Case Control Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 28, 2015; 21(16): 4894-4902
Published online Apr 28, 2015. doi: 10.3748/wjg.v21.i16.4894
Estimating steatosis and fibrosis: Comparison of acoustic structure quantification with established techniques
Thomas Karlas, Joachim Berger, Nikita Garnov, Franziska Lindner, Harald Busse, Nicolas Linder, Alexander Schaudinn, Bettina Relke, Rima Chakaroun, Michael Tröltzsch, Johannes Wiegand, Volker Keim
Thomas Karlas, Nikita Garnov, IFB Adiposity Diseases, Leipzig University Medical Center, 04103 Leipzig, Germany
Thomas Karlas, Joachim Berger, Franziska Lindner, Michael Tröltzsch, Johannes Wiegand, Volker Keim, Department of Medicine, Neurology and Dermatology, Division of Gastroenterology and Rheumatology, University Hospital Leipzig, 04103 Leipzig, Germany
Nikita Garnov, Harald Busse, Nicolas Linder, Alexander Schaudinn, Department of Diagnostic and Interventional Radiology, University Hospital Leipzig, 04103 Leipzig, Germany
Bettina Relke, Internistische Hausarzt- und Diabetologische Schwerpunktpraxis Dr. Relke, 04249 Leipzig, Germany
Rima Chakaroun, Department of Medicine, Neurology and Dermatology, Division of Endocrinology and Nephrology, University Hospital Leipzig, 04103 Leipzig, Germany
Author contributions: Karlas T and Berger J contributed equally to this work; Karlas T, Berger J, Garnov N, Wiegand J and Keim V designed the research; Karlas T, Berger J, Garnov N, Lindner F, Busse H, Linder N, Schaudinn A, Relke B, Chakaroun R, Tröltzsch M, Wiegand J and Keim V performed the research; Karlas T, Berger J, Garnov N, Busse H, Linder N, Schaudinn A, Wiegand J and Keim V analyzed the data; Karlas T, Berger J, Garnov N, Wiegand J and Keim V wrote the manuscript; Lindner F, Busse H, Linder N, Schaudinn A, Relke B, Chakaroun R and Tröltzsch M revised the manuscript.
Supported by Federal Ministry of Education and Research (BMBF), Germany, FKZ: 01EO1001 (Project No. K7-40); the German Research Foundation (DFG); and the University of Leipzig within the program of Open Access Publishing.
Ethics approval: The study was reviewed and approved by the local ethics committee (University of Leipzig, register no. 358/08-B-ff and no. 419-12-17122012).
Informed consent: All participants provided written informed consent prior to study enrollment.
Conflict-of-interest: TK received travel grants from Echosens (Paris/France). All other authors have nothing to disclose.
Data sharing: Technical appendix, statistical code, and dataset are available from the corresponding author at thomas.karlas@medizin.uni-leipzig.de. No additional data are available.
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: Thomas Karlas, MD, Department of Medicine, Neurology and Dermatology, Division of Gastroenterology and Rheumatology, University Hospital Leipzig, Liebigstrasse 20, 04103 Leipzig, Germany. thomas.karlas@medizin.uni-leipzig.de
Telephone: +49-341-9712200 Fax: +49-341-9712209
Received: October 26, 2014
Peer-review started: October 30, 2014
First decision: December 11, 2014
Revised: January 8, 2015
Accepted: February 11, 2015
Article in press: February 11, 2015
Published online: April 28, 2015
Processing time: 183 Days and 12.8 Hours
Abstract

AIM: To compare ultrasound-based acoustic structure quantification (ASQ) with established non-invasive techniques for grading and staging fatty liver disease.

METHODS: Type 2 diabetic patients at risk of non-alcoholic fatty liver disease (n = 50) and healthy volunteers (n = 20) were evaluated using laboratory analysis and anthropometric measurements, transient elastography (TE), controlled attenuation parameter (CAP), proton magnetic resonance spectroscopy (1H-MRS; only available for the diabetic cohort), and ASQ. ASQ parameters mode, average and focal disturbance (FD) ratio were compared with: (1) the extent of liver fibrosis estimated from TE and non-alcoholic fatty liver disease (NAFLD) fibrosis scores; and (2) the amount of steatosis, which was classified according to CAP values.

RESULTS: Forty-seven diabetic patients (age 67.0 ± 8.6 years; body mass index 29.4 ± 4.5 kg/m²) with reliable CAP measurements and all controls (age 26.5 ± 3.2 years; body mass index 22.0 ± 2.7 kg/m²) were included in the analysis. All ASQ parameters showed differences between healthy controls and diabetic patients (P < 0.001, respectively). The ASQ FD ratio (logarithmic) correlated with the CAP (r = -0.81, P < 0.001) and 1H-MRS (r = -0.43, P = 0.004) results. The FD ratio [CAP < 250 dB/m: 107 (102-109), CAP between 250 and 300 dB/m: 106 (102-114); CAP between 300 and 350 dB/m: 105 (100-112), CAP ≥ 350 dB/m: 102 (99-108)] as well as mode and average parameters, were reduced in cases with advanced steatosis (ANOVA P < 0.05). However, none of the ASQ parameters showed a significant difference in patients with advanced fibrosis, as determined by TE and the NAFLD fibrosis score (P > 0.08, respectively).

CONCLUSION: ASQ parameters correlate with steatosis, but not with fibrosis in fatty liver disease. Steatosis estimation with ASQ should be further evaluated in biopsy-controlled studies.

Keywords: Transient elastography; Non-alcoholic fatty liver disease; Liver stiffness; Non-alcoholic fatty liver disease; Fibrosis score; Controlled attenuation parameter

Core tip: Non-invasive characterization of hepatic steatosis and fibrosis is becoming important for the screening, diagnosis, and monitoring of patients with chronic liver diseases. This work compared acoustic structure quantification (ASQ) and established non-invasive methods to characterize fatty liver disease. ASQ parameters differed between healthy controls and diabetic patients with fatty liver disease independent of the extent of fibrosis. The focal disturbance ratio and further ASQ parameters correlated with the severity of steatosis. Therefore, ASQ could be used to evaluate steatosis and merits further investigation; however, ASQ seems to be impractical to characterize fibrosis in patients with fatty liver disease.