Observational Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Apr 6, 2019; 7(7): 839-848
Published online Apr 6, 2019. doi: 10.12998/wjcc.v7.i7.839
Value of superb micro-vascular imaging in predicting ischemic stroke in patients with carotid atherosclerotic plaques
De-Bin Yang, Jie Zhou, Lan Feng, Rong Xu, Ying-Chun Wang
De-Bin Yang, Jie Zhou, Lan Feng, Rong Xu, Ying-Chun Wang, Department of Ultrasonic Imaging, Jiading District Central Hospital Affiliated Shanghai University of Medicine & Health Sciences, Shanghai 201800, China
Author contributions: Yang DB, Zhou J, Feng L, Xu R and Wang YC contributed to the manuscript design and manuscript writing; All authors approved the final version of the manuscript.
Supported by Shanghai Jiading District Health and Family Planning Commission Health Planning Commission Scientific Research Project, No. KYXM, 2015-KY-02.
Institutional review board statement: The study was approved by the ethics committee of Jiading District Central Hospital Affiliated Shanghai University of Medicine & Health Sciences.
Informed consent statement: All patients gave informed consent.
Conflict-of-interest statement: The authors declare that they have no competing interests.
Data sharing statement: No additional data are available.
STROBE statement: The authors have read the STROBE Statement, and the manuscript was prepared and revised according to the STROBE Statement.
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/
Corresponding author: Ying-Chun Wang, MD, Chief Doctor, Department of Ultrasonic Imaging, Jiading District Central Hospital Affiliated Shanghai University of Medicine & Health Sciences, No. 1 Chengbei Road, Shanghai 201800, China. wangyingchun4478@163.com
Telephone: +86-21-67073318
Received: January 16, 2019
Peer-review started: January 16, 2019
First decision: March 10, 2019
Revised: March 14, 2019
Accepted: March 16, 2019
Article in press: March 16, 2019
Published online: April 6, 2019
ARTICLE HIGHLIGHTS
Research background

Patients with carotid atherosclerotic plaque are prone to ischemic stroke because plaques gradually block blood vessels and cause stroke. Secondly, unstable plaques are prone to rupture and form thrombi, which in turn leads to ischemic stroke. Contrast-enhanced ultrasound (CEUS) can be used to assess unstable plaques because it can detect blood flow in the plaque. However, CEUS is complicated, requires the use of contrast agents and requires the support of nurses, so it cannot be used as a large-scale screening tool for unstable plaques.

Research motivation

Superb micro-vascular imaging (SMI) is a new technique for detecting micro-vascular blood flow, enabling the detection of low-speed micro-vessels. It is expected to be a screening tool for unstable plaques. However, there are few reports on the evaluation of neovascularization in plaques by SMI. Whether it can be used to predict ischemic stroke in patients with carotid plaque is still inconclusive.

Research objectives

In this study, the distribution of micro-vascular blood flow in carotid atherosclerotic plaques was detected by the SMI technique. The aim of this study is to compare the accuracy of SMI and CEUS in predicting ischemic stroke, and to explore the value of SMI in predicting ischemic stroke in patients with unstable carotid plaque.

Research methods

Patients with carotid plaques (luminal stenosis of 50%-70%) were recruited as the subjects in the present study. The clinical baseline data, serological data, CEUS and SMI data were recorded. All patients were followed up for 3 years. During the follow-up period, patients only underwent conservative drug treatment to prevent an ischemic stroke caused by excessive plaque growth within 3 years. According to whether or not ischemic stroke occurred during the follow-up period, the patients were divided into the stroke group and the non-stroke group. The differences in clinical data between the two groups were compared. The correlation between SMI and CEUS was analyzed. The value of SMI and CEUS in predicting ischemic stroke in patients with carotid atherosclerotic plaque within 3 years was explored.

Research results

In the present study, there were 43 patients in the stroke group and 82 patients in the non-stroke group. Patients in the stroke group were mainly in SMI level II and III, while patients in the non-stroke group were mainly in SMI level 0 and I. Cox regression showed that SMI level and enhancement intensity were the independent factors influencing ischemic stroke. SMI level was positively correlated with enhancement intensity. The area under curve of SMI level and enhancement intensity predicting ischemic stroke was 0.878 and 0.890. It indicated that SMI was as good as CEUS in predicting ischemic stroke in patients with unstable carotid plaque. As the SMI level gradually increased, the incidence of ischemic stroke gradually increased. SMI level II revealed the highest accuracy of predicting ischemic stroke in patients with carotid plaque.

Research conclusions

SMI can assess neovascularization in unstable plaques just like CEUS, but SMI is non-invasive and simple to operate. Hence, it can be used as a non-invasive tool for screening for unstable plaques. It can be applied to the clinical diagnosis and prevention of ischemic stroke.

Research perspectives

This study further plans to establish a rabbit carotid atherosclerotic plaque model. The anatomical results of experimental rabbits will be used as criteria for plaque rupture, and the value of SMI and CEUS for predicting unstable plaque rupture will be more accurately analyzed.