Meta-Analysis
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 21, 2020; 26(23): 3304-3317
Published online Jun 21, 2020. doi: 10.3748/wjg.v26.i23.3304
Value of intravoxel incoherent motion in detecting and staging liver fibrosis: A meta-analysis
Zheng Ye, Yi Wei, Jie Chen, Shan Yao, Bin Song
Zheng Ye, Yi Wei, Jie Chen, Shan Yao, West China School of Medicine, Sichuan University, Chengdu 610041, Sichuan Province, China
Bin Song, Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
Author contributions: Ye Z contributed to the conception and design of the study, carried out acquisition, analysis, and interpretation of data, and drafted the article; Wei Y and Chen J interpreted the data and revised the article; Yao S carried out acquisition, analysis, and interpretation of data; Song B contributed to the conception and design of the study and final approval; All authors approved the final version of the article.
Supported by the National Nature Science Foundation of China, No. 81771797 and No. 81971571; and the 1.3.5 Project for Disciplines of Excellence, West China Hospital, Sichuan University, No. ZYJC18008.
Conflict-of-interest statement: The authors have no conflicts of interest to declare.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
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: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Bin Song, PhD, Chief Doctor, Department of Radiology, West China Hospital, Sichuan University, No. 37 Guoxue Alley, Chengdu 610041, Sichuan Province, China. songb_radiology@163.com
Received: December 30, 2019
Peer-review started: December 30, 2019
First decision: February 18, 2020
Revised: March 26, 2020
Accepted: May 29, 2020
Article in press: May 29, 2020
Published online: June 21, 2020
Processing time: 173 Days and 23.1 Hours
ARTICLE HIGHLIGHTS
Research background

Liver fibrosis (LF) is a common pathological feature of all chronic liver diseases. Liver biopsy is the current reference standard in detecting and staging LF. However, liver biopsy is invasive, observer dependent, and prone to sampling variability, all of which hampers its widespread use in clinical practice; thus, a noninvasive method to quantify LF is urgently needed. Recently, magnetic resonance imaging techniques have been increasingly applied to LF detection and staging and could possibly be the noninvasive alternative to liver biopsy. With the accumulation of extracellular matrix in the fibrotic liver, the true molecular water diffusion and perfusion-related diffusion would be restricted. Intravoxel incoherent motion (IVIM) could capture the information of tissue diffusivity and microcapillary perfusion separately and reflect the fibrotic severity with diffusion coefficients.

Research motivation

IVIM, a bi-exponential model based on diffusion-weighted imaging, allows for the separate evaluation of true molecular diffusion and perfusion-related diffusion. Although several recent studies focused on the diagnostic performances of IVIM in LF staging, the reported results were discrepant among studies

Research objectives

With more eligible studies and patients included, the purpose of this meta-analysis is to investigate the diagnostic performance of IVIM in different LF stages with histology as reference.

Research methods

A comprehensive literature search was conducted to identify studies on the diagnostic accuracy of IVIM for assessment of histology proven LF. The stages of LF were classified as F0 (no fibrosis), F1 (portal fibrosis without septa), F2 (periportal fibrosis with few septa), F3 (septal fibrosis) and F4 (cirrhosis), according to histopathological findings. Data were extracted to calculate the pooled sensitivity, specificity, positive and negative likelihood ratios and diagnostic odds ratio, as well as the area under the summary receiver operating characteristic curve (AUC) in each group.

Research results

Twelve studies with 923 subjects were included in this meta-analysis with 5 studies (n = 465) for LF ≥ F1, 9 studies (n = 757) for LF ≥ F2, 4 studies (n = 413) for LF ≥ F3 and 6 studies (n = 562) for LF = F4. The pooled sensitivity and specificity were estimated to be 0.78 (95% confidence interval: 0.73-0.82) and 0.81 (0.74-0.86) for LF ≥ F1 detection with IVIM; 0.82 (0.79-0.86) and 0.80 (0.75-0.84) for staging F2 fibrosis; 0.85 (0.79-0.90) and 0.83 (0.77-0.87) for staging F3 fibrosis, and 0.90 (0.84-0.94) and 0.75 (0.70-0.79) for detecting F4 cirrhosis, respectively. The AUCs for LF ≥ F1, F2, F3, F4 detection were 0.862 (0.811-0.914), 0.883 (0.856-0.909), 0.886 (0.865-0.907) and 0.899 (0.866-0.932), respectively. Moderate to substantial heterogeneity was observed with inconsistency index (I2) ranging from 0% to 77.9%. No publication bias was detected.

Research conclusions

IVIM is a noninvasive tool with good diagnostic performance in detecting and staging LF. Optimized and standardized IVIM protocols are needed for further improving its diagnostic accuracy in clinical practice.

Research perspectives

The results showed that IVIM is a valuable tool in noninvasively detecting and staging LF. However, field strength, the number and distribution of b-values, as well as the triggering methods would affect the diagnostic accuracy. There is still a need to establish an optimized and standardized IVIM protocol for LF diagnosis in clinical practice.