Reviewer ’s report  
 
Title: Clinical Significance of Incidental [18F]FDG Uptake in the Gastrointestinal Tract on 
PET/CT Imaging: A Retrospective Cohort Study  
 
Version: 0 Date: 02 Jun 2016 
 
Reviewer:  Michael  Lin 
 
Reviewer’s report:  
 
General comments:  
 
There are many papers on this topic including several reviews. Focal large bowel uptake on FDG 
PET needing further investigations to exclude dysplastic polyp and colorectal cancer is well 
known.  
 
 
Specific comments:  
 
There is a slight discrepancy between the title and results. I presume the paper is more about 
focal uptake in the GIT. There is very limited description regarding other patterns of uptake (eg. 
diffuse, segmental) and what they turned out to represent or whether further investigations were 
indeed performed.  
 
The methodology section is brief and does not contain sufficient i nformation , eg. the different 
patterns of FDG uptake at different locati ons, should be stated. The tables can be expanded and 
improved.  
 
How was incidental GIT uptake determined? I presume higher than background? How was 
diffuse uptake interpreted, ie. between normal vs abnormal?  
 
It is well known the metformin can cause diffus e reactive bowel uptake and the number of 
patients on this medication would be helpful. Did these patients have diffuse uptake  and did any 
of these patients undergo colonoscopy?  
 
In results, the inclusion of SUV measurements and the T stage of the incident al carcinomas 
found would be helpful.  
 
Intro - page 5 line 36, polyp is a neoplastic condition  
 
Method and Results - Apart from the colorectum, the other sites of incidental GIT uptake needed 
to be clarified. Location? Pattern? Aetiology?  
 
Page 8 - first paragra ph is confusing  
In the discussion "Fasting can increase focal uptake of 18F -FDG as well [16]" - I am uncertain 
this is true and a more recent study to support this statement would be helpful. If not, should be 
taken out.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
No 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any st atistics in the manuscript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further 
assessment in your comments to the editors.  
 
Not relevant to this manuscript  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an 
organisation that may in any way gain or lose financially from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in  any way gain or lose 
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the 
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds or has applied for patents relating to the content of the manuscript?  
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below. If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests . 
 
I agree to the open peer review policy of the journa l. I understand that my name will be included 
on my report to the authors and, if the manuscript is accepted for publication, my named report 
including any attachments I upload will be posted on the website along with the authors' 
responses. I agree for my  report to be made available under an Open Access Creative Commons 
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments 
which I do not wish to be included in m y named report can be included as confidential comments 
to the editors, which will not be published . 
 
I agree to the open peer review policy of the journal  
Reviewer ’s report  
 
Title: Clinical Significance of Incidental [18F]FDG Uptake in the Gastrointestinal Tract on 
PET/CT Imaging: A Retrospective Cohort Study  
 
Version: 0 Date: 02 Jun 2016 
 
Reviewer:  Michael  Lin 
 
Reviewer’s report:  
 
General comments:  
 
There are many papers on this topic including several reviews. Focal large bowel uptake on FDG 
PET needing further investigations to exclude dysplastic polyp and colorectal cancer is well 
known.  
 
 
Specific comments:  
 
There is a slight discrepancy between the title and results. I presume the paper is more about 
focal uptake in the GIT. There is very limited description regarding other patterns of uptake (eg. 
diffuse, segmental) and what they turned out to represent or whether further investigations were 
indeed performed.  
 
The methodology section is brief and does not contain sufficient i nformation , eg. the different 
patterns of FDG uptake at different locati ons, should be stated. The tables can be expanded and 
improved.  
 
How was incidental GIT uptake determined? I presume higher than background? How was 
diffuse uptake interpreted, ie. between normal vs abnormal?  
 
It is well known the metformin can cause diffus e reactive bowel uptake and the number of 
patients on this medication would be helpful. Did these patients have diffuse uptake  and did any 
of these patients undergo colonoscopy?  
 
In results, the inclusion of SUV measurements and the T stage of the incident al carcinomas 
found would be helpful.  
 
Intro - page 5 line 36, polyp is a neoplastic condition  
 
Method and Results - Apart from the colorectum, the other sites of incidental GIT uptake needed 
to be clarified. Location? Pattern? Aetiology?  
 
Page 8 - first paragra ph is confusing  
In the discussion "Fasting can increase focal uptake of 18F -FDG as well [16]" - I am uncertain 
this is true and a more recent study to support this statement would be helpful. If not, should be 
taken out.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
No 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any st atistics in the manuscript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further 
assessment in your comments to the editors.  
 
Not relevant to this manuscript  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an 
organisation that may in any way gain or lose financially from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in  any way gain or lose 
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the 
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds or has applied for patents relating to the content of the manuscript?  
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below. If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests . 
 
I agree to the open peer review policy of the journa l. I understand that my name will be included 
on my report to the authors and, if the manuscript is accepted for publication, my named report 
including any attachments I upload will be posted on the website along with the authors' 
responses. I agree for my  report to be made available under an Open Access Creative Commons 
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments 
which I do not wish to be included in m y named report can be included as confidential comments 
to the editors, which will not be published . 
 
I agree to the open peer review policy of the journal  
Please review this paper.
user
Reviewer ’s report  
 
Title: Clinical Significance of Incidental [18F]FDG Uptake in the Gastrointestinal Tract on 
PET/CT Imaging: A Retrospective Cohort Study  
 
Version: 0 Date: 02 Jun 2016 
 
Reviewer:  Michael  Lin 
 
Reviewer’s report:  
 
General comments:  
 
There are many papers on this topic including several reviews. Focal large bowel uptake on FDG 
PET needing further investigations to exclude dysplastic polyp and colorectal cancer is well 
known.  
 
 
Specific comments:  
 
There is a slight discrepancy between the title and results. I presume the paper is more about 
focal uptake in the GIT. There is very limited description regarding other patterns of uptake (eg. 
diffuse, segmental) and what they turned out to represent or whether further investigations were 
indeed performed.  
 
The methodology section is brief and does not contain sufficient i nformation , eg. the different 
patterns of FDG uptake at different locati ons, should be stated. The tables can be expanded and 
improved.  
 
How was incidental GIT uptake determined? I presume higher than background? How was 
diffuse uptake interpreted, ie. between normal vs abnormal?  
 
It is well known the metformin can cause diffus e reactive bowel uptake and the number of 
patients on this medication would be helpful. Did these patients have diffuse uptake  and did any 
of these patients undergo colonoscopy?  
 
In results, the inclusion of SUV measurements and the T stage of the incident al carcinomas 
found would be helpful.  
 
Intro - page 5 line 36, polyp is a neoplastic condition  
 
Method and Results - Apart from the colorectum, the other sites of incidental GIT uptake needed 
to be clarified. Location? Pattern? Aetiology?  
 
Page 8 - first paragra ph is confusing  
In the discussion "Fasting can increase focal uptake of 18F -FDG as well [16]" - I am uncertain 
this is true and a more recent study to support this statement would be helpful. If not, should be 
taken out.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
No 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any st atistics in the manuscript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further 
assessment in your comments to the editors.  
 
Not relevant to this manuscript  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an 
organisation that may in any way gain or lose financially from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in  any way gain or lose 
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the 
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds or has applied for patents relating to the content of the manuscript?  
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below. If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests . 
 
I agree to the open peer review policy of the journa l. I understand that my name will be included 
on my report to the authors and, if the manuscript is accepted for publication, my named report 
including any attachments I upload will be posted on the website along with the authors' 
responses. I agree for my  report to be made available under an Open Access Creative Commons 
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments 
which I do not wish to be included in m y named report can be included as confidential comments 
to the editors, which will not be published . 
 
I agree to the open peer review policy of the journal  
assistant