emphysema distribution compared to a non-anatomic approach in subjects up to GOLD stage II.
authors.affiliation: 1Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg , Heidelberg , Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Owsijewitsch
authors.forename: Julia
authors.initials: J
authors.lastname: Ley-Zaporozhan
authors.forename: Jan-Martin
authors.initials: JM
authors.lastname: Kuhnigk
authors.forename: Annette
authors.initials: A
authors.lastname: Kopp-Schneider
authors.forename: Ralf
authors.initials: R
authors.lastname: Eberhardt
authors.forename: Monika
authors.initials: M
authors.lastname: Eichinger
authors.forename: Claus Peter
authors.initials: CP
authors.lastname: Heussel
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Kauczor
authors.forename: Sebastian
authors.initials: S
authors.lastname: Ley
mesh_terms: D015331:Cohort Studies; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging*; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging*; D012720:Severity of Illness Index
keywords: CT; emphysema quantitation; regional distribution