Consistency of superb microvascular imaging and contrast-enhanced ultrasonography in detection of intraplaque neovascularization: A meta-analysis.

This meta-analysis assesses the consistency of superb microvascular imaging (SMI) and contrast-enhanced ultrasonography (CEUS) in detecting intraplaque neovascularization (IPN). We searched PubMed, Web of Science, the Cochrane Library, and CBM databases. A meta-analysis was conducted using STATA version 15.1 software. We calculated the pooled Kappa index. Ten studies that met all of the inclusion criteria were included in this meta-analysis. A total of 608 carotid plaques were assessed through both SMI and CEUS. The pooled summary Kappa index was 0.743 (95% confidence interval (CI) = 0.696-0.790) with statistical significance (z = 31.14, P < 0.01). We found no evidence of publication bias (t = -1.21, P = 0.261). Our meta-analysis indicates that SMI and CEUS display a good consistency in detecting the IPN of carotid plaque; that is, SMI ultrasound may be a promising alternative to CEUS for detecting the IPN of carotid plaque.

Introduction

In today’s society, the incidence of atherosclerosis is high, and it is trending younger [1]. Atherosclerotic plaques can cause carotid artery stenosis and affect the blood supply to the brain from the carotid artery to the brain, and vulnerable carotid atherosclerotic plaques are prone to rupture, bleeding, and the formation of thrombi, which can enter the blood vessels of the brain with the blood, causing ischemic stroke events [2]. Stroke is a common refractory disease that seriously endangers human health and lives [3]. The development of atherosclerotic plaque seriously affects the outcome and prognosis of the disease, and there is a significant consistency between intraplaque neovascularization (IPN) and atherosclerotic plaque vulnerability, so the IPN can be used as a risk factor to evaluate the vulnerability of plaque [4]. Contrast-enhanced ultrasonography (CEUS) can indicate IPN effectively, but it is an invasive examination requiring injection of a contrast medium [5]. Superb microvascular imaging (SMI) is a new ultrasonic diagnosis technology that uses adaptive principles to display low-speed blood flow signals [6]. Several studies had suggested that SMI, which is a promising noninvasive alternative, can be used to detect IPN with accuracy comparable to CEUS [7]. However, the results of these studies have been contradictory and the sample sizes were small. Therefore, we performed the present meta-analysis to assess the consistency of SMI and CEUS in detecting intraplaque IPN.

Methods

Literature search

We searched PubMed, Web of Science, the Cochrane Library, and CBM databases. The following search terms were used: [carotid] and [plaques or plaque or fatty streak or fibroatheroma] and [contrast-enhanced ultrasound or contrast-enhanced ultrasonography or contrast ultrasonography or ultrasound contrast imaging or CEUS] and [vulnerability or stability or neovascularization] and [superb microvascular imaging]. We also reviewed references from eligible articles for additional relevant studies.

Selection criteria

The eligible studies were required to match all the following criteria: (1) the study design must be a clinical cohort study, (2) the study must relate to the comparison of CEUS and SMI for detecting IPN, (3) intraplaque microvascular flow (IMVF) were be graded, and (4) published data in the row x column tables must be sufficient for Kappa index and standard error. In cases of sequential and duplicate publications, we included the most recent work with the largest sample size.

Data extraction

The following data were extracted from each included study by two reviewers independently: year of article, the first author’s surname, sample size, number of IMVF grades, Kappa index, and standard error.

Quality assessment

Methodological quality was independently assessed by two researchers using a tool for the assessment of the quality of methodological indexes for nonrandomized studies (MINORS). The MINORS criteria included 12 assessment items. Each of these items was scored as “yes” (2), “no” (0), or “unclear” (1). MINORS score ranged from 0 to 24; and a score ≥ 17 indicated good quality.

Statistical analysis

The software STATA version 15.1 (Stata Corporation, College Station, Texas, USA) was used for meta-analysis. We calculated the pooled summary Kappa index and its 95% confidence interval (CI). The Cochran’s Q-statistic and I2 test were used to evaluate potential heterogeneity between studies [8]. If a Q test showed a P < 0.05 or I2 test exceeded 50%, which indicates significant heterogeneity, the random effect model or fixed effects model was used. Sensitivity analysis was performed to evaluate the influence of each individual study on the overall estimate. The Begg’s funnel plot and Egger’s test were used to assess publication bias [9].

Results

Characteristics of included studies

Overall, 10 studies (Table 1) that met all of the inclusion criteria were included in this meta-analysis. Fig 1 shows the selection process of the eligible articles. A total of 608 carotid plaques were assessed through both SMI and CEUS. MINORS scores of all the included studies were 17.

Table 1

Baseline characteristics and methodological quality of all included studies.

