Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Aug 27, 2018; 10(8): 530-542
Published online Aug 27, 2018. doi: 10.4254/wjh.v10.i8.530
Current status of imaging in nonalcoholic fatty liver disease
Qian Li, Manish Dhyani, Joseph R Grajo, Claude Sirlin, Anthony E Samir
Qian Li, Manish Dhyani, Anthony E Samir, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, United States
Manish Dhyani, Department of Radiology, Lahey Hospital and Medical Center, 41 Burlington Mall Road, Burlington, MA 01805, United States
Joseph R Grajo, Department of Radiology, Division of Abdominal Imaging, University of Florida College of Medicine, Gainesville, FL 32610, United States
Claude Sirlin, Altman Clinical Translational Research Institute, University of California, San Diego, CA 92103, United States
Author contributions: Both authors have contributed equally to this manuscript and should be considered first co-authors; all authors contributed to this paper with conception and design of the study, literature review and analysis, drafting and critical revision and editing, and final approval of the final version.
Supported by NIBIB of the National Institutes of Health (to Samir C), No. K23 EB020710.
Conflict-of-interest statement: All authors have no conflicts of interest to report.
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:
Correspondence to: Manish Dhyani, MD, Research Associate, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, White 270, Boston, MA 02114, United States.
Telephone: +1-617-8528909
Received: May 21, 2018
Peer-review started: May 21, 2018
First decision: June 5, 2018
Revised: June 25, 2018
Accepted: June 28, 2018
Article in press: June 28, 2018
Published online: August 27, 2018

Non-alcoholic fatty liver disease (NAFLD) is the most common diffuse liver disease, with a worldwide prevalence of 20% to 46%. NAFLD can be subdivided into simple steatosis and nonalcoholic steatohepatitis. Most cases of simple steatosis are non-progressive, whereas nonalcoholic steatohepatitis may result in chronic liver injury and progressive fibrosis in a significant minority. Effective risk stratification and management of NAFLD requires evaluation of hepatic parenchymal fat, fibrosis, and inflammation. Liver biopsy remains the current gold standard; however, non-invasive imaging methods are rapidly evolving and may replace biopsy in some circumstances. These methods include well-established techniques, such as conventional ultrasonography, computed tomography, and magnetic resonance imaging and newer imaging technologies, such as ultrasound elastography, quantitative ultrasound techniques, magnetic resonance elastography, and magnetic resonance-based fat quantitation techniques. The aim of this article is to review the current status of imaging methods for NAFLD risk stratification and management, including their diagnostic accuracy, limitations, and practical applicability.

Keywords: Simple steatosis, Non-alcoholic fatty liver disease, Ultrasonography, Computed tomography, Nonalcoholic steatohepatitis, Elastography, Magnetic resonance

Core tip: Patients with non-alcoholic fatty liver disease (NAFLD) are at risk of steatohepatitis and progressive liver fibrosis culminating in cirrhosis, typically over a period of decades. Early diagnosis and risk stratification are essential for effective management. Current imaging methods such as ultrasound, computed tomography, and magnetic resonance elastography have demonstrated their values to serve as noninvasive imaging biomarkers to evaluate NAFLD progression, but they are still relatively limited in the detection of inflammation, which is more important than steatosis in terms of its high risk for fibrosis, cirrhosis, and hepatocellular carcinoma.