title: Contrast-enhanced ultrasonography for the evaluation of liver fibrosis after biliary obstruction.
abstract: OBJECTIVE
  To investigate perfusion change in contrast-enhanced ultrasonography (CEUS) to evaluate liver fibrosis based on biliary obstruction using an animal model.
  
  
  METHODS
  New Zealand white rabbits (3-4 kg) underwent bile duct ligation to form a biliary obstruction model. We performed liver CEUS and laboratory tests on the day before the operation (day 0) and every 7 postoperative days until the rabbits were sacrificed. After CEUS, signal intensity of liver parenchyma with a time-intensity curve was analyzed. Perfusion parameters were automatically calculated from region-of-interests, including peak signal intensity, mean transit time, area under the curve and time to peak. Histological grades of liver fibrosis were assessed according to the Metavir score system immediately after sacrifice. Generalized estimating equations were used to analyze the association between liver fibrosis grades and perfusion parameters for statistical analysis. The perfusion parameters were measured on the last day and the difference between day 0 and the last day were evaluated.
  
  
  RESULTS
  From the nine rabbits, histological grades of liver fibrosis were grade 1 in one rabbit, grade 2 and 3 in three rabbits each, and grade 4 in two rabbits. Among the four CEUS parameters, only the peak signal intensity measured on the last day demonstrated a significant association with liver fibrosis grades (OR = 1.392, 95%CI: 1.114-1.741, P = 0.004). The difference in peak signal intensity between day 0 and the last day also demonstrated an association with liver fibrosis (OR = 1.191, 95%CI: 0.999-1.419, P = 0.051). The other parameters tested, including mean transit time, area under the curve, and time to peak, showed no significant correlation with liver fibrosis grades.
  
  
  CONCLUSIONS
  This animal study demonstrates that CEUS can be used to evaluate liver fibrosis from biliary obstruction using peak signal intensity as a parameter.
authors.affiliation: Hyun Joo Shin, Hyun Gi Kim, Myung-Joon Kim, Mi-Jung Lee, Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul 120-752, South Korea.
authors.forename: Hyun Joo
authors.initials: HJ
authors.lastname: Shin
authors.affiliation: Hyun Joo Shin, Hyun Gi Kim, Myung-Joon Kim, Mi-Jung Lee, Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul 120-752, South Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Chang
authors.affiliation: Hyun Joo Shin, Hyun Gi Kim, Myung-Joon Kim, Mi-Jung Lee, Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul 120-752, South Korea.
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Hyun Joo Shin, Hyun Gi Kim, Myung-Joon Kim, Mi-Jung Lee, Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul 120-752, South Korea.
authors.forename: Jung Hwa
authors.initials: JH
authors.lastname: Hong
authors.affiliation: Hyun Joo Shin, Hyun Gi Kim, Myung-Joon Kim, Mi-Jung Lee, Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul 120-752, South Korea.
authors.forename: Gyuri
authors.initials: G
authors.lastname: Park
authors.affiliation: Hyun Joo Shin, Hyun Gi Kim, Myung-Joon Kim, Mi-Jung Lee, Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul 120-752, South Korea.
authors.forename: Hyun Gi
authors.initials: HG
authors.lastname: Kim
authors.affiliation: Hyun Joo Shin, Hyun Gi Kim, Myung-Joon Kim, Mi-Jung Lee, Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul 120-752, South Korea.
authors.forename: Myung-Joon
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Hyun Joo Shin, Hyun Gi Kim, Myung-Joon Kim, Mi-Jung Lee, Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul 120-752, South Korea.
authors.forename: Mi-Jung
authors.initials: MJ
authors.lastname: Lee
mesh_terms: D000818:Animals; D002779:Cholestasis / Q000150:complications*; D003287:Contrast Media; D005240:Feasibility Studies; D008099:Liver / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008102:Liver Circulation; D008106:Liver Cirrhosis, Experimental / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008833:Microcirculation; D055420:Perfusion Imaging / Q000379:methods*; D010743:Phospholipids; D011237:Predictive Value of Tests; D011817:Rabbits; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013459:Sulfur Hexafluoride; D013997:Time Factors; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride
keywords: Animals; Bile ducts; Contrast enhanced ultrasound; Ligation; Liver cirrhosis; Rabbits; Ultrasonography