First Author	Year	Sample Size	Gender (M/F)	Age (Years)	IMVF Grade Number	Kappa Index	SE (Kappa)	MINORS Score
Ma et al. [10]	2018	55	34/12	61±7	4	0.734	0.072	18
Chen [11]	2016	80	40/16	64.1±8.2	4	0.755	0.059	19
Zhang et al. [12]	2019	60	29/14	62.9±7.0	4	0.650	0.076	18
Ding et al. [13]	2019	62	50/12	61.59±9.16	3	0.769	0.068	18
Cheng et al. [14]	2015	57	44/13	61.8±7.8	3	0.607	0.127	19
Dong et al. [15]	2018	69	39/30	67.38±8.61	3	0.689	0.105	17
Zhang et al. [16]	2017	39	27/12	60±4	3	0.860	0.076	17
Yan [17]	2018	33	——	——	4	0.621	0.103	19
Xie et al. [18]	2018	108	53/16	68.1±8.8	4	0.748	0.054	20
Wang et al. [19]	2019	45	33/12	61.42±7.37	4	0.839	0.090	18

M, male; F, female; IMVF, intraplaque microvascular flow; SE, standard error; MINORS, methodological index for nonrandomized studies.Quantitative data synthesis

Fig 1

Flow chart of literature search and study selection.

Ten studies were included in this meta-analysis.

Quantitative data synthesis

The fixed effects model was used whenever there was a lack of obvious heterogeneity among the studies (I2 = 0%, P = 0.531). Sensitivity analysis was carried out, and none of them caused obvious interference to the results of this meta-analysis (Fig 2). The pooled summary Kappa index was 0.743 (95% CI = 0.696−0.790) with statistical significance (z = 31.14, P < 0.01), which indicated that SMI and CEUS have a good consistency in detecting IPN of carotid plaque (Fig 3). The funnel plots indicated little evidence of significant publication bias (Fig 4), and Egger’s test confirmed this (t = 1.21, P = 0.261).

Fig 2

Sensitivity analysis.

No one factor caused obvious interference with the results.

Fig 3

Forest plots of Kappa index for superb microvascular imaging (SMI) in the detection of intraplaque neovascularization (IPN) comparable to contrast-enhanced ultrasonography (CEUS).

Fig 4

Begger’s funnel plot of publication bias on the pooled Kappa.

No publication bias was detected in this meta-analysis.

Discussion

Carotid atherosclerotic plaque is closely related to cerebrovascular events. It directly affects structure and composition of plaque, which indicates the occurrence and development of subsequent ischemic cerebrovascular events [20]. Those unstable plaques that readily rupture, fall off, and cause distal embolism are called vulnerable plaques [21]. The morphological characteristics of vulnerable plaques include the following: irregular plaque surface or ulcer formation, thin fiber cap or fissure, bleeding, high concentrations of lipids and inflammatory active components, and neovascularization in the plaque [22]. Neovascularization plays a central role in plaque initiation, progression, and rupture and is a predictor of plaque instability and stroke risk [23]. Histopathological evidence shows that, unlike with relatively stable plaques, the presence and density distribution of neovascularization in plaques are closely related to plaque rupture, and neovascularization is often located in the fibrous cap fissure area and in areas with lipid enrichment and active inflammation. The detection of neovascularization in plaque can be used to evaluate the stability of atherosclerotic plaque and even predict the occurrence of cardiovascular and cerebrovascular diseases [24]. Finding a convenient, safe, and reproducible imaging method that could be used to determine the stability of arterial plaque has long been the focus of clinical research.

Conventional two-dimensional ultrasound and color Doppler ultrasound can be used to observe and measure the echo, shape, and thickness of a plaque and evaluate the degree of vascular stenosis caused by plaque, but they cannot evaluate the stability of plaque comprehensively and accurately, whereas CEUS has high spatial and temporal resolution, and microbubbles have the same fluidity as red blood cells. Some scholars use CEUS to detect neovascularization in plaque as reliable evidence for the diagnosis of vulnerable plaque [25, 26]. However, because of the high cost of contrast media, trauma examination, and the risk of allergy of contrast media, CEUS is limited to some extent. It is necessary to find a simple, noninvasive, and inexpensive method of ultrasound examination.

SMI technology is based on high-resolution Doppler technology. We used Aplio series upmarket ultrasonic diagnostic equipment to build a high-density beamformer and real-time application platform and image the low-flow-velocity blood flow with a high frame rate. Traditional Doppler ultrasound uses filtering technology to eliminate noise and motion artifacts, resulting in the loss of low-speed blood flow information. SMI technology can identify the noise generated by blood flow and tissue movement, and it uses adaptive calculation to display real-time blood flow information, so that the low-speed blood flow signals can be separated from filtered clutter signals and displayed [27]. Recent studies have indicated that SMI is a simpler, safer, cheaper, and noninvasive technique and may facilitate the visualization of carotid artery IPN without the use of a contrast agent [7, 14]. However, no quantitative evaluations of IMVF signal in SMI have been performed, and the relationship between SMI findings and degree of enhancement on CEUS remain unclear. At present, there is a lack of multicenter, large-sample research. This study aims to provide a comprehensive and reliable conclusion on the consistency of SMI and CEUS in detecting IPN.

