Review
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Jan 28, 2016; 8(1): 59-72
Published online Jan 28, 2016. doi: 10.4329/wjr.v8.i1.59
General review of magnetic resonance elastography
Gavin Low, Scott A Kruse, David J Lomas
Gavin Low, Department of Radiology and Diagnostic Imaging, University of Alberta Hospital, Edmonton AB T6G 2B7, Canada
Scott A Kruse, Department of Radiology, Mayo Clinic, Rochester, MN 55905, United States
David J Lomas, Department of Radiology, Addenbrooke’s Hospital, Cambridge University Hospitals NHS Trust, Cambridge CB2 0QQ, United Kingdom
Author contributions: All authors contributed to the manuscript with collection of data and images, critical revision and editing, and approval of the final version.
Supported by National Institutes of Health, No. R01 EB001981; and National Institute of Health Research Cambridge Biomedical Research Centre.
Conflict-of-interest statement: The authors declare no conflict-of-interests for this article.
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: Gavin Low, MBChB, MPhil, MRCS, FRCR, Department of Radiology and Diagnostic Imaging, University of Alberta Hospital, 2A2.41 WMC, 8440-112 Street, Edmonton AB T6G 2B7, Canada. timgy@yahoo.com
Telephone: +1-780-4076907 Fax: +1-780-4073853
Received: August 28, 2015
Peer-review started: September 1, 2015
First decision: November 6, 2015
Revised: November 14, 2015
Accepted: December 3, 2015
Article in press: December 4, 2015
Published online: January 28, 2016
Processing time: 151 Days and 13.5 Hours
Abstract

Magnetic resonance elastography (MRE) is an innovative imaging technique for the non-invasive quantification of the biomechanical properties of soft tissues via the direct visualization of propagating shear waves in vivo using a modified phase-contrast magnetic resonance imaging (MRI) sequence. Fundamentally, MRE employs the same physical property that physicians utilize when performing manual palpation - that healthy and diseased tissues can be differentiated on the basis of widely differing mechanical stiffness. By performing “virtual palpation”, MRE is able to provide information that is beyond the capabilities of conventional morphologic imaging modalities. In an era of increasing adoption of multi-parametric imaging approaches for solving complex problems, MRE can be seamlessly incorporated into a standard MRI examination to provide a rapid, reliable and comprehensive imaging evaluation at a single patient appointment. Originally described by the Mayo Clinic in 1995, the technique represents the most accurate non-invasive method for the detection and staging of liver fibrosis and is currently performed in more than 100 centers worldwide. In this general review, the mechanical properties of soft tissues, principles of MRE, clinical applications of MRE in the liver and beyond, and limitations and future directions of this discipline -are discussed. Selected diagrams and images are provided for illustration.

Keywords: Magnetic resonance elastography, Elasticity imaging techniques, Liver disease, Fibrosis, Emerging applications

Core tip: Magnetic resonance elastography (MRE) is a non-invasive technique for probing the mechanical properties of biologic tissues. The three main steps involved in the MRE technique include the production of mechanical waves in soft tissues, the adoption of a modified phase-contrast MR sequence to image wave motion, and the application of an inversion algorithm to convert the wave image into an elastogram. MRE has received validation for the non-invasive assessment and grading of fibrosis in chronic liver disease patients. MRE also has potential diagnostic applications in other organ systems and may help further the understanding of disease processes.