Determining the patency of biliary tracts in dogs with gallbladder mucocele using near-infrared cholangiography with indocyanine green

Su-Hyeon Kim; Sungin Lee

doi:10.1371/journal.pone.0300395

. 2024 May 22;19(5):e0300395. doi: 10.1371/journal.pone.0300395

Determining the patency of biliary tracts in dogs with gallbladder mucocele using near-infrared cholangiography with indocyanine green

Su-Hyeon Kim ^1,², Sungin Lee ^1,^*

Editor: Wenguo Cui³

PMCID: PMC11111041 PMID: 38776340

Abstract

Cholecystectomy is indicated for gallbladder mucoceles (GBM). Evaluating the patency of the biliary duct and precise biliary tree visualization is crucial for reducing the risk of compromised bile flow after surgery. Therefore, intraoperative cholangiography (IOC) is recommended during cholecystectomy to prevent biliary tract injury. Although indocyanine green (ICG) cholangiography has been extensively reported in human medicine, only one study has been conducted in veterinary medicine. Therefore, this study aimed to demonstrate the use of ICG for IOC to identify fluorescent biliary tract images and determine the patency of the common bile duct during cholecystectomy in dogs. This study comprised 27 dogs, consisting of 17 with gallbladder mucoceles (GBM) and 10 controls, specifically including dogs that had undergone elective cholecystectomy for GBM. ICG injection (0.25 mg/kg) was administered intravenously at least 45 minutes before surgery. During the operation, fluorescent images from cholangiography were displayed on the monitor and obtained in black-and-white mode for the comparison of fluorescence intensity (FI). The FI values of the gallbladders (GBs) and common bile duct (CBD) were measured using FI analyzing software (MGViewer V1.1.1, MetapleBio Inc.). The results demonstrated successful CBD patency identification in all cases. Mobile GBM showed partial gallbladder visibility, whereas immobile GBM showed limited visibility. Additionally, insights into the adequate visualization of the remaining extrahepatic biliary tree anatomy were provided, extending beyond the assessment of CBD patency and gallbladder intensity. Our study demonstrates the potential of fluorescent IOC using intravenous injection of ICG for assessing the patency of the cystic duct and common bile duct during cholecystectomy in patients with GBM, eliminating the need for surgical catheterization and flushing of the biliary ducts. Further research is warranted to investigate and validate the broader applicability of ICG cholangiography in veterinary medicine.

Introduction

Gallbladder mucocele (GBM), characterized by the accumulation of excess mucin and bile in the gallbladder (GB), can cause partial or complete extrahepatic biliary obstruction (EHBO) by extending bile-laden mucus into the cystic, hepatic, and common bile ducts (CBDs) [1]. As a result of biliary tract outflow obstruction and progressive GB distension, pressure necrosis of the GB or bile duct may result in rupture and subsequent bile peritonitis, which can be life-threatening. Cholecystectomy is indicated for GBM treatment [2]. It is crucial to confirm the patency of the CBD and obtain adequate visualization of the anatomy of the extrahepatic biliary tree to ensure safe dissection and reduce the risk of compromised bile flow after surgery resulting from residual bile plugs or gallstones. Generally, catheterization and flushing of the biliary ducts, accomplished by normograde or retrograde techniques, are proposed to ensure patency [3]. However, intraoperative catheterization remains controversial because of the risk of iatrogenic damage to the biliary tract and prolonged surgical time [4, 5].

Initially introduced by Mirizzi in 1937, intraoperative cholangiography (IOC) is recommended during cholecystectomy to prevent biliary tract injuries [6]. In the field of human medicine, intraoperative near-infrared (NIR) fluorescent cholangiography using a real-time imaging technique with intravenous administration of indocyanine green (ICG) has been widely used to assess fluorescent images of the biliary tract, enabling real-time assessment of fluorescent images of the biliary tract, and reducing biliary tract injury [7]. NIR fluorescence with a wavelength of 750–900 nm is not visible to the human eye [8]. Its novel, less invasive, and non-radioactive technique can enable the real-time assessment of fluorescent images of the biliary tract without altering the surgical field. Using IOC, surgeons can obtain accurate information on bile duct patency. Establishing IOC as a routine procedure may encourage surgeons to make better prognoses during cholecystectomy.

Although ICG cholangiography has been extensively reported in human medicine, only one study that conducted cholangiography in normal dogs has been reported in veterinary literature [9]. On the other hand, in this study, we attempted to investigate the cases of dogs with GBM. We hypothesized that IV injection of ICG could provide fluorescent images of the biliary tract and determine the patency of the CBD without necessitating surgical catheterization or flushing of the ducts. The objective of this study was to describe a technique for performing fluorescent IOC using IV injection of ICG to provide fluorescent images of the biliary tracts and to determine the patency of the CBD in client-owned dogs with normal GBs and those with GBM.

Materials and methods

Study population and preoperative assessment

Client-owned dogs were prospectively recruited for the study from February 202l until August 2023. The subjects comprised 27 client-owned dogs with GBM who underwent cholecystectomy (n = 17). A total of 10 control patients with normal GBs undergoing open abdominal surgery were also included. All GBs in the control group were determined to be normal based on abdominal ultrasound and blood analysis.

Dogs with GBM were diagnosed using abdominal ultrasound at the Department of Veterinary Radiology, College of Veterinary Medicine, Chungbuk National University. GBM was confirmed by histopathological assessment after surgery. Only dogs that had undergone elective cholecystectomy for GBM were included in the study. Dogs that were defined as non-elective, if there was evidence of clinical signs attributed to hepatobiliary disease with associated hyperbilirubinemia or if there was evidence of ultrasonographic findings associated with reactive changes, impending rupture, rupture of the GBM, or physical obstruction of the CBD were excluded from this study. Dogs with none of the above criteria or an incidental finding of GBM were deemed elective and enrolled in the study. The 17 dogs with GBM that participated in this study were divided into two groups depending on the mucocele stage: an immobile GBM group (n = 11) and a mobile GBM group (n = 6) (Fig 1). The GBs were classified into three groups: (i) normal gallbladder; (ii) mobile GBM; and (iii) immobile GBM. The diagnosis of GBM depends on imaging studies, blood test results, and clinical signs, such as anorexia, vomiting, and lethargy [10]. Abdominal ultrasonography is one of the most useful diagnostic tools for evaluating GBM [11]. On abdominal ultrasonography, immobile and echogenic bile with a finely striated or stellated pattern is typically observed within the GBM [12]. This distinguishes it from GB sludge, which exhibits bile movement independent of gravity [13].

All dogs underwent physical and imaging examinations, including radiography and abdominal ultrasonography, complete blood counts, and serum biochemical analysis. The biochemical panel included ALP, ALT, GGT, AST, cholesterol, bilirubin, and triglyceride levels, which are associated with hepatobiliary disease. All the samples were analyzed using a Hitachi 7180 automated biochemical analyzer (Hitachi, Tokyo, Japan) equipped with commercial kits (JW Pharmaceutical, Seoul, Republic of Korea).

Informed consent

All patients were client-owned dogs that underwent abdominal surgery at the Department of Veterinary Surgery, Veterinary Medical Teaching Hospital of Chungbuk National University. Written informed consent was obtained from each owner, and all procedures were approved by the Chungbuk National University Institutional Animal Care and Use Committee (CBNUA-2190-23-02).

Administration of ICG

As a source of fluorescence, 0.25 mg/kg ICG (25 mg of ICG, Cellbion Green, Cellbion Co., Ltd., Seoul, South Korea) was injected intravenously at least 45 min before surgery, up to a maximum of 2 hours. About 25 mg vial was dissolved in 10 mL of sterile water, and 1 mL of the dissolved solution was further diluted with an additional 9 mL of sterile water to create a 0.25/mL solution immediately before injection. ICG was administered only to patients without renal failure or a history of adverse reactions to the iodine solution.

Fluorescent imaging system

Intraoperative ICG display was performed using an intraoperative NIR fluorescence-guided imaging system (Metaple Bio, Seoul, South Korea). It comprises a control unit and a ‘NIR’ light source. The NIR light source produces a wavelength of 802.5 nm, and this imaging system detects infrared light above the bile duct. The distance between the laser output and surgical site, which was the working distance in the fluorescence imaging system, was 40 cm. During the operation, fluorescent images of the cholangiography were displayed on the monitor and obtained in black-and-white mode to compare the fluorescence intensity (FI). FI values of the GBs and CBD were measured using FI analyzing software (MGViewer V1.1.1, MetapleBio Inc.) (Fig 2). Bile duct patency was determined by comparing FI values. In the control group, values for the gallbladder (GB) and common bile duct (CBD) were established. When FI values of the CBD in GBM patients closely resembled those in the control group, CBD patency was considered confirmed. This criterion ensured a thorough evaluation of bile duct patency while minimizing unnecessary interventions. Cholecystectomy was only performed for GBM dogs and those with GB sludge who underwent liver lobectomy for visualization.

Monitoring

After administration of ICG, the patients were closely monitored for any signs of adverse reactions involving the cardiac, or respiratory (anaphylaxis) [14]. Monitoring included continuous observation for changes in heart rate, respiratory rate, mean arterial pressure, and oxygen saturation during the anesthesia. After the patients recovered from the anesthesia, close monitoring of physical examination, heart rate, respiratory rate, mean arterial pressure and oxygen saturation were continuously conducted using monitoring devices. Additionally, blood analysis and hepatic ultrasonography were performed within one week following surgery, with follow-up examinations conducted one week, two weeks, and one month postoperatively to assess for any delayed adverse effects or complications.

Statistical analysis

Statistical analyses were performed using the SPSS statistical software package, version 24.0. (SPSS Inc., Chicago, IL, USA). The Shapiro–Wilk method was used to evaluate whether the obtained data were normally distributed. An independent t-test was used to analyze the differences in age and total cholesterol between the control group with normal GB and the GBM group. The Mann–Whitney U-test was performed to analyze differences in body weight and biochemical characteristics, such as triglyceride, ALT, AST, ALP, GGT, and total bilirubin levels, between the control group with normal GB and the GBM group. Data were presented as means and standard deviations. Welch’s ANOVA was performed to analyze the differences in FI among the following groups: controls (Normal GB), dogs with immobile GBM, and dogs with mobile GBM. If a significant difference was detected, the Games–Howell test was performed for post-hoc comparisons. Data were presented as means and standard deviations. Statistical significance was set at P-value<0.05.

