Review for 10.1186/s12876-016-0545-x (2016)

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: 19 Jun 2016 
 
Reviewer:  Yoko  Tomita  
 
Reviewer’s report:  
 
I commend  the large study size and duration, however, the number of incidental uptakes further 
investigated for diagnosis is equivalent to previously published papers and no additional findings 
are achieved here, although it continues to confirm the previously ones . I suggest taking the 
advantage of large case number by doing inferential statistics, exploring the characteristics which 
may be linked with malignant/premalignant lesions (such as SUV which has been looked at by 
others, indication for PET), the change in  the patterns of incidental PET uptake over a time etc. 
A flow chart if not a table describing the number of all PET scans, incidental uptakes, different 
types of uptake or location of uptake all at once may assist readers.  
 
 
Abstract  
 
line 10  
 
how you spell out scientific description of PET "18F -fluorodeoxyglucose ([18F]FDG)" should 
be consistent throughout the paper, in the body it's spelled as 18F -FDG and for the table upper 
case is used  
 
 
Methods  
 
should the advantage of having a large case num ber be maximised by applying inferential 
statistics rather than descriptive statics?  
 
 
Results  
 
I noticed inconsistency with how numbers are spelled. Generally, numbers up to twenty are 
spelled out using alphabets while those above twenty are in numerical.  
 
Page 1 line 10  
 
as the number of PET usage and its technology were thought have improved over time, it will be 
more meaningful if incidence of incidental uptake was expressed as a proportion of total number 
of PET performed per year at least in the table  
Page 1 line 29  
 
EGD should be spelled out fully  
 
Page 2 line 27 - 
 
If PET was performed to identify a primary site of malignancy to explain a pulmonary nodule, 
should the rectal uptake be categorized as an incidental? I'm also uncertain how much value 
inclusi on of a case adds to the whole paper.  
 
Page 2 line 36  
 
"Underwent" is not the suitable verb here  
 
Page 3 line 25 - 
 
Could the rate of a focal uptake being malignant/premalignant/non -neoplastic be compared using 
a statistic test?  
 
 
Discussion  
 
Page 1 line 45  
 
"multiple references" - should still cite the most important ones, otherwise omit this phrase  
 
Page 2 line 4  
 
"likely not indicative" - needs revision of grammar  
 
Page 3 line 45  
 
If constipation is listed as a cause of false positive focal uptake, this is mo re relevant for 
descending colon and that what the reference paper identified.  
 
Page 4  
 
Half of incidental PET uptake were not further investigated this have bearing on the reported 
prevalence of focal uptakes turned out to be malignant/premalignant. This s hould be discussed as 
a limitation of the study.  
 
Page 4 line 12  
 
"update" should be uptake?  
 
Page 4 line 15  
Again please review grammar of the sentence  
 
 
References  
 
Spacing does not appear to be consistent  
 
 
Table 2  
 
Why does the sum of focal uptake no (38) a nd diffuse uptake no (4) in the third column match up 
to non -neoplastic lesions per endoscopy (55). Explanation should be added.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Yes 
 
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.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
 
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 th at I have no competing interest  
 
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