In the present meta-analysis, we systematically evaluated the technical performance and the consistency of SMI and CEUS in detecting IPN. Finally, 10 independent studies were included with a total of 608 carotid plaques assessed. The pooled summary Kappa index was 0.743 with statistical significance. Furthermore, our results indicated no direct evidence for publication bias. Taken together, consistent with previous studies, our findings strongly suggest that SMI and CEUS display a good consistency in detecting IPN of carotid plaque; that is, SMI ultrasound may be a promising alternative to CEUS for detecting IPN of carotid plaque.

However, this work does have several limitations. First, the included studies were mainly performed in China, which may have caused selection bias due to ethnicity factors. Although existing systematic reviews have suggested that the inclusion of articles published in Chinese alone would not affect the overall effect direction, the exclusion of publications in other languages may reduce the precision of the summary effect estimates [28]. However, many of the studies did not address whether the grades of SMI and CEUS interacted with blinding. Empirical evidence suggests that lack of blinding tends to cause overestimation of the treatment effect [29]. This indicates that even if bias is introduced by the lack of blinding, the true Kappa index would be even smaller than the results generated by this meta-analysis. Meta-analyses are retrospective studies, which may lead to subject selection bias. Therefore, more well-designed, large, multicenter, prospective, double-blind control studies should be conducted to validate these findings in future studies.

In conclusion, our meta-analysis suggests that SMI and CEUS display a good consistency in detecting IPN.

PRISMA 2009 checklist.

(DOC)

Click here for additional data file.

18 May 2020

PONE-D-20-06672

Consistency of superb microvascular imaging and contrast enhanced ultrasonography in detecting intraplaque neovascularization: a meta-analysis

PLOS ONE

Dear Mr. Wang,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

We would appreciate receiving your revised manuscript by Jul 02 2020 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Dalin Tang

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. We noticed you have some minor occurrence of overlapping text with the following previous publication(s), which needs to be addressed:

https://doi.org/10.1007/s13277-014-1815-2

In your revision ensure you cite all your sources (including your own works), and quote or rephrase any duplicated text outside the methods section. Further consideration is dependent on these concerns being addressed

3. PLOS requires an ORCID iD for the corresponding author in Editorial Manager on papers submitted after December 6th, 2016. Please ensure that you have an ORCID iD and that it is validated in Editorial Manager. To do this, go to ‘Update my Information’ (in the upper left-hand corner of the main menu), and click on the Fetch/Validate link next to the ORCID field. This will take you to the ORCID site and allow you to create a new iD or authenticate a pre-existing iD in Editorial Manager. Please see the following video for instructions on linking an ORCID iD to your Editorial Manager account: https://www.youtube.com/watch?v=_xcclfuvtxQ

4. Please include your tables as part of your main manuscript and remove the individual files. Please note that supplementary tables (should remain/ be uploaded) as separate "supporting information" files

5. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: .

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: No

Reviewer #2: No

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The ms. by Yang et al. is aimed at demonstrating that superb microvascular imaging and contrast enhanced ultrasonography are comparable in detecting intraplaque neovascularization. The authors performed a thorough literature research. Findings are clinical relevant and may pave the way for clinical application.

Overall, the finding is convincing and the manuscript well-written. However, method description and language are not always optimal.

My concerns are:

1) Did all studies use the same device from one manufacturer? What’s the potential impact on conclusion?

2) Did the interrater-reliability studies include especially concerning about the grading?

3) Is it possible to examine the plaque in the same plane comparing both methods?

4) Authors should make appropriate changes to the language in standard English.

Reviewer #2: The authors indicated that SMI would be a promising alternative to CEUS for detecting IPN of carotid plaque by meta-analysis, which seemed to be significant and useful to evaluate the stability of atherosclerosis plaque and predict the risk of cerebrovascular diseases becauses of its noninvasive, safe and convenient characteristics.

However, there are some problems and issues:

First, all the included 10 literatures were published in Chinese journals. How do the authors control the publication bias if there is only one kind of language literatures? Actually, there may be some international literatures which would meet the inculsion criteria. For example if such papers were published in one language neighter in chinese nor in English, but met the inclusion criteria.

Second, in the 10 literatures, some of the results were given double-blind evaluation by different doctors, others were not, how about the rate of deviation and heterogeneity caused by such issue?

