Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Mar 7, 2015; 21(9): 2614-2621
Published online Mar 7, 2015. doi: 10.3748/wjg.v21.i9.2614
Contrast-enhanced ultrasonography for the evaluation of liver fibrosis after biliary obstruction
Hyun Joo Shin, Eun Young Chang, Hye Sun Lee, Jung Hwa Hong, Gyuri Park, Hyun Gi Kim, Myung-Joon Kim, Mi-Jung Lee
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
Eun Young Chang, Department of Pediatric Surgery, Severance Children’s Hospital, Yonsei University College of Medicine, Seoul 120-752, South Korea
Hye Sun Lee, Jung Hwa Hong, Biostatistics Collaboration Unit, Yonsei University College of Medicine, Seoul 120-752, South Korea
Gyuri Park, Department of Laboratory Animal Resources, Avison BioMedical Research Center, Yonsei University College of Medicine, Seoul 120-752, South Korea
Author contributions: Lee MJ designed the research; Shin HJ, Chang EY, Park G and Lee MJ performed the research; Shin HJ, Lee HS, Hong JH and Lee MJ contributed analytic tools; Shin HJ, Lee HS, Hong JH and Lee MJ analyzed the data; Shin HJ and Lee MJ wrote the paper; Shin HJ, Kim HG, Kim MJ and Lee MJ revised and approved the final version.
Supported by Faculty Research Grant of Yonsei University College of Medicine for 2013, No. 6-2013-0040.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Mi-Jung Lee, MD, PhD, Department of Radiology and Research Institute of Radiological Science, Severance Children’s Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, South Korea. mjl1213@yuhs.ac
Telephone: +82-2-22287400 Fax: +82-2-3933035
Received: September 12, 2014
Peer-review started: September 13, 2014
First decision: October 14, 2014
Revised: October 24, 2014
Accepted: November 7, 2014
Article in press: November 11, 2014
Published online: March 7, 2015
Processing time: 178 Days and 4.3 Hours
Abstract

AIM: 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.

CONCLUSION: This animal study demonstrates that CEUS can be used to evaluate liver fibrosis from biliary obstruction using peak signal intensity as a parameter.

Keywords: Ultrasonography; Contrast enhanced ultrasound; Liver cirrhosis; Animals; Bile ducts; Ligation; Rabbits

Core tip: Contrast-enhanced ultrasonography (CEUS) was proposed for the evaluation of liver fibrosis. However, no previous studies have evaluated the utility of CEUS for liver fibrosis caused by biliary obstruction, which can be the major cause of liver fibrosis in children. Therefore, we investigated the feasibility of CEUS to evaluate liver fibrosis from biliary obstruction by quantitatively assessing perfusion changes in an animal model with bile duct ligation. We also demonstrated that the parameter of peak signal intensity from CEUS could be useful to evaluate liver fibrosis from biliary obstruction.