PONE-D-24-36230Cerebral blood flow and histological analysis for the accurate differentiation of infiltrating tumor and vasogenic edema in glioblastomaPLOS ONE

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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: Yes

Reviewer #3: Yes

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

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: Yes

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

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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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: Peer Review Report: Analysis of Cerebral Blood Flow and Histopathology for Differentiation of Infiltrating Tumor and Vasogenic Edema in Glioblastoma

1. Summary of the Study

This manuscript examines the application of dynamic susceptibility contrast (DSC) MRI to distinguish non-contrast-enhancing tumors (NETs) from vasogenic edema in glioblastoma. Using cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) measurements from MRI, coupled with histological data on cell density, Ki-67 index, and microvessel area, the study aims to enhance diagnostic precision. The results highlight significant differences in cell density and vascular characteristics between NETs and edemas, with CBF and MTT being particularly effective in differentiating these regions.

2. Strengths of the Study

Clinical Significance: The study addresses a key issue in the treatment of glioblastoma—accurately differentiating between tumor infiltration and edema. This distinction is vital for improving surgical strategies and overall patient care.

Comprehensive Approach: The study effectively combines advanced imaging techniques with histological validation, lending greater credibility to the findings. The use of stereotactic biopsies ensures accurate correlation between imaging data and tissue pathology.

Innovative Focus: By concentrating on the non-contrast-enhancing regions of glioblastomas, the research tackles a challenging and clinically relevant area that has implications for treatment planning and outcome prediction.

3. Major Concerns

Small Sample Size: The relatively small number of patients (48 with glioblastoma and 24 with meningioma as controls) may limit the robustness and generalizability of the results. Larger studies are necessary to confirm the findings and broaden their applicability.

Limited Discussion on Clinical Impact: Although the study demonstrates the utility of CBF and MTT for differentiating NETs and edemas, there is limited discussion on how these findings could translate into clinical decision-making, particularly in terms of surgical planning or modifying treatment strategies.

Lack of Comparison with Other Modalities: The study would benefit from comparing DSC-MRI with other imaging techniques, such as diffusion-weighted imaging or arterial spin labeling, to better contextualize the advantages and limitations of DSC-MRI in distinguishing tumor from edema.

4. Minor Issues

Clarity of Data Presentation: Some tables and figures, particularly those depicting imaging data, could benefit from more detailed legends and explanations to improve interpretability (e.g., Figure 4).

ROC Analysis Application: While the ROC analysis for CBF and MTT is statistically strong, further elaboration on how these metrics might be applied in clinical settings would enhance the study's practical relevance.

Control Group Explanation: The inclusion of meningioma patients as controls for vasogenic edema is valuable; however, a more thorough explanation of their selection and relevance to glioblastoma would strengthen the rationale for using this group as a comparison.

5. Suggestions for Improvement

Larger Sample Sizes in Future Studies: Expanding the cohort size in future studies would improve the statistical power and help validate the findings across a broader population of glioblastoma patients.

Incorporation of Prognostic Data: Adding data on clinical outcomes, such as patient survival and progression-free intervals, would provide a more comprehensive understanding of the clinical significance of distinguishing NETs from edema using DSC-MRI.

Comparison with Other Imaging Techniques: Including a comparison with alternative imaging modalities could highlight the specific advantages of DSC-MRI and provide a more balanced view of its role in differentiating NETs from edema.

6. Conclusions and Recommendations

The manuscript offers valuable insights into the use of DSC-MRI for distinguishing NETs from vasogenic edemas in glioblastoma. The integration of imaging data with histopathological analysis is a significant strength of the study, and the findings have the potential to impact clinical management. However, the small sample size and limited discussion on clinical applications slightly reduce the study’s overall impact. Expanding the sample size and incorporating additional outcome data would further enhance the value of the research.

Recommendation: The manuscript is a strong candidate for publication, provided revisions are made to address the issues related to sample size, data presentation, and the practical implications of the findings for clinical practice. With these improvements, the study could make a substantial contribution to the field of glioblastoma imaging and treatment.

Reviewer #2: This is an interesting study and the authors have collected a unique dataset using cutting edge methodology.

This paper has good conception and validation in crucial decisions for glioblastoma appraisal. The paper is generally clear and structured. Sufficient information about this study findings is presented for readers to follow the present study rationale and procedures in the flowchart/data processing (Figure 1). Notwithstanding, in my opinion, the paper has some imperfections concerning some data analyses and text, and this unique dataset has not been availed to its full extent.

Key critical points are:

Quantitative and qualitative research for data type approach in statistical results and analysis is important. Especially, Figure 1 is the conception of this study in data analysis. Unfortunately, The reviewer didn't see any tables describing it in sufficient detail.

(1) The biggest issue is that the data analysis should more robust and so, the authors are going to have to find a way to properly demonstrate their data. How about the power analysis in statistics?

(2) The image mark-up plays an important role in results. The Figure 1 is divided into three colors marked segments. What is your groundwork based on these color-marked ?

