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World J Gastroenterol. Dec 14, 2022; 28(46): 6512-6521
Published online Dec 14, 2022. doi: 10.3748/wjg.v28.i46.6512
Factors other than fibrosis that increase measured shear wave velocity
Hiroko Naganuma, Hideaki Ishida
Hiroko Naganuma, Department of Gastroenterology, Yokote Municipal Hospital, Yokote 013-8602, Japan
Hideaki Ishida, Department of Gastroenterology, Akita Red Cross Hospital, Akita 010-1495, Japan
Author contributions: Ishida H performed the majority of the writing; Naganuma H prepared the figures and schemas and performed writing.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Hiroko Naganuma, MD, PhD, Doctor, Department of Gastroenterology, Yokote Municipal Hospital, Negishi-cho 5-31, Yokote 013-8602, Japan. hiron@vesta.ocn.ne.jp
Received: September 14, 2022
Peer-review started: September 14, 2022
First decision: October 19, 2022
Revised: October 27, 2022
Accepted: November 21, 2022
Article in press: November 21, 2022
Published online: December 14, 2022
Processing time: 84 Days and 19.4 Hours
Abstract

Shear wave elastography (SWE) is now becoming an indispensable diagnostic tool in the routine examination of liver diseases. In particular, accuracy is required for shear wave propagation velocity measurement, which is directly related to diagnostic accuracy. It is generally accepted that the liver shear wave propagation velocity reflects the degree of fibrosis, but there are still few reports on other factors that increase the shear wave propagation velocity. In this study, we reviewed such factors in the literature and examined their mechanisms. Current SWE measures propagation velocity based on the assumption that the medium has a homogeneous structure, uniform density, and is purely elastic. Otherwise, the measurement is subject to error. The other (confounding) factors that we routinely experience are primarily: (1) Conditions that appear to increase the viscous component; and (2) Conditions that appear to increase tissue density. Clinically, the former includes acute hepatitis, congested liver, biliary obstruction, etc, and the latter includes diffuse infiltration of malignant cells, various storage diseases, tissue necrosis, etc. In any case, it is important to evaluate SWE in the context of the entire clinical picture.

Keywords: Liver; Shear wave elastography; Propagation velocity; Viscoelasticity; Artifact; Ultrasound

Core Tip: Shear wave elastography (SWE) has become an indispensable diagnostic tool for diagnosing liver disease patients. The shear wave propagation velocity usually reflects the degree of fibrosis, but we must keep in mind other (confounding) factors. The confounding factors due to viscosity include acute hepatitis, congestive liver, and biliary stasis. The other confounding factors due to an increase of tissue density include diffuse infiltration of malignant cells, various storage diseases, and tissue necrosis. It is important to judge SWE results in the context of the entire clinical picture.