Results

Patients’ characteristics

Basic information on the 10 dogs with normal GBs (n = 10) and 17 dogs with GBM (n = 17) are summarized in Table 1. The median age of the dogs with GBM was 12 years, which was higher than that of control dogs with normal GB (9 years old) (p = 0.002). Total cholesterol, triglyceride, and ALP levels were higher in dogs with GBM than in dogs with normal GB (p = 0.042, p = 0.003, and p = 0.007, respectively). Body weight and ALT, AST, GGT, and total bilirubin levels did not significantly differ between the groups.

Table 1. Comparison of age, sex, breed, body weight (BW), and biochemical characteristics between dogs with normal gallbladder (controls) and dogs with gallbladder mucocele.

	Dogs with normal GB (n = 10)	Dogs with GBM (n = 17)	P
Age (years)	9.00 (2.25)	12.00 (2.00)	0.002	0.002
0.002
Sex (n)	Entire female (4)	Entire female (8)
	Entire male (2)	Entire male (2)
	Spayed female (4)	Spayed female (6)
	Castrated male (0)	Castrated male (1)
Breed (n)	Poodle (3)	Maltese (4)
	Maltese (2)	Cocker-Spaniel (3)
	Mixed breed (1)	Poodle (2)
	Shih-Tzu (1)	Shih-Tzu (2)
	Pomeranian (1)	Spitz (2)
	Chihuahua (1)	Pomeranian (1)
	Cocker-Spaniel (1)	Chihuahua (1)
		Golden Retriever (1)
		Yorkshire Terrier (1)
BW (kg)	5.41 (3.60)	5.17 (5.90)	0.530
Total cholesterol (mg/dL)	194.5 (68.75)	234 (109) ^*	0.042
Triglycerides (mg/dL)	53 (16.75)	121 (49.00) ^*	0.003
ALT (IU/L)	43 (18.00)	79 (83.00)	0.063
AST (IU/L)	22 (14.25)	23 (12.00)	0.724
ALP (IU/L)	32 (26.25)	379 (528.00) ^*	0.007
GGT (IU/L)	5 (2.75)	6 (10.00)	0.173
T.bil (mg/dL)	0.025 (0.03)	0.02 (0.05)	0.818

Open in a new tab

Data are expressed as the median with the interquartile range (presented in brackets).

n, Number of patients; BW, bodyweight; ALT, alanine transaminase; AST, aspartate transaminase; ALP, alkaline phosphatase; GGT, gamma-glutamyl transferase; T.bil, Total bilirubin.

Reference ranges are as follows: Total cholesterol [112–312]; triglycerides [21–133]; ALT [21–102]; AST [23–66]; ALP [29–97]; GGT [1–10]; and T.bil [0.1–0.5].

*p<0.05

IOC using ICG fluorescence imaging systems

The results of fluorescence imaging are presented in Fig 3. The results of fluorescence imaging are presented in Fig 3. The fluorescent cholangiography using ICG identified the CBD in all 27 patients (n = 27). In dogs with normal GBs (n = 10), intraoperative fluorescent cholangiography using a NIR fluorescent imaging system also detected the GB, cystic ducts, and hepatic ducts. The entire length of the cystic and CBDs could be visualized, as well as the junction of the cystic and CBDs (Fig 3A). Interestingly, the GB was partially visualized in dogs with mobile GBM (n = 6). The part where the mucocele was attached to the ventral side of the GB was not detected using the NIR fluorescence camera, whereas the other part was visualized (Fig 3B). Mucoceles were not detected on ICG fluorescence cholangiography (Fig 3B and 3C). In dogs with immobile GBM (n = 11), the entire GB could not be visualized with ICG fluorescence. The entire length of the cystic duct was also not visualized in a group of immobile GBM (Fig 3C). Bile duct patency was determined by comparing FI values. FI values of CBD in the GBM group showed similar FI values in the control group, there, no flushing was performed in GBM groups in which CBD patency was confirmed through FI value comparison. Fluorescence of the CBD persisted until the closure of the abdomen in both the control and the GBM groups. Moreover, ICG cholangiography revealed the passage into the duodenum in both the control and the GBM groups (Fig 4). ICG fluorescence was also readily visible in the liver.

Fig 4 — Image of intraoperative ICG cholangiography in a dog. The yellow arrow indicates ICG observed in the passage into the duodenum.

All patients successfully recovered from the anesthesia. None of the dogs showed adverse reactions to ICG. Postoperative follow-up was conducted on all patients, including those with immobile GBM, for several weeks after surgery. During these follow-up periods, clinical assessments, ultrasonography, and blood tests were performed for monitoring. All patients showed favorable outcomes, with no complications observed up to a 6-month follow-up period.

Analysis of FI in control dogs with normal GB, dogs with mobile GBM, and dogs with immobile GBM

Dogs with GBM were divided into two groups: dogs with mobile GBM and those with immobile GBM. The FI of the GB in dogs with a normal GB (Average 15569-pixel values) was significantly higher than that of dogs with GBM of both mobile (Average 4494-pixel values) and immobile (Average 735-pixel values) (P<0.001 and P<0.001, respectively). Furthermore, in dogs with GBM, the FI was higher in the mobile GBM groups (Average 4494-pixel values) than in the immobile group (Average 735-pixel values) (P<0.001) (Fig 5). However, the FI of the CBD did not significantly differ between the group with normal GB and groups with GBM (P = 0.079) (Fig 6).

Fig 5 — Comparison of the FI of the gallbladder (GB) among the following groups: controls with normal GB (n = 10), dogs with mobile GBM (n = 6), and dogs with immobile GBM (n = 11). The fluorescence intensity of the gallbladder (GB) was significantly higher in dogs with normal gallbladders than that of dogs with GBM. FI was higher in dogs with mobile GBM than in immobile GBM dogs. Columns indicate mean values, and vertical error bars represent standard deviations. *P<0.001 between groups.

Fig 6 — The fluorescence intensity of the common bile duct did not significantly differ between dogs with a normal gallbladder (GB), mobile GBM, or immobile GBM. Comparison of fluorescence intensity of the CBD among the following groups: Controls with normal GB (n = 10), dogs with mobile GBM (n = 6), and dogs with immobile GBM (n = 11). Columns indicate mean values, and vertical error bars represent standard deviations. *P<0.001 between groups.

Discussion

In this study, NIR cholangiography was successfully performed in all 27 client-owned dogs, revealing the patency of the CBD with minimal invasiveness. The CBD was visualized using an NIR camera in all patients until the end of the surgery. Furthermore, NIR cholangiography using ICG made it possible to delineate the structure of the biliary trees, including the passage of fluorescence into the duodenum. Fluorescent images revealed filling defects in the GBs of 17 dogs with GBM. We believe that extrahepatic biliary obstruction may be demonstrated using this technique.

Hyperlipidemia, characterized by elevated serum levels of total cholesterol, triglycerides, or both, is related to the formation of GBM [15]. In the present study, blood concentrations of total cholesterol and triglycerides were higher in dogs in the GBM group than in controls with healthy GBs. 11 dogs with immobile GBM showed striated, stellate, or mixed patterns, and 6 dogs with mobile GBM partially showed a striated or stellate pattern with biliary sludge. Elective cholecystectomy is strongly recommended for patients with GBM. Studies have consistently demonstrated that dogs undergoing elective surgery exhibit lower mortality rates compared to those undergoing nonelective procedures. Performing elective cholecystectomy before the onset of clinical signs significantly increases the chances of a successful outcome [2]. In veterinary medicine, there has been ongoing discussion regarding the confirmation of biliary tract patency even in elective surgeries [16]. Therefore, IOC has been regarded as a potential technique enabling the assessment of patency and visualization of biliary trees [6].

IOC has been recommended to assess biliary trees in humans [17]. Bile duct injury due to misinterpretation of biliary anatomy constitutes a serious complication of cholecystectomy [18]. Over the past few years, fluorescence-guided surgery using ICG during cholecystectomy has emerged as a new technology that allows for real-time enhanced visualization and identification of extrahepatic biliary structures without the use of radiation [19]. During IV injection, ICG rapidly binds to intravascular plasma proteins, which are then cleared by the liver, specifically taken up by hepatocytes, and excreted into the bile. Therefore, protein bound ICG by NIR light causes fluorescence and visualizes the biliary trees [20]. As a result, ICG fluorescence cholangiography facilitates the accurate identification of biliary tracts and high-risk areas that should be monitored before resection and allows for the localization of important landmarks. One of the advantages of fluorescent IOC is its ability to provide a reliable roadmap of the bile duct anatomy and identify the CBD before dissection. This can reduce the chances of iatrogenic injury and assist surgeons in selecting the best location for dissection [21]. In addition, with fluorescent cholangiography, the cystic duct can be identified without the need to dissect Calot’s triangle or insert a transcystic tube for the injection of contrast material, procedures which have a risk of causing bile duct damage [22]. Finally, compared with radiographic cholangiography, fluorescent cholangiography with IV injection of ICG offers safety and is devoid of radiation exposure. It is a convenient procedure that does not require space-occupying devices such as a C-arm or assistance in performing the device [17].

The significance of IOC in veterinary medicine has been acknowledged [23–25]. While bile duct flushing during cholecystectomy removes mucus and inflammatory debris from the CBD [26], it may not perfectly rule out the possibility of partial obstruction, stricture, or other debris [23]. In contrast, cholangiography offers a precise assessment of the patency of the CBD and concurrently reduces the risk of bile duct injury [27]. In one study, CT cholangiography was reported in dogs, underscoring the necessity of this imaging system for assessing EHBO [24]. Other studies have demonstrated IOC using the C-arm in the veterinary field, highlighting its advantages over CT in terms of accuracy and real-time imaging [23, 25]. However, radiological imaging of the biliary tract may only be used selectively because the process takes time, involves radiation exposure, and needs some additional equipment and manpower for the procedure [17]. Hence, in veterinary medicine, there is a need for NIR fluorescence cholangiography, which is promising for the facile intraoperative identification of biliary anatomy. A recent study favorably mentioned the implementation of ICG cholangiography in eight healthy dogs [9]. ICG cholangiography with an IV injection of ICG was successfully performed in all eight dogs, providing guidelines for NIRF cholangiography in clinically normal dogs.

