Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

1. Thank you for submitting the manuscript. I have a few suggestions that may help improve the clarity of the manuscript.

2. As I understand it, Figure 5 is intended to demonstrate a vessel wall imaging (VWI) sequence. I would recommend explicitly emphasizing this in the figure legend and/or in the main text. It would also be helpful to include a post-contrast VWI sequence, particularly as the vessel wall is better delineated on the post-contrast images.

3. I would suggest expanding the discussion to mention that internal carotid artery (ICA) compression may also occur at this level, particularly in cases of a tortuous ICA or an anatomically high- or low-lying carotid bifurcation.

In these cases, functional/dynamic assessment can be important for establishing the diagnosis, as static imaging may not demonstrate clinically relevant compression, especially when symptoms are positional. A relevant recent case is reported by Bicevska et al., describing functional compression of the ICA by the hyoid bone in a patient with a low ICA bifurcation. doi:10.2147/VHRM.S520022.

4. Please discuss an additional differential diagnosis, with emphasis on the role of dynamic/functional vascular assessment.

5. Reference section is rather limited. I would suggest adding 3–5 more recent clinical reports on carotid artery compression by adjacent structures, including hyoid bone and styloid-related compression, to strengthen the discussion.

 

Author Response

1. Thank you for submitting the manuscript. I have a few suggestions that may help improve the clarity of the manuscript.

response: 

We thank the reviewer for the careful evaluation of our manuscript and for the constructive suggestions, which have helped us improve the clarity of the manuscript. We have addressed each comment individually below.

2. As I understand it, Figure 5 is intended to demonstrate a vessel wall imaging (VWI) sequence. I would recommend explicitly emphasizing this in the figure legend and/or in the main text. It would also be helpful to include a post-contrast VWI sequence, particularly as the vessel wall is better delineated on the post-contrast images.

response: 

We agree that the purpose of Figure 5 should be made more explicit. We have therefore revised the main text and figure legend to identify the 3D T1-weighted SPACE sequence as non-contrast vessel wall imaging. A post-contrast vessel wall sequence was not acquired as part of the clinical imaging protocol and is therefore not available for inclusion. We have clarified the non-contrast nature of the sequence in the revised manuscript.

3. I would suggest expanding the discussion to mention that internal carotid artery (ICA) compression may also occur at this level, particularly in cases of a tortuous ICA or an anatomically high- or low-lying carotid bifurcation.

In these cases, functional/dynamic assessment can be important for establishing the diagnosis, as static imaging may not demonstrate clinically relevant compression, especially when symptoms are positional. A relevant recent case is reported by Bicevska et al., describing functional compression of the ICA by the hyoid bone in a patient with a low ICA bifurcation. doi:10.2147/VHRM.S520022.

response: 

We have expanded the differential diagnosis to include subclavian steal syndrome, an alternative haemodynamic cause of vertebrobasilar symptoms. We have also added a brief discussion emphasizing that intermittent steal may not be apparent on resting imaging and that functional Doppler assessment, including arm exercise or reactive hyperaemia, may reveal transient vertebral flow reversal.

4. Please discuss an additional differential diagnosis, with emphasis on the role of dynamic/functional vascular assessment.

response:

We thank the reviewer for this suggestion. We have expanded the Discussion and reference list with additional recent literature on cervical osteovascular compression. In particular, we added the recent report by Bicevska et al. describing functional ICA compression by the hyoid bone, as well as a recent report of styloid-related ICA compression in stylocarotid artery syndrome. We also added a recent reference addressing functional vascular assessment in an important haemodynamic differential diagnosis. These additions broaden the discussion of carotid and other cervical vascular compression mechanisms and further emphasize the role of dynamic assessment.

5. Reference section is rather limited. I would suggest adding 3–5 more recent clinical reports on carotid artery compression by adjacent structures, including hyoid bone and styloid-related compression, to strengthen the discussion.

response: please refer to the response of the previous comment. 

Reviewer 2 Report

Comments and Suggestions for Authors

Perfusion CT and DWI images were not demonstrated. The relation between VA stenosis and clinical symptoms was not discussed. The strategy of the treatment was not clearly discussed.

Author Response

Perfusion CT and DWI images were not demonstrated.

response : 

We thank the reviewer for this comment. We agree that illustrating the negative brain imaging findings improves the completeness of the case presentation. We have therefore added representative perfusion CT and diffusion-weighted MRI images, demonstrating the absence of focal hypoperfusion and acute ischaemic lesions, respectively, and have cited the new figure in the Imaging Findings section.

The relation between VA stenosis and clinical symptoms was not discussed.

Response: 

We thank the reviewer for this comment. In this case, the relationship between the right vertebral artery stenosis and the patient’s transient neurological symptoms remained uncertain. The neurological events were heterogeneous and occurred spontaneously, without a reproducible relationship to head or neck movement. In addition, perfusion CT showed no focal hypoperfusion, DWI showed no acute ischaemic lesion, and competing embolic risk factors were present. Therefore, although the anatomical vertebral artery compression was clearly demonstrated, we could not confidently establish it as the cause of the patient’s symptoms. This uncertainty is an important aspect of the case and was one of the reasons for avoiding over-attribution of the clinical events to the vertebral artery stenosis.

The strategy of the treatment was not clearly discussed.

Response: 

We thank the reviewer for this comment. The treatment strategy was conservative because the clinical relevance of the vertebral artery stenosis remained uncertain. The patient’s symptoms were not reproducibly related to head or neck movement, perfusion CT and DWI showed no evidence of cerebral ischaemia, and competing embolic risk factors were present. Therefore, there was insufficient evidence to attribute the neurological events to the osteovascular conflict and to justify targeted surgical decompression. In this context, conservative management was considered the most appropriate strategy, with invasive treatment reserved for cases in which a clear causal and haemodynamic relationship between the vascular compression and symptoms can be demonstrated.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for the corrections. Both the article itself and the quality of the images have been improved.

Reviewer 2 Report

Comments and Suggestions for Authors

I recognized significant improvements in this manuscript, so this is acceptable.