title: Diffusion-weighted MRI for differentiation of benign from malignant lesions in the gallbladder.
abstract: OBJECTIVE
  To investigate the value of diffusion-weighted imaging (DWI) for differentiating benign from malignant gallbladder lesions.
  
  
  METHODS
  One hundred and twenty-six patients who had undergone magnetic resonance imaging (MRI) with DWI, in whom the histopathological diagnosis of their gallbladder lesions was confirmed by biopsy or surgery were retrospectively analysed. Thirty-six malignant and 90 benign lesions were included. Two radiologists categorized gallbladder lesions into seven types on two imaging sets [T2-weighted imaging (WI) alone and combined T2WI and DWI (b = 800 s/mm(2))] according to the presence of wall thickening, layered patterns, morphology of the mass, and diffusion restriction. Disagreements were resolved in consensus. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each imaging set for diagnosing gallbladder carcinoma were calculated. The diagnostic performance of each imaging set was calculated using receiver operating characteristic (ROC) curve analysis. Additionally, ADC values of malignant and benign gallbladder lesions were compared separately for 1.5 and 3 T MRI.
  
  
  RESULTS
  The sensitivity, specificity, PPV, and NPV of diagnosis at T2WI were 97.2%, 86.7%, 74.5%, and 98.7%, respectively. The sensitivity, specificity, PPV, and NPV using combined T2WI and DWI were 97.2%, 92.2%, 83.3%, and 98.8%, respectively. Diagnostic accuracy for gallbladder carcinoma slightly improved after adding DWI, from 0.92 to 0.95 (p < 0.05). ADC values for gallbladder carcinoma were significantly lower than those for benign lesions. Mean ADC values of malignant and benign lesions were 0.97 ± 0.25 × 10(-3) and 1.72 ± 0.56 × 10(-3) mm(2)/s, respectively, at 1.5 T (p < 0.001), and 1.04 ± 0.38 × 10(-3) and 2.2 ± 0.72 × 10(-3) mm(2)/s, respectively, at 3 T (p < 0.001).
  
  
  CONCLUSIONS
  DWI can improve diagnostic accuracy for differentiating benign from malignant gallbladder lesions.
authors.affiliation: Department of Radiology, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors.forename: N K
authors.initials: NK
authors.lastname: Lee
authors.affiliation: Department of Radiology, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea. Electronic address: kimsuk@medimail.co.kr.
authors.forename: S
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Radiology, Pusan National University School of Medicine, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
authors.forename: T U
authors.initials: TU
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors.forename: D U
authors.initials: DU
authors.lastname: Kim
authors.affiliation: Department of Surgery, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors.forename: H I
authors.initials: HI
authors.lastname: Seo
authors.affiliation: Department of Surgery, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors.forename: T Y
authors.initials: TY
authors.lastname: Jeon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005704:Gallbladder / Q000473:pathology*; D005706:Gallbladder Neoplasms / Q000175:diagnosis*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult