Title: Title # Endoscopic nasobiliary drainage-based saline-injection ultrasound: an  imaging
technique for remnant stone detection after retrograde cholangiopancreatography
Version: 2 Date: 24 Aug 2021
Reviewer's report:
Thank you for opportunity of review this article, the tile of “Endoscopic nasobiliary drainage-
based saline-injection ultrasound: a novel imaging technique for remnant stone detection after
retrograde cholangiopancreatography”. Authors described the usefulness of US examination
using ENBD tube saline injection, and the detection rate of residual stones are significantly
increased compared to US alone. Similar article “The Value of Contrast-Enhanced Ultrasound-
Guided Contrast Injection via the Endoscopic Nasobiliary Drainage Duct in Diagnosing
Residual Common Bile Duct Stones. Biomed Res Int. 2020 ; 2020: 3281241. ” reported from
same institution and co-responding author (Dr. ShaoShan Tang). They studied large number of
patients compared to previous report, however evaluating points are almost same (common bile
duct length and diameter, imaging degree of common bile duct, detection of residual stones, with
or without ENBD saline irrigation). Thus, authors should re-write the contents of this article.
For example, simply, compare the detection rate of residual stones by three different methods
(balloon occluded ERC, US, and US with ENBD) and analyze the factor of false positive and
negative etc. There are some limitations and statistically questionable points. I would like to
comment as following.
Major
1. As mention above, the authors must analyze the data and emphasize the differences from the
previous report.
2. Abstract. Results are difficult to understand. “By occlusion cholangiogram, remnant stones
were suspected in 31 (10.3%) patients, and 26 (83.8%) were verified as true positives (sensitivity,
50.9%; specificity, 98.1%). Routine US studies proved suspicious in 13 (4.3%) patients, and
12 (92.3%) were verified as true positives (sensitivity, 23.5%; specificity, 99.6%)” Does
the calculation of sensitivities and specificity correct? According to the figure 1 and 2, the
calculation may be different.
3. The author needs to distinguish between stone and debris. I think that debris within 3 days
after treatment is often detected when ML was used for stone removal, and existence of debris
immediately after treatment will be discharged without any clinical problems. Could you analyze
the data excluding debris at the CBD?
4. It isn’t a “Novel imaging”. Authors have been described this technique previously.
Title: Title # Endoscopic nasobiliary drainage-based saline-injection ultrasound: an  imaging
technique for remnant stone detection after retrograde cholangiopancreatography
Version: 2 Date: 24 Aug 2021
Reviewer's report:
Thank you for opportunity of review this article, the tile of “Endoscopic nasobiliary drainage-
based saline-injection ultrasound: a novel imaging technique for remnant stone detection after
retrograde cholangiopancreatography”. Authors described the usefulness of US examination
using ENBD tube saline injection, and the detection rate of residual stones are significantly
increased compared to US alone. Similar article “The Value of Contrast-Enhanced Ultrasound-
Guided Contrast Injection via the Endoscopic Nasobiliary Drainage Duct in Diagnosing
Residual Common Bile Duct Stones. Biomed Res Int. 2020 ; 2020: 3281241. ” reported from
same institution and co-responding author (Dr. ShaoShan Tang). They studied large number of
patients compared to previous report, however evaluating points are almost same (common bile
duct length and diameter, imaging degree of common bile duct, detection of residual stones, with
or without ENBD saline irrigation). Thus, authors should re-write the contents of this article.
For example, simply, compare the detection rate of residual stones by three different methods
(balloon occluded ERC, US, and US with ENBD) and analyze the factor of false positive and
negative etc. There are some limitations and statistically questionable points. I would like to
comment as following.
Major
1. As mention above, the authors must analyze the data and emphasize the differences from the
previous report.
2. Abstract. Results are difficult to understand. “By occlusion cholangiogram, remnant stones
were suspected in 31 (10.3%) patients, and 26 (83.8%) were verified as true positives (sensitivity,
50.9%; specificity, 98.1%). Routine US studies proved suspicious in 13 (4.3%) patients, and
12 (92.3%) were verified as true positives (sensitivity, 23.5%; specificity, 99.6%)” Does
the calculation of sensitivities and specificity correct? According to the figure 1 and 2, the
calculation may be different.
3. The author needs to distinguish between stone and debris. I think that debris within 3 days
after treatment is often detected when ML was used for stone removal, and existence of debris
immediately after treatment will be discharged without any clinical problems. Could you analyze
the data excluding debris at the CBD?
4. It isn’t a “Novel imaging”. Authors have been described this technique previously.
Please review this paper.
user
Title: Title # Endoscopic nasobiliary drainage-based saline-injection ultrasound: an  imaging
technique for remnant stone detection after retrograde cholangiopancreatography
Version: 2 Date: 24 Aug 2021
Reviewer's report:
Thank you for opportunity of review this article, the tile of “Endoscopic nasobiliary drainage-
based saline-injection ultrasound: a novel imaging technique for remnant stone detection after
retrograde cholangiopancreatography”. Authors described the usefulness of US examination
using ENBD tube saline injection, and the detection rate of residual stones are significantly
increased compared to US alone. Similar article “The Value of Contrast-Enhanced Ultrasound-
Guided Contrast Injection via the Endoscopic Nasobiliary Drainage Duct in Diagnosing
Residual Common Bile Duct Stones. Biomed Res Int. 2020 ; 2020: 3281241. ” reported from
same institution and co-responding author (Dr. ShaoShan Tang). They studied large number of
patients compared to previous report, however evaluating points are almost same (common bile
duct length and diameter, imaging degree of common bile duct, detection of residual stones, with
or without ENBD saline irrigation). Thus, authors should re-write the contents of this article.
For example, simply, compare the detection rate of residual stones by three different methods
(balloon occluded ERC, US, and US with ENBD) and analyze the factor of false positive and
negative etc. There are some limitations and statistically questionable points. I would like to
comment as following.
Major
1. As mention above, the authors must analyze the data and emphasize the differences from the
previous report.
2. Abstract. Results are difficult to understand. “By occlusion cholangiogram, remnant stones
were suspected in 31 (10.3%) patients, and 26 (83.8%) were verified as true positives (sensitivity,
50.9%; specificity, 98.1%). Routine US studies proved suspicious in 13 (4.3%) patients, and
12 (92.3%) were verified as true positives (sensitivity, 23.5%; specificity, 99.6%)” Does
the calculation of sensitivities and specificity correct? According to the figure 1 and 2, the
calculation may be different.
3. The author needs to distinguish between stone and debris. I think that debris within 3 days
after treatment is often detected when ML was used for stone removal, and existence of debris
immediately after treatment will be discharged without any clinical problems. Could you analyze
the data excluding debris at the CBD?
4. It isn’t a “Novel imaging”. Authors have been described this technique previously.
assistant