title: [Does HRCT-emphysema index represent the entire lung?].
abstract: OBJECTIVE
  : Comparison of emphysema index derived of thin section MD-CT of the entire lung volume and HRCT, simulated by calculation of every twentieth image of the whole data-set.
  
  
  METHODS
  Pulmonary emphysema was quantified by semiautomatic, segmentation of lung borders and assessment of lung volume and emphysema volume within these borders. The emphysema index (pixel index) was calculated. Statistical analysis was done by the sign-test and Bland-Altman-analysis.
  
  
  RESULTS
  Median lung volume, emphysema volume and emphysema index are significantly higher in simulated HRCT. Median lung volume (emphysema volume) calculated by HRCT is 5118 ml (407 ml) and 5040 ml (367 ml) calculated by the entire MD-CT data-set, representing differences of 1 and 8 % related to the median lung and emphysema volumes. Emphysema index is 0.09 (HRCT) and 0.08 (MD-CT).
  
  
  CONCLUSIONS
  HRCT overrates emphysema index compared to thin section MD-CT of the entire lung volume.
authors.affiliation: Klinik und Poliklinik für Radiologie, Johannes Gutenberg-Universität, Mainz. achenbac@uni-mainz.de
authors.forename: T
authors.initials: T
authors.lastname: Achenbach
authors.forename: C
authors.initials: C
authors.lastname: Buschsieweke
authors.forename: A
authors.initials: A
authors.lastname: Gerhards
authors.forename: K
authors.initials: K
authors.lastname: Gast
authors.forename: C P
authors.initials: CP
authors.lastname: Heussel
authors.forename: M
authors.initials: M
authors.lastname: Thelen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D019412:Anatomy, Cross-Sectional / Q000379:methods*; D004646:Emphysema / Q000145:classification* / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D016247:Information Storage and Retrieval / Q000379:methods; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*