Visualization of the biliary tract is crucial during cholecystectomy, particularly in canine patients with GBM, where confirmation of CBD patency is crucial [26]. Catheterization and flushing of the CBD before cystic duct ligation have been proposed to reduce the risk of postoperative compromised bile flow from choleliths or residual bile plugs and to ensure CBD patency [3, 28, 29]. Nevertheless, the need for intraoperative catheterization during cholecystectomy is still controversial [4]. The routine flushing of the CBD in patients with GBM may not be beneficial and may even lead to associated morbidity. Retrograde catheterization necessitates duodenotomy to access the major duodenal papilla (MDP), which can lead to prolonged surgical duration, increased anesthesia time, and a higher risk of complications such as intestinal adhesions and perforations. Furthermore, this procedure may adversely affect gastrointestinal motility. Reported complications related to retrograde catheterization include gallbladder necrosis, hepatic abscessation, and duodenal dehiscence or perforation [3]. Acute pancreatitis carries a high mortality rate in veterinary medicine, emphasizing the clinical significance of this complication [30]. Previous studies have shown that CBD catheterization, regardless of the approach, can increase surgical time without significant postoperative bilirubin level improvement [31, 32]. This suggests that CBD flushing may lead to the reflux of biliary secretions into the pancreatic duct, potentially causing pancreatitis, or result in trauma to the major duodenal papilla, leading to inflammation and temporary occlusion of the pancreatic duct orifice. Given these risks, it is crucial to consider alternative techniques. In NIR fluorescence IOC, proposed in this study, can ensure the patency of the CBD without the risk of catheterization and flushing. In this study, all 27 dogs with confirmed CBD patency exhibited FI similar to that of the CBD. However, when comparing the CBD in the GB, the GBM group showed a lower FI of the GB than the normal group, indicating that the mucocele did not manifest under ICG. This indicates that NIR fluorescence IOC facilitates the visualization of the biliary tract and enables the detection of mucocele presence, thereby confirming the patency of the CBD. This approach of using IOC with an IV injection of ICG is a novel technique that offers a less invasive approach for assessing biliary tract patency and visualization and enhances postoperative outcomes.

In this study, ICG was administered intravenously at 0.25 mg/kg at least 45 minutes before the surgery. The timing and dosages of ICG injection were decided because they showed effective intraoperative identification of biliary anatomy practically and safely in a human study [33]. After IV injection, more than 95% of ICG was cleared by hepatocytes and excreted into the bile within 15 min [5]. The FI of CBD peaks within 2–8 h depending on the dosage and species, and then gradually decreases [8, 34]. In one study, doses ranging from 0.05 to 0.25 mg/kg were used for cholangiography in healthy dogs [9]. Ultimately, when comparing our results, the dosage of 0.25 mg/kg itself is considered appropriate for evaluating patency. However, since only healthy dogs were compared, additional research is needed to determine the results based on dosage depending on pathological conditions. Therefore, further studies are warranted to determine optimal dosages based on pathological conditions, especially in dogs with GBM. In this study, the FI analyzing software (MGViewer V1.1.1, MetapleBio Inc.) was used to measure the absolute FI of the CBD in different cases. Previous studies have reported that ICG administration is safe, and well tolerated [35, 36]. Approximately 0.003% of anaphylactic reactions occur at doses higher than 0.5 mg/kg [37]. Because 0.25 mg/kg was intravenously injected for cholangiography in this study, the risk was thought to be still relatively low. However, it is important to note that while the dogs in this study did not experience any side effects from ICG, further research is necessary, as there have been no safety studies or recommended dosages reported specifically for dogs.

This study had a few limitations. First, the sample size of GB mucocele patients was small, limiting the generalizability of the findings to a broader population. Therefore, a study design with a larger sample size is required to provide more precise and reliable results and confirm our findings. Second, there were some limitations in assessing the optimal timing and dosage of ICG administration during fluorescent IOC, which could affect the accuracy and effectiveness of the technique. Further well-designed studies are warranted to address these limitations and provide more robust evidence on the optimal timing and dose of ICG administration during fluorescent intraoperative cholangiography.

Conclusion

In conclusion, this study demonstrates the application of NIR fluorescence IOC with IV injection of ICG in dogs. The cholangiography with ICG effectively visualized the biliary tract with minimal invasiveness, allowing for a comprehensive assessment of the CBD patency and delineation of biliary tree structures during cholecystectomy. While the study highlights its potential in canine patients with GBM, it is important to acknowledge certain limitations, particularly related to the representativeness of the study population and the necessity of catheterization in cases of obstruction. Future studies with larger sample sizes and refined methodologies to explore the optimal timing and dosage of ICG administration are required to validate the findings of this study and to further elucidate the clinical utility of this innovative technique in veterinary medicine.

Supporting information

S1 Fig. 1 fluorescence intensity of gallbladder and common bile duct of all patients.

(PDF)

pone.0300395.s001.pdf^{(27.9KB, pdf)}

Data Availability

All relevant data are within the manuscript and its Supporting Information files.

Funding Statement

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (RS-2023-00253736) and also supported by the Basic Research Lab Program (2022R1A4A1025557) through the National Research Foundation (NRF) of Korea, funded by the Ministry of Science and ICT.

References

1.Aguirre AL, Center SA, Randolph JF, Yeager AE, Keegan AM, Harvey HJ, et al. Gallbladder disease in Shetland Sheepdogs: 38 cases (1995–2005). J Am Vet Med Assoc. 2007;231(1): 79–88. doi: 10.2460/javma.231.1.79 [DOI] [PubMed] [Google Scholar]
2.Friesen SL, Upchurch DA, Hollenbeck DL, Roush JK. Clinical findings for dogs undergoing elective and nonelective cholecystectomies for gall bladder mucoceles. J Small Anim Pract. 2021;62(7): 547–53. doi: 10.1111/jsap.13312 [DOI] [PubMed] [Google Scholar]
3.Putterman AB, Selmic LE, Kindra C, Duffy DJ, Risselada M, Phillips H. Influence of normograde versus retrograde catheterization of bile ducts in dogs treated for gallbladder mucocele. Vet Surg. 2021;50(4): 784–93. doi: 10.1111/vsu.13632 [DOI] [PubMed] [Google Scholar]
4.Rossanese M, Williams P, Tomlinson A, Cinti F. Long-Term Outcome after Cholecystectomy without Common Bile Duct Catheterization and Flushing in Dogs. Animals (Basel). 2022;12(16). doi: 10.3390/ani12162112 [DOI] [PMC free article] [PubMed] [Google Scholar]
5.Boni L, David G, Mangano A, Dionigi G, Rausei S, Spampatti S, et al. Clinical applications of indocyanine green (ICG) enhanced fluorescence in laparoscopic surgery. Surg Endosc. 2015;29(7): 2046–55. doi: 10.1007/s00464-014-3895-x [DOI] [PMC free article] [PubMed] [Google Scholar]
6.Aoki T, Murakami M, Yasuda D, Shimizu Y, Kusano T, Matsuda K, et al. Intraoperative fluorescent imaging using indocyanine green for liver mapping and cholangiography. J Hepatobiliary Pancreat Sci. 2010;17(5): 590–4. doi: 10.1007/s00534-009-0197-0 [DOI] [PubMed] [Google Scholar]
7.Quaresima S, Balla A, Palmieri L, Seitaj A, Fingerhut A, Ursi P, et al. Routine near infra-red indocyanine green fluorescent cholangiography versus intraoperative cholangiography during laparoscopic cholecystectomy: a case-matched comparison. Surg Endosc. 2020;34(5): 1959–67. doi: 10.1007/s00464-019-06970-0 [DOI] [PubMed] [Google Scholar]
8.Verbeek FP, Schaafsma BE, Tummers QR, van der Vorst JR, van der Made WJ, Baeten CI, et al. Optimization of near-infrared fluorescence cholangiography for open and laparoscopic surgery. Surg Endosc. 2014;28(4): 1076–82. doi: 10.1007/s00464-013-3305-9 [DOI] [PMC free article] [PubMed] [Google Scholar]
9.Larose PC, Brisson BA, Sanchez A, Monteith G, Singh A, Zhang M. Near-infrared fluorescence cholangiography in dogs: A pilot study. Vet Surg. 2023. doi: 10.1111/vsu.14007 [DOI] [PubMed] [Google Scholar]
10.Crews LJ, Feeney DA, Jessen CR, Rose ND, Matise I. Clinical, ultrasonographic, and laboratory findings associated with gallbladder disease and rupture in dogs: 45 cases (1997–2007). J Am Vet Med Assoc. 2009;234(3): 359–66. doi: 10.2460/javma.234.3.359 [DOI] [PubMed] [Google Scholar]
11.Pike FS, Berg J, King NW, Penninck DG, Webster CR. Gallbladder mucocele in dogs: 30 cases (2000–2002). J Am Vet Med Assoc. 2004;224(10): 1615–22. doi: 10.2460/javma.2004.224.1615 [DOI] [PubMed] [Google Scholar]
12.Uno T, Okamoto K, Onaka T, Fujita K, Yamamura H, Sakai T. Correlation between ultrasonographic imaging of the gallbladder and gallbladder content in eleven cholecystectomised dogs and their prognoses. J Vet Med Sci. 2009;71(10): 1295–300. doi: 10.1292/jvms.001295 [DOI] [PubMed] [Google Scholar]
13.Walter R, Dunn ME, d’Anjou MA, Lécuyer M. Nonsurgical resolution of gallbladder mucocele in two dogs. J Am Vet Med Assoc. 2008;232(11): 1688–93. doi: 10.2460/javma.232.11.1688 [DOI] [PubMed] [Google Scholar]
14.HOPE-ROSS Monique, et al. Adverse reactions due to indocyanine green. Ophthalmology, 1994;101(3): 529–533. doi: 10.1016/s0161-6420(94)31303-0 [DOI] [PubMed] [Google Scholar]
15.Lee S, Kweon OK, Kim WH. Increased Leptin and Leptin Receptor Expression in Dogs With Gallbladder Mucocele. J Vet Intern Med. 2017;31(1): 36–42. doi: 10.1111/jvim.14612 [DOI] [PMC free article] [PubMed] [Google Scholar]
16.Youn G, Waschak MJ, Kunkel KAR, Gerard PD. Outcome of elective cholecystectomy for the treatment of gallbladder disease in dogs. J Am Vet Med Assoc. 2018;252(8): 970–5. doi: 10.2460/javma.252.8.970 [DOI] [PubMed] [Google Scholar]
17.Ishizawa T, Tamura S, Masuda K, Aoki T, Hasegawa K, Imamura H, et al. Intraoperative fluorescent cholangiography using indocyanine green: a biliary road map for safe surgery. J Am Coll Surg. 2009;208(1): e1–4. doi: 10.1016/j.jamcollsurg.2008.09.024 [DOI] [PubMed] [Google Scholar]
18.Schols RM, Bouvy ND, Masclee AA, van Dam RM, Dejong CH, Stassen LP. Fluorescence cholangiography during laparoscopic cholecystectomy: a feasibility study on early biliary tract delineation. Surg Endosc. 2013;27(5): 1530–6. doi: 10.1007/s00464-012-2635-3 [DOI] [PubMed] [Google Scholar]
19.Cassinotti E, Al-Taher M, Antoniou SA, Arezzo A, Baldari L, Boni L, et al. European Association for Endoscopic Surgery (EAES) consensus on Indocyanine Green (ICG) fluorescence-guided surgery. Surg Endosc. 2023;37(3): 1629–48. doi: 10.1007/s00464-023-09928-5 [DOI] [PMC free article] [PubMed] [Google Scholar]
20.Dip F, LoMenzo E, Sarotto L, Phillips E, Todeschini H, Nahmod M, et al. Randomized Trial of Near-infrared Incisionless Fluorescent Cholangiography. Ann Surg. 2019;270(6): 992–9. doi: 10.1097/SLA.0000000000003178 [DOI] [PubMed] [Google Scholar]
21.Zroback C, Chow G, Meneghetti A, Warnock G, Meloche M, Chiu CJ, et al. Fluorescent cholangiography in laparoscopic cholecystectomy: the initial Canadian experience. Am J Surg. 2016;211(5): 933–7. doi: 10.1016/j.amjsurg.2016.01.013 [DOI] [PubMed] [Google Scholar]
22.Pesce A, Piccolo G, La Greca G, Puleo S. Utility of fluorescent cholangiography during laparoscopic cholecystectomy: A systematic review. World J Gastroenterol. 2015;21(25): 7877–83. doi: 10.3748/wjg.v21.i25.7877 [DOI] [PMC free article] [PubMed] [Google Scholar]
23.Kanai H, Minamoto T, Nukaya A, Kondo M, Aso T, Fujii A, et al. Intraoperative cholangiography and bile duct flushing in 47 dogs receiving laparoscopic cholecystectomy for benign gallbladder disease: A retrospective analysis. Vet Surg. 2022;51 Suppl 1:O150–o9. doi: 10.1111/vsu.13731 [DOI] [PubMed] [Google Scholar]
24.Hayakawa S, Sato K, Sakai M, Kutara K, Asano K, Watari T. CT cholangiography in dogs with gallbladder mucocoele. Journal of Small Animal Practice. 2018. Aug;59(8): 490–5. doi: 10.1111/jsap.12832 [DOI] [PubMed] [Google Scholar]
25.Kanai H, Hagiwara K, Nukaya A, Kondo M, Aso T. Short-term outcome of laparoscopic cholecystectomy for benign gall bladder diseases in 76 dogs. J Vet Med Sci. 2018;80(11): 1747–53. doi: 10.1292/jvms.18-0266 [DOI] [PMC free article] [PubMed] [Google Scholar]
26.Malek S, Sinclair E, Hosgood G, Moens NM, Baily T, Boston SE. Clinical findings and prognostic factors for dogs undergoing cholecystectomy for gall bladder mucocele. Vet Surg. 2013;42(4): 418–26. doi: 10.1111/j.1532-950X.2012.01072.x [DOI] [PubMed] [Google Scholar]
27.Vlek SL, van Dam DA, Rubinstein SM, de Lange-de Klerk ESM, Schoonmade LJ, Tuynman JB, et al. Biliary tract visualization using near-infrared imaging with indocyanine green during laparoscopic cholecystectomy: results of a systematic review. Surg Endosc. 2017;31(7): 2731–42. doi: 10.1007/s00464-016-5318-7 [DOI] [PMC free article] [PubMed] [Google Scholar]
28.Scott J, Singh A, Mayhew PD, Brad Case J, Runge JJ, Gatineau M, et al. Perioperative Complications and Outcome of Laparoscopic Cholecystectomy in 20 Dogs. Vet Surg. 2016;45(S1): O49–o59. doi: 10.1111/vsu.12534 [DOI] [PubMed] [Google Scholar]
29.Amsellem PM, Seim HB 3rd, MacPhail CM, Bright RM, Twedt DC, Wrigley RH, et al. Long-term survival and risk factors associated with biliary surgery in dogs: 34 cases (1994–2004). J Am Vet Med Assoc. 2006;229(9): 1451–7. doi: 10.2460/javma.229.9.1451 [DOI] [PubMed] [Google Scholar]
30.Fabrès V, Dossin O, Reif C, Campos M, Freiche V, Maurey C, et al. Development and validation of a novel clinical scoring system for short-term prediction of death in dogs with acute pancreatitis. J Vet Intern Med. 2019;33(2): 499–507. doi: 10.1111/jvim.15421 [DOI] [PMC free article] [PubMed] [Google Scholar]
31.Piegols HJ, Hayes GM, Lin S, Singh A, Langlois DK, Duffy DJ. Association between biliary tree manipulation and outcome in dogs undergoing cholecystectomy for gallbladder mucocele: A multi-institutional retrospective study. Vet Surg. 2021;50(4): 767–74. doi: 10.1111/vsu.13542 [DOI] [PubMed] [Google Scholar]
32.Hernon TL, Friend EJ, Chanoit G, Black V, Meakin LB. The effect of flushing of the common bile duct on hepatobiliary markers and short-term outcomes in dogs undergoing cholecystectomy for the management of gall bladder mucocele: A randomized controlled prospective study. Vet Surg. 2023;52(5): 697–703. doi: 10.1111/vsu.13956 [DOI] [PubMed] [Google Scholar]
33.Zarrinpar A, Dutson EP, Mobley C, Busuttil RW, Lewis CE, Tillou A, et al. Intraoperative Laparoscopic Near-Infrared Fluorescence Cholangiography to Facilitate Anatomical Identification: When to Give Indocyanine Green and How Much. Surg Innov. 2016;23(4): 360–5. doi: 10.1177/1553350616637671 [DOI] [PubMed] [Google Scholar]
34.Chen Q, Zhou R, Weng J, Lai Y, Liu H, Kuang J, et al. Extrahepatic biliary tract visualization using near-infrared fluorescence imaging with indocyanine green: optimization of dose and dosing time. Surg Endosc. 2021;35(10): 5573–82. doi: 10.1007/s00464-020-08058-6 [DOI] [PMC free article] [PubMed] [Google Scholar]
35.Ishizawa T, Kaneko J, Inoue Y, Takemura N, Seyama Y, Aoki T, et al. Application of fluorescent cholangiography to single-incision laparoscopic cholecystectomy. Surg Endosc. 2011;25(8): 2631–6. doi: 10.1007/s00464-011-1616-2 [DOI] [PubMed] [Google Scholar]
36.van den Bos J, Wieringa FP, Bouvy ND, Stassen LPS. Optimizing the image of fluorescence cholangiography using ICG: a systematic review and ex vivo experiments. Surg Endosc. 2018;32(12): 4820–32. doi: 10.1007/s00464-018-6233-x [DOI] [PMC free article] [PubMed] [Google Scholar]
37.Speich R, Saesseli B, Hoffmann U, Neftel KA, Reichen J. Anaphylactoid reactions after indocyanine-green administration. Ann Intern Med. 1988;109(4): 345–6. doi: 10.7326/0003-4819-109-4-345_2 [DOI] [PubMed] [Google Scholar]

PLoS One. doi: 10.1371/journal.pone.0300395.r001

Decision Letter 0

Wenguo Cui

18 Jan 2024

PONE-D-23-36283Determining the patency of biliary tracts in dogs with gallbladder mucocele using near-infrared cholangiography with indocyanine greenPLOS ONE

Dear Dr. Lee,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Mar 03 2024 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Wenguo Cui, Ph.D

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Note from Emily Chenette, Editor in Chief of PLOS ONE, and Iain Hrynaszkiewicz, Director of Open Research Solutions at PLOS: Did you know that depositing data in a repository is associated with up to a 25% citation advantage (https://doi.org/10.1371/journal.pone.0230416)? If you’ve not already done so, consider depositing your raw data in a repository to ensure your work is read, appreciated and cited by the largest possible audience. You’ll also earn an Accessible Data icon on your published paper if you deposit your data in any participating repository (https://plos.org/open-science/open-data/#accessible-data).

3. Thank you for stating the following financial disclosure:

"This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (RS-2023-00253736) and also supported by the Basic Research Lab Program (2022R1A4A1025557) through the National Research Foundation (NRF) of Korea, funded by the Ministry of Science and ICT."

Please state what role the funders took in the study. If the funders had no role, please state: "The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."

If this statement is not correct you must amend it as needed.

Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf.

4. Thank you for stating the following in the Acknowledgments Section of your manuscript:

We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form.

Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows:

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

5. Please provide a complete Data Availability Statement in the submission form, ensuring you include all necessary access information or a reason for why you are unable to make your data freely accessible. If your research concerns only data provided within your submission, please write "All data are in the manuscript and/or supporting information files" as your Data Availability Statement.

6. We note that Figure 2 in your submission contain copyrighted images. All PLOS content is published under the Creative Commons Attribution License (CC BY 4.0), which means that the manuscript, images, and Supporting Information files will be freely available online, and any third party is permitted to access, download, copy, distribute, and use these materials in any way, even commercially, with proper attribution. For more information, see our copyright guidelines: http://journals.plos.org/plosone/s/licenses-and-copyright.

We require you to either (1) present written permission from the copyright holder to publish these figures specifically under the CC BY 4.0 license, or (2) remove the figures from your submission:

a. You may seek permission from the original copyright holder of Figure 2 to publish the content specifically under the CC BY 4.0 license.

We recommend that you contact the original copyright holder with the Content Permission Form (http://journals.plos.org/plosone/s/file?id=7c09/content-permission-form.pdf) and the following text:

“I request permission for the open-access journal PLOS ONE to publish XXX under the Creative Commons Attribution License (CCAL) CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). Please be aware that this license allows unrestricted use and distribution, even commercially, by third parties. Please reply and provide explicit written permission to publish XXX under a CC BY license and complete the attached form.”

Please upload the completed Content Permission Form or other proof of granted permissions as an "Other" file with your submission.

In the figure caption of the copyrighted figure, please include the following text: “Reprinted from [ref] under a CC BY license, with permission from [name of publisher], original copyright [original copyright year].”

b. If you are unable to obtain permission from the original copyright holder to publish these figures under the CC BY 4.0 license or if the copyright holder’s requirements are incompatible with the CC BY 4.0 license, please either i) remove the figure or ii) supply a replacement figure that complies with the CC BY 4.0 license. Please check copyright information on all replacement figures and update the figure caption with source information. If applicable, please specify in the figure caption text when a figure is similar but not identical to the original image and is therefore for illustrative purposes only.

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Overview:

This study describes and evaluates an interesting and innovative technic that would be of great help in hepatobiliary surgery.

In general, the manuscript is well written, concise and readable. Some revision would be interesting to

improve description of the material and methods and the results and to make the discussion clearer.

First, the study presents enough data to conclude that this technique permits to visualize the biliary tract in healthy dogs and dogs with GBM but without complete duct obstruction. However, it would also be nice to discuss whether a complete obstruction could limit the visualization of the biliary tract, as suggested from the images obtained from the dog presented in figure 3C. As this situation was not evaluated in this study and in the pilot one in dogs (reference 26), it would be nice to give data from the human literature.

As ICG was observed in the duodenum in all dogs, at least partial patency can be considered and therefore demonstrated with this technic. However, it should be commented and discussed as to whether partial obstruction was still possible. I think that cases with obstruction should have been included to definitively conclude on the use of ICG for the assessment of the patency of the cystic and common bile duct. While it seems judicious to hypothesize (as done lines 243-244) that it could permit to demonstrate obstruction, the data presented here cannot permit to conclude definitively.

The authors stated that this technic can eliminate the need for surgical catherization and flushing. It seems to be an over statement and so need to be mitigated. While it is probably true when the ducts seem patent, catherization would still be required in case of obstruction to remove the obstacle.

Specific comment

Concerning question 3 (Have the authors made all data underlying the findings in their manuscript fully available), I answered no as I understood that the data policy requires that individual data are available such as the fluorescence intensity for each dog (and not a median for the group), etc. If confirmed by the Editors that it is indeed required, I would suggest to give these data as a supporting information.

« The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. »

Abstract:

The abstract is concise and captures some essential features of the manuscript but should be rewritten to be more accurate and to highlight the most relevant information. For example, it should precise that for GBM cases, only elective procedures were included; how fluorescence was assed and quantified, what were the criteria to define bile duct patency. On the contrary, some information is not essential such as “that underwent preoperative assessments, including imaging and biochemical analyses”. Concerning the results, beyond CBD patency and gallbladder intensity, adequate visualization of the anatomy of the remaining extrahepatic biliary tree could be mentioned.

In the view of the limits discussed previously, the conclusion seems overstated and should be mitigated.

Line 30: if only one study has indeed been published (reference 26), “only a few studies” should be modified for “only one”

Line 37: please precise between what significant difference were observed or consider removing the sentence if this information is not crucial.

Introduction

The introduction is appropriate, clearly explain why the subject matters and provide some rational for the study. However, the “few studies” (lines 75-76) should be referenced and commented to justify why the present study was needed.

Materials and methods

This section could be improved by defining more precisely some criterions.

The study seems prospective but it should be clearly stated and the time period for recruitment (line 113) could be mentioned elsewhere than it the “informed consent” paragraph. How the number of cases to be included was determined? It might be more accurate to describe the recruitment criteria in the material and methods section but only give the number of animals effectively included in the results section, except if it was pre-determined.

The criteria to diagnose GBM in general and to differentiate mobile vs immobile case should be define in this section (and not in the discussion). The criteria to define bile duct patency should also be clearly stated.

Could the authors please indicate which side effects were potentially expected and how were they monitored?

Line 119: it would be better to precise also the maximum time period between the injection and the start of the surgery

Statistical analysis: Lines 147-148 it is stated that data were presented as median but it seems that for figures 4 and 5, mean and standard deviation were used. Please, complete the statistical analysis accordingly.

Results:

While the results section already give relevant information, it could be partly rewritten to strengthen the data.

Lines 183-198: this part could benefit from some rewriting to improve the understanding. While information about the observation of all parts the biliary tree is given for the control, it is not the case for the GBM group. Lines 191-192 it is not clear whether the statement about the cystic duct concerned the entire group or the immobile GBM cases. Lines 195-196: The order of the sentences might also be improved, for example data about mucoceles are given lines 188 to 191 but again at line 194; data about CBD/duodenum lines 192-193 but again line 197. Lines 194-196, it might be more clearly stated whether any flushing was performed and if no flushing was performed why.

Line 197. If available, it could be interesting to add data regarding the length of the surgeries in each group to give information about how long the fluorescence was observed and also to be capable to comment in the discussion on whether this technic could shorten the surgical time.

Did any clinical, ultrasonographic and biological data are available about the short and long-term outcomes of the GBM cases? This information would be off great value to strengthen the statement that no side-effect from ICG developed and that no case had CBD obstruction (mainly partial obstruction) that had been missed during surgery

Table 1: maybe change “female” and “male” for “entire female” and “entire male” as usually “entire” is added to differentiate between the general gender and the reproductive status.

Figure 3: it seems that yellow and not green arrow heads can be seen on figure 3A. “HD” on figure 3B is not explicated in the legends.

Adding an image of “patency” with ICG within the duodenum would be nice.

Discussion:

In general, this section points out interesting and relevant data but it is a bit difficult to follow. In light to the previous comments, some section of the discussion would require modification, especially regarding the limitations.

The sequencing is sometimes confusing or not logical or the relevance of the information regarding the study questionable. Especially in the paragraph lines 245 to 261, the general information regarding GBM is not highly relevant and does not really explain why only elective procedure was considered.

The complications related to catherization are first mentioned line 262-263 but also again lines 303. It appears a bit redundant, while each time they are not clearly described. To better justify the search for alternative technics, a more thorough description of the complication related to catheterization would be nice.

Lines 297-300: it seems that this reference 26 is the only previous one using ICG cholangiography in dogs and it should be discussed more. Observation obtained in healthy dog in reference 26 could be compared to the observation in the current study in the control group. While references to protocols used in humans are made starting line 323, the authors could precise whether the materials and methods they used for ICG cholangiography was identical or different to the methods used in reference 26 and, to discuss why they eventually deviate from the published protocol in dogs.

Lines 318-320: this sentence seems confusing, please rephrase.

Lines 330-332: the sentence is also confusing as “the present study” would refer to the study described in the manuscript (that indeed report data regarding safety but not “less likely to cause side effects”) a

Conclusion

In light to previous comments, the conclusion should be rewritten taking into considering what was indeed demonstrated in the study and onto which cases the observation could be applied.

Lines 349-351: please give context and rephrase or remove the sentence as it is difficult to understand.

Hoping to read a 2nd version soon.

Reviewer #2: The manuscript entitled “Determining the patency of biliary tracts in dogs with gallbladder mucocele using near-infrared cholangiography with indocyanine green” introduced a study aiming to use ICG for IOC to identify fluorescent biliary tract images and determine the patency of the common bile duct during cholecystectomy in dogs. The study demonstrated that fluorescent IOC administration via intravenous injection of ICG can eliminate the need for surgical catheterization and flushing of the biliary ducts, which allows the assessment of the patency of the cystic duct and common bile duct during cholecystectomy.

There are some questions worth considering and addressing, so major revisions should be conducted before further consideration.

1. The full name of CBD should be supplemented in the abstract.

2. Tolerance of humans and animals to the same drug is very different. Generally speaking, the drug tolerance of animals is larger than people, which means animals need higher drug doses than humans. So, has the author adjusted the drug dose (0.25mg/kg was used in the study)?

3. Where is the scale bar of Figure 3?

4. Whether the authors measure the residual amount of ICG in other organs, such as the kidney, heart, spleen, and lung?

5. Is there any difference in the results between different dog types, especially between large and small dogs?

6. This research only studied whether IOC can be applied in canine cholangiography, there are limited experiments and data. I suggest more investigation into the dose of ICG administration and the detection time after ICG administration because these supplements in the experiment improve the scientific significance and reference value of this article.

7. Has the author tested the feasibility of this method on other animals?

8. There is a clerical error on Page 5 line 121 “0.25/mL”.

9. The author should pay attention to the space between numbers, symbols, and letters in the figure legends. For example, “n=6”, and “p=0.002” in page 7.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

PLoS One. 2024 May 22;19(5):e0300395. doi: 10.1371/journal.pone.0300395.r002

Author response to Decision Letter 0

17 Feb 2024

[Reviewer #1]

* Overview

However, a rather major issue in the manuscript is related to the cases included in the GBM group compared the more general statements made from the data. The inclusion criteria and so the study population are rather well described and correspond to some cases of GBM seen in clinical practice; therefore, most conclusions are valid. However, the study population does not represent all cases of GBM. This recruitment bias should be more clearly acknowledged and represent a restraint to some claims, especially the evaluation of biliary ducts patency and alleviation for catheterization. All these limitations should be highlighted and the corresponding statements should be mitigated by adding on which cases they are applicable. First, the study presents enough data to conclude that this technique permits to visualize the biliary tract in healthy dogs and dogs with GBM but without complete duct obstruction. However, it would also be nice to discuss whether a complete obstruction could limit the visualization of the biliary tract, as suggested from the images obtained from the dog presented in figure 3C. As this situation was not evaluated in this study and in the pilot one in dogs (reference 26), it would be nice to give data from the human literature. As ICG was observed in the duodenum in all dogs, at least partial patency can be considered and therefore demonstrated with this technic. However, it should be commented and discussed as to whether partial obstruction was still possible. I think that cases with obstruction should have been included to definitively conclude on the use of ICG for the assessment of the patency of the cystic and common bile duct. While it seems judicious to hypothesize (as done lines 243-244) that it could permit to demonstrate obstruction, the data presented here cannot permit to conclude definitively. The authors stated that this technic can eliminate the need for surgical catherization and flushing. It seems to be an over statement and so need to be mitigated. While it is probably true when the ducts seem patent, catherization would still be required in case of obstruction to remove the obstacle.

Response: We sincerely appreciate the thorough review conducted by the reviewer and their valuable suggestions for enhancing our manuscript. Their insights have significantly contributed to improving the quality of our work. We have revised the manuscript as per the reviewer’s comments and believe that these revisions have considerably improved the manuscript. We have addressed each of your concerns individually in the responses below.

* Specific Comment

1. Concerning question 3 (Have the authors made all data underlying the findings in their manuscript fully available), I answered no as I understood that the data policy requires that individual data are available such as the fluorescence intensity for each dog (and not a median for the group), etc. If confirmed by the Editors that it is indeed required, I would suggest to give these data as a supporting information. « The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. »

Response: We appreciate your valuable suggestion. In response to the reviewer's suggestion, we have included the necessary data as supporting information to ensure compliance with the PLOS Data Policy. Thank you for guiding us through this process.

* Abstract

2. The abstract is concise and captures some essential features of the manuscript but should be rewritten to be more accurate and to highlight the most relevant information. For example, it should precise that for GBM cases, only elective procedures were included; how fluorescence was assessed and quantified, what were the criteria to define bile duct patency.

Response: We thank the reviewer for the pertinent comments and suggestions. First, we additionally mentioned the elective procedure (page 2, lines 33-34 in the revised manuscript). Furthermore, the paragraph was rewritten, and a more detailed description was introduced, to improve clarity (Page 2, lines 35-39 in the revised manuscript).

3. On the contrary, some information is not essential such as “that underwent preoperative assessments, including imaging and biochemical analyses”.

Response: Thank you for your comment. We deleted this part.

4. Concerning the results, beyond CBD patency and gallbladder intensity, adequate visualization of the anatomy of the remaining extrahepatic biliary tree could be mentioned.

Response: We thank the reviewer for this valuable suggestion. As suggested, we additionally mentioned the visualization of the extrahepatic biliary tree (Page 2, lines 41-42 in the revised manuscript).

5. In the view of the limits discussed previously, the conclusion seems overstated and should be mitigated.

Response: Thank you for your valuable comment. As suggested, we rephrased the conclusion to better align with the acknowledged limitations discussed earlier (Page 2, lines 42-47 in the revised manuscript).

6. Line 30: if only one study has indeed been published (reference 26), “only a few studies” should be modified for “only one”

Response: We revised this sentence according to your suggestion (page 2, line 30 in the revised manuscript).

7. Line 37: please precise between what significant difference were observed or consider removing the sentence if this information is not crucial.

Response: We appreciate the suggestion. To improve clarity, we deleted this sentence to improve clarity.

* Introduction

8. The introduction is appropriate, clearly explain why the subject matters and provide some rational for the study. However, the “few studies” (lines 75-76) should be referenced and commented to justify why the present study was needed.

Response: We sincerely appreciate valuable suggestions for improvement. First, we have changed “few studies” to “only one study” and added the reference. Second, this paragraph was further rewritten, and a more detailed description was introduced, to justify why the present study was needed (page 4, lines 76-78 in the revised manuscript).

* Materials and methods 

This section could be improved by defining more precisely some criteria.

9. The study seems prospective but it should be clearly stated and the time period for recruitment (line 113) could be mentioned elsewhere than it the “informed consent” paragraph.

Response: We appreciate this suggestion. As per the reviewer’s suggestion, we deleted about time period in the “informed consent” and inserted it into the “study population and preoperative assessment” section (page 4, lines 87-88 in the revised manuscript).

10. How the number of cases to be included was determined? It might be more accurate to describe the recruitment criteria in the material and methods section but only give the number of animals effectively included in the results section, except if it was pre-determined.

Response: We thank you for your inquiry and valuable suggestions. First, for the determination of the number of cases, we set a specific period (Client-owned dogs were prospectively recruited for the study from February 2021 until August 2023.) and determined the number of cases by categorizing them based on the patients collected within that period. Second, as you suggested, we removed some sentences and gave only the number of animals effectively included in the results section and rewritten in the material and methods section to improve readability (page 5, lines 100-102 in the revised manuscript).

11. The criteria to diagnose GBM in general and to differentiate mobile vs immobile case should be define in this section (and not in the discussion).

Response: We appreciate your suggestion. As suggested, the criteria to diagnose GBM was removed from the Discussion section and included in the material and methods section (Page 5, lines 102-109 in the revised manuscript).

12. The criteria to define bile duct patency should also be clearly stated.

Response: We appreciate the insightful comment, and this clarification enhances the understanding of our methodology and criteria for assessing bile duct patency. The criteria to define bile duct patency were additionally discussed (Pages 6-7, lines 144-148 in the revised manuscript).

13. Could the authors please indicate which side effects were potentially expected and how were they monitored?

Response: We are very thankful for the valuable suggestion which has enhanced the quality of the research. We have created a new section regarding monitoring and provided additional explanations (Page 7, lines 154-163 in the revised manuscript).

14. Line 119: it would be better to precise also the maximum time period between the injection and the start of the surgery

Response: We appreciate this suggestion. As per the reviewer’s suggestion, this sentence was revised (Page 6, lines 129-130 in the revised manuscript).

15. Statistical analysis: Lines 147-148 it is stated that data were presented as median but it seems that for figures 4 and 5, mean and standard deviation were used. Please, complete the statistical analysis accordingly.

Response: We thank the reviewer for pointing this out, and we apologize for this error. We determined that the manuscript description was wrong, and therefore, we have changed “Data were presented as the median value for each group, followed by the interquartile range” to “Data were presented as means and standard deviations.” (Page 8, lines 172-173 in the revised manuscript).

* Results

16. Lines 183-198: this part could benefit from some rewriting to improve the understanding. While information about the observation of all parts the biliary tree is given for the control, it is not the case for the GBM group.

Response: We thank the reviewer for the suggestion. We have introduced the necessary changes in the revised manuscript (page 10, lines 215-218).

17. Lines 191-192 it is not clear whether the statement about the cystic duct concerned the entire group or the immobile GBM cases.

Response: We apologize for the confusion. We have modified the sentence to make it clearer (Page 10, lines 217-218 in the revised manuscript).

18. Lines 195-196: The order of the sentences might also be improved, for example data about mucoceles are given lines 188 to 191 but again at line 194; data about CBD/duodenum lines 192-193 but again line 197.

Response: Thank you for your valuable comments which helped to enhance readability. We have modified the sentence to make it clearer. (Page 10, lines 215-223 in the revised manuscript)

19. Lines 194-196, it might be more clearly stated whether any flushing was performed and if no flushing was performed why.

Response: We appreciate the reviewer for this feedback. We have revised the manuscript per your suggestion (Page 10, lines 218-220 in the revised manuscript). Additionally, to address the reason for not performing flushing, we have revised and added the following explanation the Methods & Materials section: "Bile duct patency was determined by comparing FI values. In the control group, values for the gallbladder (GB) and common bile duct (CBD) were established. When FI values of the CBD in GBM patients closely resembled those in the control group, CBD patency was considered confirmed. This criterion ensured a thorough evaluation of bile duct patency while minimizing unnecessary interventions.” (Pages 6-7, lines 144-148 in the revised manuscript).

20. Line 197. If available, it could be interesting to add data regarding the length of the surgeries in each group to give information about how long the fluorescence was observed and also to be capable to comment in the discussion on whether this technique could shorten the surgical time.

Response: Thank you for your valuable suggestion. In this study, we focused solely on elective patients and primarily on GB cholangiography; therefore, we did not measure the duration of the surgeries this time. However, in patients with CBD obstruction, the process of flushing into the duodenum could be skipped if the patency is confirmed by ICG cholangiography. And, this could contribute significantly to shortening the surgical time. In further studies, we are currently investigating patients with obstructive conditions using ICG cholangiography, both with and without flushing, and comparing surgical times, to explore this aspect further.

21. Did any clinical, ultrasonographic and biological data are available about the short and long-term outcomes of the GBM cases? This information would be off great value to strengthen the statement that no side-effect from ICG developed and that no case had CBD obstruction (mainly partial obstruction) that had been missed during surgery

Response: We appreciate your valuable comments. We have included additional information in the revised manuscript (Pages 10, lines 224-229 in the revised manuscript). We are pleased to report that all patients showed favorable outcomes, with no complications observed after surgery. Although individual patient data were considered for inclusion, we decided to prioritize the focus on GB cholangiography in our manuscript. Therefore, separate figures for radiographic or ultrasonographic data were not included.

22. Table 1: maybe change “female” and “male” for “entire female” and “entire male” as usually “entire” is added to differentiate between the general gender and the reproductive status.

Response: We thank the reviewer for this valuable suggestion. We revised this sentence as suggested (Page 9, line 196 in the revised manuscript).

23. Figure 3: it seems that yellow and not green arrow heads can be seen on figure 3A. “HD” on figure 3B is not explicated in the legends.

Response: We appreciate the reviewer for bringing this to our attention, and we apologize for the oversight. There was a mistake in the ordering of Figure 3 A and B. We have corrected this error by rearranging the figures to align with the correct sequence (Figure 3 on the re-uploaded file).

24. Adding an image of “patency” with ICG within the duodenum would be nice.

Response: We sincerely appreciate valuable suggestions for improvement. We have added a new figure (Figure 4) and figure legend that describes the “patency” with ICG within the duodenum (Page 11, lines 140-142 in the revised manuscript).

* Discussion

25. The sequencing is sometimes confusing or not logical or the relevance of the information regarding the study questionable. Especially in the paragraph lines 245 to 261, the general information regarding GBM is not highly relevant and does not really explain why only elective procedure was considered.

Response: We apologize for the confusion and appreciate the reviewer's suggestion which enhanced the clarity and readability of the manuscript.

We have modified the paragraph (Page 13, lines 279-291 in the revised manuscript). Also, we relocated some content to the materials and methods section and adjusted the sentences accordingly (Page 5, lines 100-109 in the revised manuscript). We included general information about GBM to provide context for the comparison of blood tests among the groups in the results section, as there were notable differences observed (Page 13, lines 279-282 in the revised manuscript).

Second, the decision to focus solely on elective surgeries was made because this study represents an initial step in our research journey, we aimed to establish a foundation of credibility and reliability. However, we acknowledge the importance of further investigations involving patients with CBD obstruction, which are currently in the planning stages.

26. The complications related to catheterization are first mentioned line 262-263 but also again lines 303. It appears a bit redundant, while each time they are not clearly described. To better justify the search for alternative technics, a more thorough description of the complication related to catheterization would be nice.

Response: We thank the reviewer for your valuable suggestions. We have addressed the issue of redundancy by revising the manuscript to eliminate duplicated content (Page 13, lines 288-289 in the revised manuscript). Additionally, we have added further details regarding complications related to catheterization (Page 15, lines 333-339 in the revised manuscript).

27. Lines 297-300: it seems that this reference 26 is the only previous one using ICG cholangiography in dogs and it should be discussed more. Observation obtained in healthy dog in reference 26 could be compared to the observation in the current study in the control group. While references to protocols used in humans are made starting line 323, the authors could precise whether the materials and methods they used for ICG cholangiography was identical or different to the methods used in reference 26 and, to discuss why they eventually deviate from the published protocol in dogs.

