title: Malignant versus benign hepatic masses in patients with recurrent pyogenic cholangitis: MR differential diagnosis.
abstract: OBJECTIVE
  To assess MR findings and diagnostic performance for differentiating malignant from benign hepatic masses in recurrent pyogenic cholangitis (RPC).
  
  
  METHODS
  During a recent 6-year period, we performed MRI in 352 patients with RPC. Among them, 58 had confirmed hepatic masses; cholangiocarcinoma (n = 15), abscess (n = 37), inflammatory pseudotumor (n = 3), biloma (n = 3). Two radiologists assessed MR findings including enhancement patterns, intratumoral appearance, peritumoral changes, mass location, and multiplicity. They also graded the malignancy using common MR findings. The receiver operating characteristic analysis and Chi-square test were used. The κ statistics was used to determine interobserver agreement.
  
  
  RESULTS
  The common findings for cholangiocarcinoma were thin and lobulated enhancement at the periphery (n = 8, 53%, P < 0.05); ill-defined enhancement (n = 7, 47%, P < 0.05); slightly high signal on T2 (n = 13, 87%, P < 0.05); mass located in the same lobe of atrophy (n = 11, 73%, P < 0.05) and portal vein thrombosis (n = 15, 100%, P < 0.05). The common findings for benign mass were target-like enhancement (n = 36, 84%, P < 0.05); cluster appearance (n = 15, 35%, P < 0.05); central, fluid-like space (n = 29, 67%, P < 0.05); peritumoral regional high signal on T2 (n = 32, 74%, P < 0.05); multiplicity(n = 21, 49%, P < 0.05). Interobserver agreement was excellent (κ = 0.81-1.000). Area under the curve (Az) for differentiating malignant masses was 0.989, sensitivity was 95.3%, and specificity was 95.3%. There was good interobserver agreement (κ = 0.74).
  
  
  CONCLUSIONS
  MR imaging is very useful for differential diagnosis of malignant vs. benign hepatic masses in patients with RPC.
authors.affiliation: Health Promotion Center, Asan Medical Center, University of Ulsan, 388-1 Poongnap-dong, Songpa-gu, Seoul, 138-736, Korea. namsanae@gmail.com
authors.forename: Hyo Won
authors.initials: HW
authors.lastname: Eun
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Seong Sook
authors.initials: SS
authors.lastname: Hong
authors.forename: Young Jae
authors.initials: YJ
authors.lastname: Kim
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D002761:Cholangitis / Q000150:complications*; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D019786:Gadolinium DTPA; D006498:Hepatectomy; D006801:Humans; D008107:Liver Diseases / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012008:Recurrence
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA