title: Diagnostic value of T1-weighted gradient-echo in-phase images added to MRCP in differentiation of hepatolithiasis and intrahepatic pneumobilia.
abstract: OBJECTIVE
  The purpose of this article is to determine the added diagnostic value of T1-weighted gradient-echo in-phase images obtained during MRCP in the detection and differentiation of hepatolithiasis and intrahepatic pneumobilia.
  
  
  METHODS
  Intrahepatic bile ducts in 47 patients were scored in terms of their possibility of containing biliary stone and air. MRI was performed with a 1-T system for 32 patients and with a 3-T system for 15 patients. Two radiologists independently reviewed two sets of MRI scans: set 1 included T2-weighted MRCP images, and set 2 included T2-weighted MRCP images plus T1-weighted gradient-echo in-phase images. The diagnostic performances of set 1 and set 2 in the evaluation of the bile ducts containing air or stone and bile ducts containing neither of them were analyzed using the area under the receiver operating characteristic curve (AUC) for clustered data. The sensitivities and specificities of both image sets to detect intrahepatic stone or air were also calculated and compared.
  
  
  RESULTS
  For the diagnosis of hepatolithiasis, the AUC obtained from set 2 (0.983) was significantly higher than that obtained from set 1 (0.879; p = 0.037). For the diagnosis of pneumobilia, the AUC obtained from set 2 (0.965) was also significantly higher than that of set 1 (0.765; p = 0.002). With use of percutaneous transhepatic cholangiography, ERCP, and CT as the reference standards, the sensitivity of set 2 (97.1%; 95% CI, 91.1-100%) was significantly higher than that of set 1 (74.3%; 95% CI, 56.7-91.9%) in detecting intrahepatic stones (p = 0.011). For the detection of pneumobilia, the sensitivity of set 2 (98.5%; 95% CI, 95.4-100%) was also significantly higher than that of set 1 (70.8%; 95% CI, 57.7-83.3%; p = 0.000).
  
  
  CONCLUSIONS
  The addition of T1-weighted gradient-echo in-phase images to standard MRCP sequences improves the detection and differentiation of hepatolithiasis and intrahepatic pneumobilia.
authors.affiliation: 1 Department of Radiology, School of Medicine, Ankara University, Talatpaşa Bulvari, Sihhiye, 06100, Ankara, Turkey.
authors.forename: Ayşe
authors.initials: A
authors.lastname: Erden
authors.forename: Nuray
authors.initials: N
authors.lastname: Haliloğlu
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Genç
authors.forename: Ilhan
authors.initials: I
authors.lastname: Erden
mesh_terms: D000328:Adult; D000368:Aged; D001653:Bile Ducts, Intrahepatic; D001660:Biliary Tract Diseases / Q000175:diagnosis* / Q000209:etiology; D049448:Cholangiopancreatography, Magnetic Resonance / Q000379:methods*; D003937:Diagnosis, Differential; D005260:Female; D042882:Gallstones / Q000175:diagnosis*; D005740:Gases; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D005740:Gases