Response: We appreciate the reviewer’s valuable comments, and we acknowledge the importance of discussing Reference 26 more extensively in our manuscript. First, we would like to mention that our dosage determination was not solely based on Reference 26, as our experiments were conducted before the publication of this reference. Instead, we initially determined the dosage based on references in human medicine. Second, it should be noted that our study focused on evaluating the efficacy of a single dosage rather than comparing outcomes across various dosages. Reference 26 utilized dosages ranging from 0.05 to 0.25 mg/kg, whereas we specifically employed a dosage of 0.25 mg/kg. However, upon comparing our results with those of Reference 26, we confirmed that the dosage of 0.25 mg/kg proved to be effective in assessing patency. Also, it is crucial to emphasize that further research is warranted to explore the effects of varying dosages based on pathological conditions. We have discussed these points in the discussion section. (Page 16, lines 360-366 in the revised manuscript).

28. Lines 318-320: this sentence seems confusing, please rephrase.

Response: Thank you for your suggestion. We have revised the sentence to improve clarity (Page 16, lines 350-352 in the revised manuscript).

29. Lines 330-332: the sentence is also confusing as “the present study” would refer to the study described in the manuscript (that indeed report data regarding safety but not “less likely to cause side effects”)

Response: We apologize for the confusion and appreciate your comment. We have revised the paragraph to ensure clarity (Page 16, lines 367-373 in the revised manuscript).

* Conclusion

30. In light to previous comments, the conclusion should be rewritten taking into considering what was indeed demonstrated in the study and onto which cases the observation could be applied.

Response: We thank the reviewer for this valuable comments. We have revised the conclusion as per the reviewer’s comments and believe that these revisions have considerably improved the conclusion (Page 17, lines 384-393 in the revised manuscript).

31. Lines 349-351: please give context and rephrase or remove the sentence as it is difficult to understand.

Response: We appreciate this suggestion. As per the reviewer’s suggestion, we deleted this sentence to improve clarity.

[Reviewer #2]

* Major revisions

1. The full name of CBD should be supplemented in the abstract.

Response: We thank the reviewer for this suggestion, and we introduced the necessary changes (page 2, line 38 in the revised manuscript).

Response: We appreciate your valuable suggestion. As stated in the discussion (lines 355-360), we determined the final dosage based on various references from human medicine. Specifically, one study referenced in our discussion (Reference 26) utilized dosages ranging from 0.05 to 0.25 mg/kg for cholangiography in healthy dogs. Upon comparing our results with this study, the dosage of 0.25 mg/kg appeared suitable for evaluating patency in both studies (Page 16, lines 360-366 in the revised manuscript). However, considering pathological conditions and other factors, further investigation is warranted to determine the optimal dose for dogs.

3. Where is the scale bar of Figure 3?

Response: We appreciate your valuable suggestion. Unfortunately, the imaging device used in our study does not provide a scale reference for real-time visualization of organ sizes. While we did measure the size of the excised gallbladders post-surgery, comparing them to the intraoperative images may introduce inaccuracies due to perspective distortion. Therefore, we could not include a scale bar in Figure 3 to avoid potential inaccuracies in size estimation.

4. Whether the authors measure the residual amount of ICG in other organs, such as the kidney, heart, spleen, and lung?

Response: Thank you for the reviewer’s comment. In this study, our primary objective was to confirm the patency of the biliary tract and assess biliary tree visualization using cholangiography rather than measuring the residual amount of ICG in other organs. As such, our focus was directed towards the specific aims of this investigation. However, we acknowledge the importance of exploring the residual amount of ICG in other organs as a potential avenue for further research. Future studies could indeed delve into this aspect to provide a more comprehensive understanding of the pharmacokinetics and biodistribution of ICG in various tissues.

5. Is there any difference in the results between different dog types, especially between large and small dogs?

Response: We appreciate your inquiry. Upon reviewing the results of our study, we found minimal differences between different dog types, as indicated in Table 1. It was challenging to draw conclusive comparisons based solely on breed differences. Further investigation into potential variations between dog types, particularly between large and small breeds, may be warranted to provide a more comprehensive understanding of the implications of breed-specific factors on the outcomes of NIR cholangiography.

Response: We appreciate your insightful suggestions. We are fully aware of the importance of further investigation into the dose of ICG administration and the detection time after ICG administration. These aspects are currently under consideration, and we are planning to incorporate them into our ongoing research efforts. Your suggestions will undoubtedly contribute to the refinement and advancement of our study, and we are committed to addressing them in our future work.

7. Has the author tested the feasibility of this method on other animals?

Response: We appreciate your valuable comment. In this study, we did not conduct feasibility testing on other animals. Instead, we relied on references from previous studies involving humans, or dogs to establish the method's safety and feasibility (see references below). Considering the established safety based on these references, additional experiments on other animal species were not pursued in this study. Nonetheless, we closely monitored the canine patients both immediately after injection and post-surgery, and no adverse reactions related to ICG were observed during this study.

References:

1. Zarrinpar A, Dutson EP, Mobley C, Busuttil RW, Lewis CE, Tillou A, et al. Intraoperative Laparoscopic Near-Infrared Fluorescence Cholangiography to Facilitate Anatomical Identification: When to Give Indocyanine Green and How Much. Surg Innov. 2016;23(4): 360-5.

2. HOPE-ROSS, Monique, et al. Adverse reactions due to indocyanine green. Ophthalmology, 1994;101(3): 529-533.

3. Larose PC, Brisson BA, Sanchez A, Monteith G, Singh A, Zhang M. Near-infrared fluorescence cholangiography in dogs: A pilot study. Vet Surg. 2023.

4. GENÉ ŠKRABEC, Clara, et al. Fluorescent cholangiography with direct injection of indocyanine green (ICG) into the gallbladder: a safety method to outline biliary anatomy. Langenbeck's Archives of Surgery, 2020;405: 827-832.

8. There is a clerical error on Page 5 line 121 “0.25/mL”.

Response: We thank the reviewer for pointing this out, and we apologize for this error. We revised this sentence (page 5, line 121 in the revised manuscript).

9. The author should pay attention to the space between numbers, symbols, and letters in the figure legends. For example, “n=6”, and “p=0.002” in page 7.

Response: We appreciate the useful comments and criticisms provided by the reviewer, and, following a long and careful discussion, we agree with all the reviewer’s suggestions, and have introduced the appropriate changes in the remainder of the manuscript.

Attachment

Submitted filename: [GB]Response to Reviewers_Review2.docx

pone.0300395.s002.docx^{(26KB, docx)}

PLoS One. doi: 10.1371/journal.pone.0300395.r003

Decision Letter 1

Wenguo Cui

27 Feb 2024

Determining the patency of biliary tracts in dogs with gallbladder mucocele using near-infrared cholangiography with indocyanine green

PONE-D-23-36283R1

Dear Dr. Sungin Lee,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Wenguo Cui, Ph.D

Academic Editor

PLOS ONE

PLoS One. doi: 10.1371/journal.pone.0300395.r004

Acceptance letter

Wenguo Cui

21 Mar 2024

PONE-D-23-36283R1

PLOS ONE

Dear Dr. Lee,

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team.

At this stage, our production department will prepare your paper for publication. This includes ensuring the following:

* All references, tables, and figures are properly cited

* All relevant supporting information is included in the manuscript submission,

* There are no issues that prevent the paper from being properly typeset

If revisions are needed, the production department will contact you directly to resolve them. If no revisions are needed, you will receive an email when the publication date has been set. At this time, we do not offer pre-publication proofs to authors during production of the accepted work. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few weeks to review your paper and let you know the next and final steps.

Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

If we can help with anything else, please email us at customercare@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Professor Wenguo Cui

Academic Editor

PLOS ONE

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

S1 Fig. 1 fluorescence intensity of gallbladder and common bile duct of all patients.

(PDF)

pone.0300395.s001.pdf^{(27.9KB, pdf)}

Attachment

Submitted filename: [GB]Response to Reviewers_Review2.docx

pone.0300395.s002.docx^{(26KB, docx)}

Data Availability Statement

All relevant data are within the manuscript and its Supporting Information files.

