title: Role of diffusion-weighted magnetic resonance imaging in the diagnosis of gallbladder cancer.
abstract: OBJECTIVE
  To determine the additional diagnostic value of high b-value diffusion-weighted imaging (DWI) compared to conventional biliary magnetic resonance imaging (MRI) for differentiating gallbladder (GB) cancer from benign GB diseases with wall thickening.
  
  
  METHODS
  Thirty-nine patients with GB cancers and 36 patients with cholecystitis having preoperative biliary MRIs were included. All patients underwent unenhanced T1- and T2-weighted imaging (T2WI), Gd-enhanced dynamic MRI, and DWI (b values 0, 100, 500, 1000 s/mm(2) ). Two radiologists independently analyzed two sets of MRI for characterization of GB lesions: a conventional biliary image (CBI) set with T1- and T2WI and a dynamic image; and a DWI set composed of DWI and a CBI set. Diagnostic accuracy and sensitivity were evaluated using the receiver operator characteristic method. The mean apparent diffusion coefficient (ADC) values of the lesions were also calculated.
  
  
  RESULTS
  The Az values were 0.856 and 0.960 for reviewers 1 and 2, respectively, with the CBI set and increased to 0.952 and 0.983 with the DWI set. The mean ADC value of GB carcinoma was 1.46 ± 0.45 × 10(-3) mm(2) /s and that of cholecysititis was 2.16 ± 0.56 × 10(-3) mm(2) /s (P < 0.0001).
  
  
  CONCLUSIONS
  Adding DWI to the standard biliary MRI protocol may improve sensitivity for distinguishing GB cancers from benign GB diseases with wall thickening.
authors.affiliation: Department of Radiology, National Cancer Center, Goyang-si, Gyeonggi-do, Korea.
authors.forename: Soo Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Hyungjin
authors.initials: H
authors.lastname: Kim
authors.forename: Jeong Hee
authors.initials: JH
authors.lastname: Yoon
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
authors.forename: Byung Ihn
authors.initials: BI
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002764:Cholecystitis / Q000150:complications* / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005706:Gallbladder Neoplasms / Q000150:complications* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: ADC; MRI; cholecystitis; diffusion-weighted imaging; gallbladder cancer