title: Diffusion-weighted imaging of the healthy pancreas: apparent diffusion coefficient values of the normal head, body, and tail calculated from different sets of b-values.
abstract: OBJECTIVE
  To evaluate differences in apparent diffusion coefficient (ADC) values between head, body, and tail regions and the impact of sets of b-values used in diffusion weighted imaging (DWI) of the normal pancreas.
  
  
  METHODS
  In 51 healthy volunteers echo-planar DWI of the pancreas was prospectively performed with b-values of 50, 400, and 800 s/mm(2) . All four possible combinations of b-values were used to calculate ADC values in a total of 587 regions in the pancreas head, body, and tail regions. Dependency of ADC values on the anatomical regions and on the applied sets of b-values was calculated using multivariate analysis of variance (ANOVA).
  
  
  RESULTS
  Mean ADC values differed significantly between the anatomical regions with the lowest values measured in the pancreatic tail (head 1.13 ± 0.20, body 1.05 ± 0.20, and tail 0.94 ± 0.18 × 10(-3) mm(2) /s; P < 0.05). ANOVA showed no dependency of ADC values on the sets of b-values used.
  
  
  CONCLUSIONS
  ADC values differed significantly between the pancreatic head, body, and tail region, with decreasing ADC values toward the tail. Cautious interpretation of DWI results with adjusted, normalized values adapted to the anatomical region seems advisable. The knowledge of such differences may enhance the method's capability to differentiate between different pancreatic pathologies.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. bschoenn@uke.uni-hamburg.de
authors.forename: Bjoern P
authors.initials: BP
authors.lastname: Schoennagel
authors.forename: Christian R
authors.initials: CR
authors.lastname: Habermann
authors.forename: Magdalena
authors.initials: M
authors.lastname: Roesch
authors.forename: Jasmin D
authors.initials: JD
authors.lastname: Hahne
authors.forename: Christiane
authors.initials: C
authors.lastname: Arndt
authors.forename: Laura
authors.initials: L
authors.lastname: Kleibeler
authors.forename: Kay U
authors.initials: KU
authors.lastname: Petersen
authors.forename: Joachim
authors.initials: J
authors.lastname: Graessner
authors.forename: Gerhard
authors.initials: G
authors.lastname: Adam
authors.forename: Jochen
authors.initials: J
authors.lastname: Herrmann
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015331:Cohort Studies; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000033:anatomy & histology*; D012016:Reference Values; D055815:Young Adult