Review for 10.1186/s12876-017-0707-5 (2017)

Reviewer ’s report  
 
Title:  Evaluation of the visibility of early gastric cancer using linked color imaging and blue 
laser imaging  
 
Version: 1 Date: 24 Sep 2017 
 
Reviewer:  Hyunghun  Kim 
 
Reviewer’s report:  
 
Dear Authors  
 
General comment  
 
This is one of studies that I have been waiting for several years. There have been challenges to 
realize software -based electronic IEE. FICE and i -scan we re the representative techniques. 
However, they faded away without remarkable achievement.  
 
LCI is a hard -ware and soft -ware based IEE; enhancing red color while suppressing blue and 
green color component. This idea is based on the observation that most EG C shows more reddish 
color than background mucosa, and some EGC shows more whitish color than background 
mucosa, especially in the case of undifferentiated type. Considering these points, LCI seems 
feasible for detecting a lesion (screening endoscopy).  
 
BLI is another achievement in the case of light source. We do not need a lamp anymore; cost 
effective in terms of durability. Furthermore, BLI, theoretically, can provide clearer image due to 
less interference among lights, because it is basically a laser. T he sad point is that BLI is not a 
first physically equipped narrow band imaging technology. I guess that BLI -BRT might be 
developed for a screening tool. I am very positive for using BLI -BRT for screening pharyngeal 
and esophageal cancer and colorectal ser rated adenoma. However, BLI -BRT can be a week tool 
for screening EGC due to still its lower light intensity; stomach is much larger organ than other 
hollow organs.  
 
Integrating the pieces of information, we can develop an idea that LCI increases the visibi lity of 
EGC compared to WLI, and BLI -BRT can be far inferior than LCI, even can be inferior than 
WLI. However, inductive study is important to verify an idea produced by deductive reasoning. I 
would like to point out several things that need to be consider ed again before deciding to publish 
this paper.  
 
Introduction  
 
# There are two kinds of IEEs. One thing is physically equipped techniques, NBI and BLI. The 
other is soft -ware based IEE such as FICE and i -scan. Please describe two kinds of technique 
specifi cally. In this study, authors are dealing interesting tool, LCI, based on hardware and 
software based IEE.  
 
# Please clarity clinical purpose; why you did this experiment: might be screening purpose. This 
study cannot prove the efficacy of LCI or BLI -BRT as a tool for screening EGC. However, this 
study can provide the bridge between an idea that LCI can be used as a screening tool and the 
study that reveal the true efficacy of LCI for detecting an EGC in screening endoscopy. For this 
reason, I would like t o suggest authors to clarify the clinical purpose of this study before 
mentioning direct purpose of this research.  
 
Method  
 
# Authors should describe how to get images in three modes, WLI, BLI -BRT. LCI.  
 
1) WLI  
 
Please describe every mode when authors did g et image, for example from A1 to B8 and light 
intensity you selected for WLI. Many people outside Japan did not know LASEREO system. 
Please let them know. Did authors use Xenon lamp system? No. White Laser system with 
diffuser! Please describe this.  
 
2) BLI-BRT  
 
Please describe BLI and BLI -BRT as delicate as possible in clinical setting level, not 
complicated engineering. Authors mentioned B8 mode in patient section. I do not think it is 
adequate to mention this information in patient enroll part. Please desc ribe this information in 
independent part.  
 
3) LCI 
 
Please explain the meaning of this sentence more easily.  
 
Since the colors that are more dissimilar to the mucosal color are not moved as much, the colors 
of the processed image better match those seen on a white light image (Figure 1).  
 
This tool is relatively new, so please let readers understand this technolog y easily. Please explain 
by examples.  
 
# I do think that authors want to say that LCI improved the visibility of EGC regardless of the 
level of endoscopists' experience or Hp eradication in patients, particularly for EGCs with a 
reddish or whitish color. F or this conclusion, authors need to set the bottom line; such as "no less 
than 70% increased visibility is regarded as statistically increased visibility". Without this 
setting, it is not reasonable to conclude that LCI improved the visibility of EGC regar dless of the 
level of endoscopists' experience or Hp eradication in patients, particularly for EGCs with a 
reddish or whitish color.  
 
# I kindly suggest authors to analyze which characters of the lesion affect the increased visibility 
of EGC, and in which situation, LCI cannot contribute increased visibility of EGC.  
 
In table 3, isochromic EGC showed only 45% increased visibility. If it is a single arm study with 
isochromic EGC, the efficacy of LCI for detecting isochromic EGCs might be somewhat 
disappointi ng. As authors know well, reddish EGCs and whitish EGCs are relatively easy to 
detect. The trickiest problem is isochromic flat EGCs. Please analyze factors affecting the 
increased visibility of LCI. It is imperative for next tool development.  
 
# I cautio usly suggest authors to analyze which characters of the lesion affect the decrease the 
visibility of EGC in BLI -BRT. Understanding down -side is also important for next generation 
machine development.  
 
Statistical analysis  
 
Please describe which software yo u did use for this study. Moreover, please write down each 
parameter for each statistical method. I understand that is seems redundant, but I think that it is 
better.  
 
Results  
 
# Please add more tables analyzing factors influencing increased visibility of LCI, and factors 
influencing decreased visibility of BLI -BRT.  
 
Discussion  
 
# Please focus on explaining your result.  
 
1) I do think the first paragraph is redundant. Please delete it (page 11 line 1 -4) 
 
2) Please delete this sentence. It is out of scope of  this article. (page 11 line 11 -13) 
 
However, with magnification, BLI enables the detailed observation of mucosal surface 
information about vascular and surface patterns, and enables the qualitative diagnosis of gastric 
cancer. [16]  
 
# Please avoid same wor ds in one sentence.  
 
For example (page 13 line 8 -9) 
 
The present <report> is the first detailed <report> that evaluates the visibility of EGC with LCI 
and BLI. "The present study is the first detailed report… …" I think it is better  
 
# I do think it is better to say your positive imperative result in your conclusion. You can add 
subsidiary findings, but not necessary. Moreover, if you would like to conclude that LCI 
improved the visibility you need to define the bottom line of increase d visibility in methodology 
and result.  
 
This is my suggestion  
 
In conclusion, our study showed LCI improved the visibility of EGC, regardless of the level of 
endoscopists' experience or Hp eradication in patients, particularly for EGCs with a reddish or 
whitish color. The visibility of EGC was not significantly improved with BLI -BRT.  
 
Dear Authors  
 
I would like to say that you did interesting and meaningful study, but please do more for the 
more persuadable paper.  
 
Thank you.  
 
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.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to  assess any statistics 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 statistic s 
 
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 reimbur sements, 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  
 
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