Third, in the discussion part, though the authors indicate the limitations of this meta-analysis, there are no detailed measures to salvage them. The authors should address the objective reasons of the questions, and give some suggestions for next work.

In addition, there are some inappropriate sentences and words in the manuscript. Such as, in the first sentence of the Introduction part: “In today’s society, ….to be younger” and in the seventh sentence of this paragraph: “Several studies had…comparable to CEUS”, and so on. It seemed the English expression was incorrect. Please make serious changes of the language by someone with expertise in technical English editing before resubmitting.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

5 Jun 2020

Journal Requirements:

1.Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming.

OK.

2.We noticed you have some minor occurrence of overlapping text with the following previous publication(s), which needs to be addressed:

Appropriate modifications have been made.

3.PLOS requires an ORCID iD:

OK.

4.Please include your tables as part of your main manuscript and remove the individual files. Please note that supplementary tables (should remain/ be uploaded) as separate "supporting information" files.

OK.

5.Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly.

OK.

Reviewer #1:

1)Did all studies use the same device from one manufacturer? What’s the potential impact on conclusion?

Yes, superb microvascular imaging(SMI; Toshiba Medical Systems Corporation, Tochigi, Japan).

All devices are from Toshiba aplio series color ultrasonic diagnostic instrument, which may reduce sources of heterogeneity.

2)Did the interrater-reliability studies include especially concerning about the grading?

No, the main statistical indicator is Kappa index. Risk of bias within studies was assessed through MINORS.

3)Is it possible to examine the plaque in the same plane comparing both methods?

Not always. Ultrasound usually scans in multiple sections, and takes the section with the most blood flow.

4) Authors should make appropriate changes to the language in standard English.

OK.

Reviewer #2:

First, all the included 10 literatures were published in Chinese journals. How do the authors control the publication bias if there is only one kind of language literatures? Actually, there may be some international literatures which would meet the inculsion criteria. For example if such papers were published in one language neighter in chinese nor in English, but met the inclusion criteria.

We have searched PubMed, Web of Science, Cochrane Library, and CBM databases in fact, but only the 10 literatures are eligible. The Begg’s funnel plot and Egger’s test were applied to assess the publication bias. We have add descriptionin ‘Although existing systematic reviews have suggested that the inclusion of articles published in Chinese alone would not affect the overall effect direction, the exclusion of publications in other languages may reduce the precision of the summary effect Estimates’ in the discussion part.

Second, in the 10 literatures, some of the results were given double-blind evaluation by different doctors, others were not, how about the rate of deviation and heterogeneity caused by such issue?

Empirical evidence suggests that lack of blinding tends to lead to overestimation of the treatment effect. This implies that even if bias is introduced by the lack of blinding, the true Kappa index would be even smaller than the results generated by this systematic review.

Third, in the discussion part, though the authors indicate the limitations of this meta-analysis, there are no detailed measures to salvage them. The authors should address the objective reasons of the questions, and give some suggestions for next work.

OK.

In addition, there are some inappropriate sentences and words in the manuscript. Such as, in the first sentence of the Introduction part: “In today’s society, ….to be younger” and in the seventh sentence of this paragraph: “Several studies had…comparable to CEUS”, and so on. It seemed the English expression was incorrect. Please make serious changes of the language by someone with expertise in technical English editing before resubmitting.

OK.

Submitted filename: Response to Reviewers.docx

Click here for additional data file.

2 Jul 2020

PONE-D-20-06672R1

Consistency of superb microvascular imaging and contrast-enhanced ultrasonography in detection of intraplaque neovascularization: A meta-analysis

PLOS ONE

Dear Dr. Wang,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Aug 16 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Dalin Tang

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This manuscript has been improved. The authors have addressed all my comments. I don't have further comments.

Reviewer #2: The authors have made lots of modification of the manuscript according to the comments.

In the Discussion part about limitations some suggestions should be mentioned for next work.

Please make further careful polish of language.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

4 Jul 2020

1.In the Discussion part about limitations some suggestions should be mentioned for next work.

Answer:OK.--line160-162.

2.Please make further careful polish of language.

Answer:OK.

3.While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool.

Answer:OK.

Submitted filename: Response to Reviewers.rtf

Click here for additional data file.

14 Jul 2020

Consistency of superb microvascular imaging and contrast-enhanced ultrasonography in detection of intraplaque neovascularization: A meta-analysis

PONE-D-20-06672R2

Dear Dr. Wang,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Dalin Tang

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: The authors addressed all the concerns.

They added some limitations of this study in the discussion part and analyzed them well.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: No

16 Jul 2020

PONE-D-20-06672R2

Consistency of superb microvascular imaging and contrast-enhanced ultrasonography in detection of intraplaque neovascularization: A meta-analysis

Dear Dr. Wang:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Professor Dalin Tang

Academic Editor

PLOS ONE