[pone.0300395.ref001] 1.Aguirre AL, Center SA, Randolph JF, Yeager AE, Keegan AM, Harvey HJ, et al. Gallbladder disease in Shetland Sheepdogs: 38 cases (1995–2005). J Am Vet Med Assoc. 2007;231(1): 79–88. doi: 10.2460/javma.231.1.79 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref002] 2.Friesen SL, Upchurch DA, Hollenbeck DL, Roush JK. Clinical findings for dogs undergoing elective and nonelective cholecystectomies for gall bladder mucoceles. J Small Anim Pract. 2021;62(7): 547–53. doi: 10.1111/jsap.13312 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref003] 3.Putterman AB, Selmic LE, Kindra C, Duffy DJ, Risselada M, Phillips H. Influence of normograde versus retrograde catheterization of bile ducts in dogs treated for gallbladder mucocele. Vet Surg. 2021;50(4): 784–93. doi: 10.1111/vsu.13632 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref004] 4.Rossanese M, Williams P, Tomlinson A, Cinti F. Long-Term Outcome after Cholecystectomy without Common Bile Duct Catheterization and Flushing in Dogs. Animals (Basel). 2022;12(16). doi: 10.3390/ani12162112 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref005] 5.Boni L, David G, Mangano A, Dionigi G, Rausei S, Spampatti S, et al. Clinical applications of indocyanine green (ICG) enhanced fluorescence in laparoscopic surgery. Surg Endosc. 2015;29(7): 2046–55. doi: 10.1007/s00464-014-3895-x [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref006] 6.Aoki T, Murakami M, Yasuda D, Shimizu Y, Kusano T, Matsuda K, et al. Intraoperative fluorescent imaging using indocyanine green for liver mapping and cholangiography. J Hepatobiliary Pancreat Sci. 2010;17(5): 590–4. doi: 10.1007/s00534-009-0197-0 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref007] 7.Quaresima S, Balla A, Palmieri L, Seitaj A, Fingerhut A, Ursi P, et al. Routine near infra-red indocyanine green fluorescent cholangiography versus intraoperative cholangiography during laparoscopic cholecystectomy: a case-matched comparison. Surg Endosc. 2020;34(5): 1959–67. doi: 10.1007/s00464-019-06970-0 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref008] 8.Verbeek FP, Schaafsma BE, Tummers QR, van der Vorst JR, van der Made WJ, Baeten CI, et al. Optimization of near-infrared fluorescence cholangiography for open and laparoscopic surgery. Surg Endosc. 2014;28(4): 1076–82. doi: 10.1007/s00464-013-3305-9 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref009] 9.Larose PC, Brisson BA, Sanchez A, Monteith G, Singh A, Zhang M. Near-infrared fluorescence cholangiography in dogs: A pilot study. Vet Surg. 2023. doi: 10.1111/vsu.14007 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref010] 10.Crews LJ, Feeney DA, Jessen CR, Rose ND, Matise I. Clinical, ultrasonographic, and laboratory findings associated with gallbladder disease and rupture in dogs: 45 cases (1997–2007). J Am Vet Med Assoc. 2009;234(3): 359–66. doi: 10.2460/javma.234.3.359 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref011] 11.Pike FS, Berg J, King NW, Penninck DG, Webster CR. Gallbladder mucocele in dogs: 30 cases (2000–2002). J Am Vet Med Assoc. 2004;224(10): 1615–22. doi: 10.2460/javma.2004.224.1615 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref012] 12.Uno T, Okamoto K, Onaka T, Fujita K, Yamamura H, Sakai T. Correlation between ultrasonographic imaging of the gallbladder and gallbladder content in eleven cholecystectomised dogs and their prognoses. J Vet Med Sci. 2009;71(10): 1295–300. doi: 10.1292/jvms.001295 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref013] 13.Walter R, Dunn ME, d’Anjou MA, Lécuyer M. Nonsurgical resolution of gallbladder mucocele in two dogs. J Am Vet Med Assoc. 2008;232(11): 1688–93. doi: 10.2460/javma.232.11.1688 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref014] 14.HOPE-ROSS Monique, et al. Adverse reactions due to indocyanine green. Ophthalmology, 1994;101(3): 529–533. doi: 10.1016/s0161-6420(94)31303-0 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref015] 15.Lee S, Kweon OK, Kim WH. Increased Leptin and Leptin Receptor Expression in Dogs With Gallbladder Mucocele. J Vet Intern Med. 2017;31(1): 36–42. doi: 10.1111/jvim.14612 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref016] 16.Youn G, Waschak MJ, Kunkel KAR, Gerard PD. Outcome of elective cholecystectomy for the treatment of gallbladder disease in dogs. J Am Vet Med Assoc. 2018;252(8): 970–5. doi: 10.2460/javma.252.8.970 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref017] 17.Ishizawa T, Tamura S, Masuda K, Aoki T, Hasegawa K, Imamura H, et al. Intraoperative fluorescent cholangiography using indocyanine green: a biliary road map for safe surgery. J Am Coll Surg. 2009;208(1): e1–4. doi: 10.1016/j.jamcollsurg.2008.09.024 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref018] 18.Schols RM, Bouvy ND, Masclee AA, van Dam RM, Dejong CH, Stassen LP. Fluorescence cholangiography during laparoscopic cholecystectomy: a feasibility study on early biliary tract delineation. Surg Endosc. 2013;27(5): 1530–6. doi: 10.1007/s00464-012-2635-3 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref019] 19.Cassinotti E, Al-Taher M, Antoniou SA, Arezzo A, Baldari L, Boni L, et al. European Association for Endoscopic Surgery (EAES) consensus on Indocyanine Green (ICG) fluorescence-guided surgery. Surg Endosc. 2023;37(3): 1629–48. doi: 10.1007/s00464-023-09928-5 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref020] 20.Dip F, LoMenzo E, Sarotto L, Phillips E, Todeschini H, Nahmod M, et al. Randomized Trial of Near-infrared Incisionless Fluorescent Cholangiography. Ann Surg. 2019;270(6): 992–9. doi: 10.1097/SLA.0000000000003178 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref021] 21.Zroback C, Chow G, Meneghetti A, Warnock G, Meloche M, Chiu CJ, et al. Fluorescent cholangiography in laparoscopic cholecystectomy: the initial Canadian experience. Am J Surg. 2016;211(5): 933–7. doi: 10.1016/j.amjsurg.2016.01.013 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref022] 22.Pesce A, Piccolo G, La Greca G, Puleo S. Utility of fluorescent cholangiography during laparoscopic cholecystectomy: A systematic review. World J Gastroenterol. 2015;21(25): 7877–83. doi: 10.3748/wjg.v21.i25.7877 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref023] 23.Kanai H, Minamoto T, Nukaya A, Kondo M, Aso T, Fujii A, et al. Intraoperative cholangiography and bile duct flushing in 47 dogs receiving laparoscopic cholecystectomy for benign gallbladder disease: A retrospective analysis. Vet Surg. 2022;51 Suppl 1:O150–o9. doi: 10.1111/vsu.13731 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref024] 24.Hayakawa S, Sato K, Sakai M, Kutara K, Asano K, Watari T. CT cholangiography in dogs with gallbladder mucocoele. Journal of Small Animal Practice. 2018. Aug;59(8): 490–5. doi: 10.1111/jsap.12832 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref025] 25.Kanai H, Hagiwara K, Nukaya A, Kondo M, Aso T. Short-term outcome of laparoscopic cholecystectomy for benign gall bladder diseases in 76 dogs. J Vet Med Sci. 2018;80(11): 1747–53. doi: 10.1292/jvms.18-0266 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref026] 26.Malek S, Sinclair E, Hosgood G, Moens NM, Baily T, Boston SE. Clinical findings and prognostic factors for dogs undergoing cholecystectomy for gall bladder mucocele. Vet Surg. 2013;42(4): 418–26. doi: 10.1111/j.1532-950X.2012.01072.x [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref027] 27.Vlek SL, van Dam DA, Rubinstein SM, de Lange-de Klerk ESM, Schoonmade LJ, Tuynman JB, et al. Biliary tract visualization using near-infrared imaging with indocyanine green during laparoscopic cholecystectomy: results of a systematic review. Surg Endosc. 2017;31(7): 2731–42. doi: 10.1007/s00464-016-5318-7 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref028] 28.Scott J, Singh A, Mayhew PD, Brad Case J, Runge JJ, Gatineau M, et al. Perioperative Complications and Outcome of Laparoscopic Cholecystectomy in 20 Dogs. Vet Surg. 2016;45(S1): O49–o59. doi: 10.1111/vsu.12534 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref029] 29.Amsellem PM, Seim HB 3rd, MacPhail CM, Bright RM, Twedt DC, Wrigley RH, et al. Long-term survival and risk factors associated with biliary surgery in dogs: 34 cases (1994–2004). J Am Vet Med Assoc. 2006;229(9): 1451–7. doi: 10.2460/javma.229.9.1451 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref030] 30.Fabrès V, Dossin O, Reif C, Campos M, Freiche V, Maurey C, et al. Development and validation of a novel clinical scoring system for short-term prediction of death in dogs with acute pancreatitis. J Vet Intern Med. 2019;33(2): 499–507. doi: 10.1111/jvim.15421 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref031] 31.Piegols HJ, Hayes GM, Lin S, Singh A, Langlois DK, Duffy DJ. Association between biliary tree manipulation and outcome in dogs undergoing cholecystectomy for gallbladder mucocele: A multi-institutional retrospective study. Vet Surg. 2021;50(4): 767–74. doi: 10.1111/vsu.13542 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref032] 32.Hernon TL, Friend EJ, Chanoit G, Black V, Meakin LB. The effect of flushing of the common bile duct on hepatobiliary markers and short-term outcomes in dogs undergoing cholecystectomy for the management of gall bladder mucocele: A randomized controlled prospective study. Vet Surg. 2023;52(5): 697–703. doi: 10.1111/vsu.13956 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref033] 33.Zarrinpar A, Dutson EP, Mobley C, Busuttil RW, Lewis CE, Tillou A, et al. Intraoperative Laparoscopic Near-Infrared Fluorescence Cholangiography to Facilitate Anatomical Identification: When to Give Indocyanine Green and How Much. Surg Innov. 2016;23(4): 360–5. doi: 10.1177/1553350616637671 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref034] 34.Chen Q, Zhou R, Weng J, Lai Y, Liu H, Kuang J, et al. Extrahepatic biliary tract visualization using near-infrared fluorescence imaging with indocyanine green: optimization of dose and dosing time. Surg Endosc. 2021;35(10): 5573–82. doi: 10.1007/s00464-020-08058-6 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref035] 35.Ishizawa T, Kaneko J, Inoue Y, Takemura N, Seyama Y, Aoki T, et al. Application of fluorescent cholangiography to single-incision laparoscopic cholecystectomy. Surg Endosc. 2011;25(8): 2631–6. doi: 10.1007/s00464-011-1616-2 [DOI] [PubMed] [Google Scholar]

[pone.0300395.ref036] 36.van den Bos J, Wieringa FP, Bouvy ND, Stassen LPS. Optimizing the image of fluorescence cholangiography using ICG: a systematic review and ex vivo experiments. Surg Endosc. 2018;32(12): 4820–32. doi: 10.1007/s00464-018-6233-x [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0300395.ref037] 37.Speich R, Saesseli B, Hoffmann U, Neftel KA, Reichen J. Anaphylactoid reactions after indocyanine-green administration. Ann Intern Med. 1988;109(4): 345–6. doi: 10.7326/0003-4819-109-4-345_2 [DOI] [PubMed] [Google Scholar]

PERMALINK

Determining the patency of biliary tracts in dogs with gallbladder mucocele using near-infrared cholangiography with indocyanine green

Su-Hyeon Kim

Sungin Lee

Roles

Abstract

Introduction

Materials and methods

Study population and preoperative assessment

Fig 1. Patient enrollment.

Informed consent

Administration of ICG

Fluorescent imaging system

Fig 2. Flowchart of the near-infrared fluorescent cholangiography using indocyanine green (ICG) study procedure © 2023 by Sungin Lee is licensed under CC BY 4.0.

Monitoring

Statistical analysis

Results

Patients’ characteristics

Table 1. Comparison of age, sex, breed, body weight (BW), and biochemical characteristics between dogs with normal gallbladder (controls) and dogs with gallbladder mucocele.

IOC using ICG fluorescence imaging systems

Fig 3. Fluorescent intraoperative cholangiography.

Fig 4. Intraoperative view using near-infrared camera after ICG administration.

Analysis of FI in control dogs with normal GB, dogs with mobile GBM, and dogs with immobile GBM

Fig 5. Fluorescent intensity of the gallbladder (GB).

Fig 6. Fluorescent intensity of the common bile duct (CBD).

Discussion

Conclusion

Supporting information

Data Availability

Funding Statement

References

Decision Letter 0

Wenguo Cui

Roles

Author response to Decision Letter 0

Decision Letter 1

Wenguo Cui

Roles

Acceptance letter

Wenguo Cui

Roles

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

Similar articles

Cited by other articles

Links to NCBI Databases