title: Biliary sludge after liver transplantation: 1. Imaging findings and efficacy of various imaging procedures.
abstract: OBJECTIVE
  Biliary sludge (inspissated, thickened bile or collective collagen tissue from destroyed [or necrotic] bile duct walls) can be found a few days to several years after liver transplantation, mainly in the common and main hepatic bile ducts. The purpose of this study was to review the imaging findings of biliary sludge occurring after liver transplantation and to determine the relative merits of various imaging procedures (cholangiography, CT, and sonography) for establishing the diagnosis.
  
  
  METHODS
  Cholangiograms, sonograms, and CT scans obtained in 352 patients with 400 liver transplants were reviewed retrospectively for evidence of biliary sludge. In all patients, T-tube cholangiograms were routinely obtained 7 and 30 days and 3 months after transplantation. Thereafter, in the absence of findings, the T-tube was removed. In all patients, sonograms were obtained immediately, 2 and 7 days after transplantation. Additional cholangiograms were obtained when biliary complications were suspected (T-tube cholangiograms in 215 patients, percutaneous transhepatic cholangiograms in 79 patients, and endoscopic retrograde cholangiograms in five patients after T-tube removal). Additional sonograms were obtained in 289 patients and CT scans in 238 patients when complications were suspected. The findings of these various imaging studies were analyzed and compared with each other, with the clinical course of the patient, and with surgical and histologic findings to determine the relative merits of each imaging method for the diagnosis of biliary sludge. Criteria for the diagnosis of biliary sludge were filling defects or pluglike obstruction seen on cholangiograms or material filling the bile ducts seen on sonograms or CT scans. The radiologic diagnosis of biliary sludge was certified by gross specimens obtained at surgery (n = 21) or autopsy (n = 2) or by complete disappearance of the radiologic findings with specific oral or interventional treatment (n = 28).
  
  
  RESULTS
  Biliary sludge was diagnosed on the basis of radiologic findings in 51 (13%) of 400 transplanted livers. Cholangiograms (T-tube in 34, percutaneous transhepatic cholangiography in seven, a combination of T-tube and percutaneous transhepatic cholangiography in eight, and a combination of endoscopic retrograde and percutaneous transhepatic cholangiography in two cases) showed biliary sludge in all 51 cases. Cholangiographic findings included filling defects in 34 (67%) and obstruction of the bile duct with pluglike appearance in 17 (33%) of the 51 cases. Dilatation of bile ducts was present in 32 (63%) of the 51 cases. The presence of biliary sludge was certified in 50 of these cases, with one case turning out to be a sutural granuloma at autopsy. On sonograms, biliary sludge was shown as echogenic material in the main bile ducts in only 16 (31%) of the 51 cases, with dilatation of bile ducts in 12 of them. In 10 others (20%), sonograms showed dilatation of the bile ducts but did not show the sludge itself. CT scans did not show the sludge in any of the 12 cases in which they were obtained.
  
  
  CONCLUSIONS
  Our results show that cholangiography is the only accurate imaging method for diagnosing biliary sludge after liver transplantation. Sonography is limited and CT is of no value for this purpose. In the absence of a T-tube, endoscopic retrograde or percutaneous transhepatic cholangiography should be used. Otherwise, T-tube cholangiography is the method of choice. Filling defects and obstruction of the bile ducts with pluglike material are characteristic findings of biliary sludge seen on cholangiograms.
authors.affiliation: Department of Radiology, University of Vienna, Medical School, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Barton
authors.forename: A
authors.initials: A
authors.lastname: Maier
authors.forename: R
authors.initials: R
authors.lastname: Steininger
authors.forename: F
authors.initials: F
authors.lastname: Mühlbacher
authors.forename: G
authors.initials: G
authors.lastname: Lechner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001646:Bile / Q000000981:diagnostic imaging*; D001652:Bile Ducts / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D002758:Cholangiography; D002779:Cholestasis / Q000000981:diagnostic imaging* / Q000209:etiology; D005260:Female; D006801:Humans; D016031:Liver Transplantation; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography