Computed Tomography Imaging Features of Pulmonary Sequestration

Round 1

Reviewer 1 Report

Dear the authors

I am really grateful for being given this opportunity to review the article, entitled “Computed tomography imaging features of pulmonary sequestration”.

In accordance with the guidelines for reviewers, I would like to describe two comments shown below for authors of this research.

1.                   Page 2, line 74 and 76; PA cases, PA presented. What is “PA”?  The authors are strongly encouraged to spell out the full forms at first mention for this abbreviation.

2.                   The study presented is very important from the view point of medical education, summarizing the imaging features of the supplying arteries and draining vessels in patients with pulmonary sequestration (PS) with an aim to assist with timely clinical diagnosis and operation guidance. Once we read through the study presented, we could be familiar with radiological characteristic of PS, which could be a nice guide for surgery.

Author Response

I am really grateful for being given this opportunity to review the article, entitled “Computed tomography imaging features of pulmonary sequestration”.

In accordance with the guidelines for reviewers, I would like to describe two comments shown below for authors of this research.

1. Page 2, line 74 and 76; PA cases, PA presented. What is “PA”?  The authors are strongly encouraged to spell out the full forms at first mention for this abbreviation.

Reply: Apologies for the error as it should be PS, and this has been corrected.

2. The study presented is very important from the view point of medical

education, summarizing the imaging features of the supplying arteries and draining vessels in patients with pulmonary sequestration (PS) with an aim to assist with timely clinical diagnosis and operation guidance. Once we read through the study presented, we could be familiar with radiological characteristic of PS, which could be a nice guide for surgery.

Reply: Thanks for comment. We are very grateful to the reviewer for acknowledging our research. As suggested we provide a more detailed summary in the Conclusion.

Reviewer 2 Report

Drs. Yang and colleagues present a manuscript on CT features of pulmonary sequestration. The study included 54 cases of intralobar and one case of extralobar sequestration (ILS, ELS). The study is well conducted and the results provided contribute to the existing literature. However, there are aspects in this study which requires improvement and corrections:

1. ILS in many cases is associated with congenital pulmonary adenomatoid malformation (type II most often). The authors refer to cystic changes, which most often represent CPAM. This should be evaluated in their cases. 

2. In many cases of ILS there is bronchial atresia, a feature which should be seen by CT scans; was this present in this study?

3. ILS does not have a connection to the trachea nor has an own trachea, but rather has its segmental bronchus, which will show atresia in many cases. 

4. The authors reported an arterial supply from the descending aorta; in the reviewer’s experience there is a much more variation in the arterial supply, the arteries coming from thoracic interna, intercostal arteries, and many others. The authors describe other sources from the literature. They should comment about their finding. The celiac trunk is abdominal and very likely will be a source for ELS not for ILS.

5. The authors reported, that many cases were incorrectly diagnosed before operation, which is not surprising. Can the authors provide more clear which features from a regular CT scan might guide the surgeons to think about PS. Angiography is usually in thoracic surgery not a routine procedure. What is the impact of cystic structures, when taking into account the combination with CPAM?

Minor to moderate language edition should be done during the production

Author Response

Drs. Yang and colleagues present a manuscript on CT features of pulmonary sequestration. The study included 54 cases of intralobar and one case of extralobar sequestration (ILS, ELS). The study is well conducted and the results provided contribute to the existing literature. However, there are aspects in this study which requires improvement and corrections:

1. ILS in many cases is associated with congenital pulmonary adenomatoid malformation (type II most often). The authors refer to cystic changes, which most often represent CPAM. This should be evaluated in their cases. 

Reply:

Congenital Pulmonary Airway Malformation (CPAM) and pulmonary sequestration (PS) Congenital Lung Malformation (CLM) is also congenital lung malformation. They are often confused with each other because they both have a occupying effect on adjacent mediastinal structures and tend to occur in the lower lobe[1]. ILS is one type of PS, which is supplied by abnormal systemic circulation and drained by pulmonary vein. The blood flow in CPAM is mainly supplied by pulmonary artery and drained by pulmonary vein. Several retrospective pathological case series in fetuses and infants have shown that PS is commonly associated with CPAM type II, a combination of lesions that is relatively rare and has aortic blood supply and pulmonary venous drainage[2]. But CPAM is an overgrowth of the terminal bronchioles resulting in an abnormal connection to the tracheobronchial tree, while PS is a nonfunctional lung mass with no connection to the bronchial tree. We reviewed the findings of this study: no pathological changes of CPAM were found in the part of the cases confirmed by pathology, and no abnormal connection of the mass to the bronchus was found on CT in the cases confirmed by DSA. This has been added in the Discussion.

2. In many cases of ILS there is bronchial atresia, a feature which should be seen by CT scans; was this present in this study?

Reply:

Thanks for comment. Bronchial atresia (BA) usually occurs near the central area of the lung, most commonly in the left upper lobe of the lung, and bronchial mucus plugs are often seen in the distal atresia segment. BA is a lack of communication between the central airway and segmental or subsegmental bronchus. The decrease of pulmonary artery blood supply and hyperinflation in the corresponding area of BA lead to local emphysema, while PS is also local pulmonary artery hypoplasia and bronchial stenosis leading to distal bronchiectasis and emphysema. In PS, BA is reasonable and inevitable, but there are certain differences with the typical  Imaging findings of BA. If BA  occurs below the subsegmental level, it is difficult to distinguish whether the bronchial occlusion caused by repeated bronchial infection in PS or the inherent BA. As shown in Figure 6, a bronchial atresia in the lesion of the left inferior lobe of the lung (white arrow). Figure 7 is another example showing the bronchus in the lower lobe of the right lung was significantly dilated, the bronchial wall was significantly thickened (black arrow), and the formation of mucus embolus in the local bronchial lumen resulted in localized bronchial occlusion.

3. ILS does not have a connection to the trachea nor has an own trachea, but rather has its segmental bronchus, which will show atresia in many cases. 

Reply:

Thanks for comment. For the answer to this question, please see the answer to previous question.

4. The authors reported an arterial supply from the descending aorta; in the reviewer’s experience there is a much more variation in the arterial supply, the arteries coming from thoracic interna, intercostal arteries, and many others. The authors describe other sources from the literature. They should comment about their finding. The celiac trunk is abdominal and very likely will be a source for ELS not for ILS.

Reply:

We agree to reviewer’s comments on the variation of blood supply. In our study, we noticed that 12.7% artery support was from celiac axis which is higher than that reported by Wei and Li (16) with only one case having celiac trunk as the artery support to PS. This was discussed in the revised discussion section.

5. The authors reported, that many cases were incorrectly diagnosed before operation, which is not surprising. Can the authors provide more clear which features from a regular CT scan might guide the surgeons to think about PS. Angiography is usually in thoracic surgery not a routine procedure. What is the impact of cystic structures, when taking into account the combination with CPAM?

Reply: Thank you for your comment. CT images of pulmonary sequestration are varied and may be cystic, solid, or solid. The abnormal lung tissue of ILS is mostly cystic type, which is usually located in the posterior spine of the lower lobe, and some can see the gas-liquid plane, and the cystic cavity is small and looks like "honeycomb". The leaf shape showed a clear boundary soft tissue mass shadow, mostly located in the subdiaphragm. Enhanced CT showing abnormal systemic circulation supplying arteries is a key sign in the diagnosis of PS. The effect of PS combined with CPAM on the cystic structure is not well understood, because we have not seen it in the clinic, and this needs to be collected in the future for further study. This was emphasized in the conclusion with some suggestions to guide clinical diagnosis.

Reviewer 3 Report

1,The study provides valuable insights into the comprehensive computed tomography (CT) analysis of patients with pulmonary sequestration (PS). However, it would be beneficial to include a larger sample size to enhance the statistical power and generalize the findings to a broader population. This would further strengthen the significance and reliability of the reported results.

2,While the paper mentions the symptoms associated with PS, it would be helpful to include more information about the diagnostic methods and treatment options for this condition. Elaborating on the imaging techniques used for diagnosis, such as CT protocols or other modalities, as well as discussing the recommended management strategies, would enhance the clinical relevance and practical implications of the study.

Author Response

1.The study provides valuable insights into the comprehensive computed tomography (CT) analysis of patients with pulmonary sequestration (PS). However, it would be beneficial to include a larger sample size to enhance the statistical power and generalize the findings to a broader population. This would further strengthen the significance and reliability of the reported results.

Reply: Thank you for your comment. We are very grateful to the reviewer for acknowledging our research. In future studies, we will collect more cases for more in-depth research to make the research results more accurate and reliable. Given the fact of rare occurrence of PS, it is challenging to obtain large sample size. Even with relatively small size in this study, we still think our findings have clinical value and impact on increasing awareness of PS diagnosis.

2. While the paper mentions the symptoms associated with PS, it would be helpful to include more information about the diagnostic methods and treatment options for this condition. Elaborating on the imaging techniques used for diagnosis, such as CT protocols or other modalities, as well as discussing the recommended management strategies, would enhance the clinical relevance and practical implications of the study.

Reply: Thank you for the comments. Details of CT scanning protocols are provided in the revised methodology section including scanning and contrast medium protocols. Treatment options were briefly mentioned in the study limitations.

References

1. Kunisaki SM. Narrative review of congenital lung lesions. Transl Pediatr. 2021;10(5):1418-1431.
2. Wang D, Wheeler WB. A hybrid lesion of intralobar sequestration with mixed features of CPAM type I and type II unmasked following SARS-CoV-2 infection: Case report and literature review. Int J Surg Case Rep. 2022;96:107336.
3. Naumeri F, Sajjad MN. Hybrid Lesion: Extralobar Sequestration with Cystic Adenomatoid Malformation - Misdiagnosed as Pulmonary Tuberculosis. J Coll Physicians Surg Pak. 2018;28(9):S204-S206.

Round 2

Reviewer 2 Report

Drs. Yang and colleagues present a revised manuscript. Most of my suggestions were ignored. The comment about CPAM in the discussion is insufficient. The authors need to clearly explain what they did to exclude CPAM. Usually a pathological examination is done for the resected sequestration and therefore a statement about CPAM is included.

English should be improved

Author Response

Response: We thank the reviewer for providing these comments and suggestions. We have responded to the your comments in our previous revision, such as adding a section in Discussion on CPAM as we did not see any case in our study. We added another paragraph on the number of cases of pulmonary isolation syndrome combined with bronchial atresia in our study group, as well as two figures. We hope we have addressed these comments satisfactorily.