title: Apparent diffusion coefficient in pancreatic cancer: characterization and histopathological correlations.
abstract: OBJECTIVE
  To clarify the components primarily responsible for diffusion abnormalities in pancreatic cancerous tissue.
  
  
  METHODS
  Subjects comprised 10 patients with surgically confirmed pancreatic cancer. Diffusion-weighted (DW) echo-planar imaging (b value = 0, 500 s/mm(2)) was employed to calculate the apparent diffusion coefficient (ADC). ADC values of cancer and noncancerous tissue were calculated. Furthermore, ADC values of the cancer were compared with histopathological results.
  
  
  RESULTS
  The mean (+/-standard deviation) ADC value was significantly lower for tumor (1.27 +/- 0.52 x 10(-3) mm(2)/s) than for noncancerous tissue (1.90 +/- 0.41 x 10(-3) mm(2)/s, P < 0.05). Histopathological examination showed similar proportions of fibrotic area, cellular component, necrosis, and mucin in each case. Regarding the density of fibrosis in cancer, three cases were classified in the loose fibrosis group and the remaining seven cases were classified in the dense fibrosis group. The mean ADC value was significantly higher in the loose fibrosis group (1.88 +/- 0.39 x 10(-3) mm(2)/s) than in the dense fibrosis group (1.01 +/- 0.29 x 10(-3) mm(2)/s, P < 0.05). In quantitative analysis, ADC correlated well with the proportion of collagenous fibers (r = -0.87, P < 0.05).
  
  
  CONCLUSIONS
  Collagenous fibers may be responsible for diffusion abnormalities in pancreatic cancer.
authors.affiliation: Department of Radiology, University of Fukui, Fukui, Japan. nmuraoka@u-fukui.ac.jp
authors.forename: Noriaki
authors.initials: N
authors.lastname: Muraoka
authors.forename: Hidemasa
authors.initials: H
authors.lastname: Uematsu
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Kimura
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Imamura
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Makoto
authors.initials: M
authors.lastname: Murakami
authors.forename: Akio
authors.initials: A
authors.lastname: Yamaguchi
authors.forename: Harumi
authors.initials: H
authors.lastname: Itoh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D005355:Fibrosis / Q000473:pathology; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D009077:Mucins; D009336:Necrosis / Q000473:pathology; D015588:Observer Variation; D010179:Pancreas / Q000473:pathology* / Q000648:ultrastructure*; D010190:Pancreatic Neoplasms / Q000175:diagnosis*; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media; D009077:Mucins