title: Apparent diffusion coefficient measurements of the pancreas, pancreas carcinoma, and mass-forming focal pancreatitis.
abstract: BACKGROUND
  Mass-forming focal pancreatitis (FP) may mimic pancreatic cancer (PC) on magnetic resonance (MR) imaging, and the preoperative differential diagnosis is often difficult. Recently, the usefulness of diffusion-weighted imaging (DWI) in the diagnosis of pancreatic cancer has been reported in several studies.
  
  
  OBJECTIVE
  To investigate if apparent diffusion coefficient (ADC) measurements based on diffusion-weighted echo-planar imaging (DW-EPI) may distinguish between normal pancreas parenchyma, mass-forming focal pancreatitis, and pancreas carcinoma.
  
  
  METHODS
  MRI was performed on 64 patients: 24 with pancreas carcinoma (PC), 20 with mass-forming focal pancreatitis (FP), three patients with other focal pancreatic disease as well as 17 controls without any known pancreatic disease. Diffusion-weighted sequence with ADC maps and T2-weighted sequence for anatomical information was performed. Apparent diffusion coefficient (ADC) maps were automatically created and analyzed using a dedicated user interface. In the group with pancreas disease the abnormal parenchyma was detected by using T1- and T2-weighted images and the region of interest (ROI) was transferred exactly to the ADC map and the coefficients were registered. In the control group the ROI was set to the head of the pancreas followed by a similar registration of the ADCs.
  
  
  RESULTS
  ADC values for mass-forming FP and PC differed significantly from ADC values for normal pancreas parenchyma (P = 0.001/P = 0.002). Mean ADC values for mass-forming FP were 0.69 ± 0.18 × 10(-3) mm(2)/s. ADC values for PC were 0.78 ± 0.11 × 10(-3) mm(2)/s, compared to ADC values of 0.17 ± 0.06 × 10(-3) mm(2)/s in the control group. However there was no significant difference in ADCs between PC and mass-forming FP (P = 0.15).
  
  
  CONCLUSIONS
  ADC measurements clearly differentiated between normal pancreatic tissue and abnormal pancreas parenchyma (PC and mass-forming FP). However there is an overlap in values of PC and mass-forming FP, with the consequent problem of their correct identification.
authors.affiliation: University Medical Center Regensburg, Institute of Diagnostic Radiology, Germany. philipp.wiggermann@ukr.de
authors.forename: Philipp
authors.initials: P
authors.lastname: Wiggermann
authors.forename: Robert
authors.initials: R
authors.lastname: Grützmann
authors.forename: Angelika
authors.initials: A
authors.lastname: Weissenböck
authors.forename: Peter
authors.initials: P
authors.lastname: Kamusella
authors.forename: Dag-Daniel
authors.initials: DD
authors.lastname: Dittert
authors.forename: Christian
authors.initials: C
authors.lastname: Stroszczynski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D049448:Cholangiopancreatography, Magnetic Resonance / Q000379:methods; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010179:Pancreas / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000473:pathology*; D010195:Pancreatitis / Q000473:pathology*
chemical_list: D003287:Contrast Media; D005682:Gadolinium