Ki-67 labeling index is an important indicator of tumor cell proliferation in glioma, which can only be obtained by postoperative biopsy regarding microvascular proliferation as a crucial histological feature of glioblastoma.

(3) Could you show the different ROIs correspondingly in histological features in this study? Additionally, please discuss this point in the Discussion section.

Data Implement

(4) Regarding the edema, T2*-based dynamic susceptibility contrast (DSC) MRI is a good point for approach, however, correlation coefficient value interpretation is weak for low correlation. Could you discuss this part in the discussion?

(5) What else about the study limitations except a small sample size? Please add more in Discussion.

Reviewer #3: PLOS ONE

Ms type: Research Article

Ms ID: PONE-D-24-36230

Title: Cerebral blood flow and histological analysis for the accurate differentiation of infiltrating tumor and vasogenic edema in glioblastoma

General Comments:

The study presents valuable findings regarding the use of DSC-MRI perfusion imaging for differentiating non-contrast-enhancing tumors (NETs) from vasogenic edema in glioblastomas. The correlation observed between CBF and histopathological parameters such as cell density, Ki-67 index, and microvessel area is particularly noteworthy. However, a major point of concern arises from the lack of correlation between CBV and these same parameters, despite the fact that several studies in the literature suggest that CBV is typically more sensitive than CBF in reflecting neovascularization, especially in gliomas.

1. Explanation for the Discrepancy between CBF and CBV: It would be beneficial for the authors to provide a more in-depth explanation or hypothesis as to why CBV did not show a significant correlation with microvessel area, cell density, or Ki-67 index, while CBF did. Given that both CBF and CBV are considered reliable markers of neovascularization, the observed discrepancy raises important questions. In some studies, CBV has been shown to better capture neovascularization than CBF. The authors should address whether the lack of correlation could be due to technical factors, such as the selection of arterial input function (AIF) or the specific post-processing algorithms used in the study, particularly since CBV calculation is known to be more sensitive to such variables.

2. The Role of Vessel Co-option: Additionally, the authors may wish to consider the role of vessel co-option, which is prominent in glioblastomas. Vessel co-option could explain why CBF increases without a corresponding rise in CBV, as pre-existing vasculature is co-opted by infiltrating tumor cells. This phenomenon may result in increased blood flow (CBF) without a significant increase in vessel volume (CBV), particularly in the NET regions. A discussion on whether this mechanism could account for the differential behavior of CBF and CBV would provide valuable context to the findings.

3. Potential Influence of Tumor Stage or Region: It may also be worthwhile to discuss whether the stage of tumor progression or the specific tumor region examined could influence the sensitivity of CBF versus CBV in detecting neovascularization. Early-stage tumors or regions with active infiltration might show different perfusion characteristics than more established tumor regions. Clarifying whether the study accounted for such factors would strengthen the interpretation of the results.

In summary, while the results of the study are promising, addressing the discrepancy between CBF and CBV and providing a more comprehensive discussion on possible reasons for this observation would greatly enhance the robustness and clinical relevance of the findings.

Minor Comments:

4. Presentation of Representative Images: To further enhance the clarity and impact of the study, it would be valuable to include representative images from both glioblastoma and meningioma cases. Specifically, providing clear examples of DSC-MR perfusion images with corresponding CBF, CBV, and MTT maps for typical cases of NETs and Edemas in glioblastoma, as well as for vasogenic edema in meningioma, would help readers better understand the radiological differences described in the study. These images would also visually support the conclusions drawn from the quantitative data and improve the overall comprehensibility of the findings.

5. Inclusion of Color Scale Units and LUT Bars in Figure 1: A minor but important detail for improving the clarity of Figure 1 is the addition of the color scale units and LUT (Lookup Table) bars for the CBV, CBF, and MTT maps. Including these will allow readers to interpret the quantitative perfusion values more effectively. Clear color scales and units are essential for accurately assessing the radiological findings presented and ensuring that the visual data aligns with the statistical analysis discussed in the manuscript.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

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Cerebral blood flow and histological analysis for the accurate differentiation of infiltrating tumor and vasogenic edema in glioblastoma

PONE-D-24-36230R1

Dear Dr. Okita,

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.

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Kind regards,

Pradeep Kumar, Ph.D.

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

Reviewer #3: All comments have been addressed

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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

Reviewer #3: Yes

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

Reviewer #2: Yes

Reviewer #3: Yes

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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

Reviewer #3: Yes

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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

Reviewer #3: Yes

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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: (1) Interesting, What software should make Fig. 6 Representation of the correlation between cell density, Ki-67 index, and microvessel area in ET, NET, and edema for stereotaxic assessment?

(2) Much Better! All comments have been addressed. Thank you for all your hard work!

Reviewer #3: The authors responded to the comments satisfactorily, and the changes improved the quality of the text.

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Reviewer #2: No

Reviewer #3: No

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