title: Computed tomography values calculation and volume histogram analysis for various computed tomographic patterns of diffuse lung diseases.
abstract: OBJECTIVE
  The aim of this study was to determine the computed tomography (CT) values of various pulmonary abnormalities in cubic region of interest (ROI) and square ROI and evaluate the CT findings by histogram analysis in the ROI.
  
  
  METHODS
  The study included 89 patients with the following 8 pulmonary CT patterns: normal lung, ground-glass attenuation, fine reticular opacity, coarse reticular opacity, honeycombing, airspace consolidation, nodular opacity, and emphysema. Cubic and square ROIs were selected in each CT pattern, and 5 values (contrast, variance, entropy, skewness, and kurtosis) were calculated.
  
  
  RESULTS
  In the histogram of ground-glass attenuation, fine reticular opacity, and coarse reticular opacity, peaks had moved to the right compared with the normal lung. Only emphysema had higher contrast and lower entropy than the normal lung (P < 0.001). The other abnormalities had lower contrast and higher entropy than the normal lung.
  
  
  CONCLUSIONS
  In conclusion, the shapes of histograms were characteristic of various abnormalities of the lung, and the values reflected the histogram quantitatively.
authors.affiliation: Department of Radiology, Osaka University Graduate School of Medical, 2-2 Yamadaoka, Suita, Osaka 565-0825, Japan. h-sumikawa@radiol.med.osaka-u.ac.jp
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Sumikawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Johkoh
authors.forename: Shuji
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yanagawa
authors.forename: Atsuo
authors.initials: A
authors.lastname: Inoue
authors.forename: Osamu
authors.initials: O
authors.lastname: Honda
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Yoshida
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Tomiyama
authors.forename: Hironobu
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015588:Observer Variation; D010363:Pattern Recognition, Automated; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult