title: Diffusion tensor magnetic resonance imaging of the pancreas.
abstract: OBJECTIVE
  To develop a diffusion-tensor-imaging (DTI) protocol that is sensitive to the complex diffusion and perfusion properties of the healthy and malignant pancreas tissues.
  
  
  METHODS
  Twenty-eight healthy volunteers and nine patients with pancreatic-ductal-adenocacinoma (PDAC), were scanned at 3T with T2-weighted and DTI sequences. Healthy volunteers were also scanned with multi-b diffusion-weighted-imaging (DWI), whereas a standard clinical protocol complemented the PDAC patients' scans. Image processing at pixel resolution yielded parametric maps of three directional diffusion coefficients λ1, λ2, λ3, apparent diffusion coefficient (ADC), and fractional anisotropy (FA), as well as a λ1-vector map, and a main diffusion-direction map.
  
  
  RESULTS
  DTI measurements of healthy pancreatic tissue at b-values 0,500 s/mm² yielded: λ1 = (2.65±0.35)×10⁻³, λ2 = (1.87±0.22)×10⁻³, λ3 = (1.20±0.18)×10⁻³, ADC = (1.91±0.22)×10⁻³ (all in mm²/s units) and FA = 0.38±0.06. Using b-values of 100,500 s/mm² led to a significant reduction in λ1, λ2, λ3 and ADC (p<.0001) and a significant increase (p<0.0001) in FA. The reduction in the diffusion coefficients suggested a contribution of a fast intra-voxel-incoherent-motion (IVIM) component at b≤100 s/mm², which was confirmed by the multi-b DWI results. In PDACs, λ1, λ2, λ3 and ADC in both 0,500 s/mm² and 100,500 s/mm² b-values sets, as well as the reduction in these diffusion coefficients between the two sets, were significantly lower in comparison to the distal normal pancreatic tissue, suggesting higher cellularity and diminution of the fast-IVIM component in the cancer tissue.
  
  
  CONCLUSIONS
  DTI using two reference b-values 0 and 100 s/mm² enabled characterization of the water diffusion and anisotropy of the healthy pancreas, taking into account a contribution of IVIM. The reduction in the diffusion coefficients of PDAC, as compared to normal pancreatic tissue, and the smaller change in these coefficients in PDAC when the reference b-value was modified from 0 to 100 s/mm², helped identifying the presence of malignancy.
authors.affiliation: Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Noam
authors.initials: N
authors.lastname: Nissan
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Institute of Oncology, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Talia
authors.initials: T
authors.lastname: Golan
authors.affiliation: Unit of Biological Services, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Edna
authors.initials: E
authors.lastname: Furman-Haran
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Division of Diagnostic Imaging, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Sara
authors.initials: S
authors.lastname: Apter
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Division of Diagnostic Imaging, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Yael
authors.initials: Y
authors.lastname: Inbar
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Department of Hepato-Pancreato-Biliary Surgery, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Arie
authors.initials: A
authors.lastname: Ariche
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Department of Hepato-Pancreato-Biliary Surgery, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Barak
authors.initials: B
authors.lastname: Bar-Zakay
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Department of Hepato-Pancreato-Biliary Surgery, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Goldes
authors.affiliation: Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Department of Pathology, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Schvimer
authors.affiliation: Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Dov
authors.initials: D
authors.lastname: Grobgeld
authors.affiliation: Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Hadassa
authors.initials: H
authors.lastname: Degani
mesh_terms: D000328:Adult; D000368:Aged; D021441:Carcinoma, Pancreatic Ductal / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000473:pathology*; D010865:Pilot Projects