Through-the-scope clip retention rates and performance in a porcine model.

Background and study aims Limited comparative data exist to guide optimal through-the-scope (TTS) clip selection. The aim of this study was to compare the efficacy, retention, and safety of three industry-leading TTS clips on tissue that mimics common clinical scenarios. Methods A survival study involving six domestic pigs was undertaken. Three commonly used clip models were selected: Assurance (STERIS, Mentor, Ohio, United States), Resolution (Boston Scientific, Boston, Massachusetts, United States), and SureClip (Micro-Tech, Ann Arbor, Michigan, United States). To mimic clinical practice, the following scenarios were assessed: (1) normal mucosa; (2) cold snare resection; and (3) hot mucosal resection simulating fibrotic ulcers. Deployment of clips was randomized to target sites. Repeat endoscopy was performed 2 weeks following placement. Endoscopists rated the ease of use of clip placement on a Likert scale of 1 to 5. Results Fifty-four clips (18 Assurance, 18 Resolution, and 18 SureClip) were placed in six pigs. Mucosal healing was noted at all sites on follow up. Overall retention was nine of 18 (50.0%) SureClip, 10 of 18 (55.6%) Assurance, and 13 of 18 (72.2%) Resolution ( P =0.369). There was no difference in clip retention on normal and cold snare resection sites; however, clip retention was significantly higher for Resolution clips on fibrotic ulcers (50.0% versus 0% for Assurance and 0% SureClip, P =0.03). No adverse events were reported. Ease of use was equivalent across all models. Conclusions All clips were equivalent in efficacy and safety with successful clip deployment and mucosal healing. Overall retention rate was low for fibrotic tissue, with an improved retention rate observed with Resolution clips.

Real-Time Computer-Aided Detection of Colorectal Neoplasia During Colonoscopy : A Systematic Review and Meta-analysis.

BACKGROUND: Artificial intelligence computer-aided detection (CADe) of colorectal neoplasia during colonoscopy may increase adenoma detection rates (ADRs) and reduce adenoma miss rates, but it may increase overdiagnosis and overtreatment of nonneoplastic polyps. PURPOSE: To quantify the benefits and harms of CADe in randomized trials. DESIGN: Systematic review and meta-analysis. (PROSPERO: CRD42022293181). DATA SOURCES: Medline, Embase, and Scopus databases through February 2023. STUDY SELECTION: Randomized trials comparing CADe-assisted with standard colonoscopy for polyp and cancer detection. DATA EXTRACTION: Adenoma detection rate (proportion of patients with ≥1 adenoma), number of adenomas detected per colonoscopy, advanced adenoma (≥10 mm with high-grade dysplasia and villous histology), number of serrated lesions per colonoscopy, and adenoma miss rate were extracted as benefit outcomes. Number of polypectomies for nonneoplastic lesions and withdrawal time were extracted as harm outcomes. For each outcome, studies were pooled using a random-effects model. Certainty of evidence was assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) framework. DATA SYNTHESIS: Twenty-one randomized trials on 18 232 patients were included. The ADR was higher in the CADe group than in the standard colonoscopy group (44.0% vs. 35.9%; relative risk, 1.24 [95% CI, 1.16 to 1.33]; low-certainty evidence), corresponding to a 55% (risk ratio, 0.45 [CI, 0.35 to 0.58]) relative reduction in miss rate (moderate-certainty evidence). More nonneoplastic polyps were removed in the CADe than the standard group (0.52 vs. 0.34 per colonoscopy; mean difference [MD], 0.18 polypectomy [CI, 0.11 to 0.26 polypectomy]; low-certainty evidence). Mean inspection time increased only marginally with CADe (MD, 0.47 minute [CI, 0.23 to 0.72 minute]; moderate-certainty evidence). LIMITATIONS: This review focused on surrogates of patient-important outcomes. Most patients, however, may consider cancer incidence and cancer-related mortality important outcomes. The effect of CADe on such patient-important outcomes remains unclear. CONCLUSION: The use of CADe for polyp detection during colonoscopy results in increased detection of adenomas but not advanced adenomas and in higher rates of unnecessary removal of nonneoplastic polyps. PRIMARY FUNDING SOURCE: European Commission Horizon 2020 Marie Sklodowska-Curie Individual Fellowship.

Impact of Artificial Intelligence on Colonoscopy Surveillance After Polyp Removal: A Pooled Analysis of Randomized Trials.

BACKGROUND AND AIMS: Artificial intelligence (AI) tools aimed at improving polyp detection have been shown to increase the adenoma detection rate during colonoscopy. However, it is unknown how increased polyp detection rates by AI affect the burden of patient surveillance after polyp removal. METHODS: We conducted a pooled analysis of 9 randomized controlled trials (5 in China, 2 in Italy, 1 in Japan, and 1 in the United States) comparing colonoscopy with or without AI detection aids. The primary outcome was the proportion of patients recommended to undergo intensive surveillance (ie, 3-year interval). We analyzed intervals for AI and non-AI colonoscopies for the U.S. and European recommendations separately. We estimated proportions by calculating relative risks using the Mantel-Haenszel method. RESULTS: A total of 5796 patients (51% male, mean 53 years of age) were included; 2894 underwent AI-assisted colonoscopy and 2902 non-AI colonoscopy. When following U.S. guidelines, the proportion of patients recommended intensive surveillance increased from 8.4% (95% CI, 7.4%-9.5%) in the non-AI group to 11.3% (95% CI, 10.2%-12.6%) in the AI group (absolute difference, 2.9% [95% CI, 1.4%-4.4%]; risk ratio, 1.35 [95% CI, 1.16-1.57]). When following European guidelines, it increased from 6.1% (95% CI, 5.3%-7.0%) to 7.4% (95% CI, 6.5%-8.4%) (absolute difference, 1.3% [95% CI, 0.01%-2.6%]; risk ratio, 1.22 [95% CI, 1.01-1.47]). CONCLUSIONS: The use of AI during colonoscopy increased the proportion of patients requiring intensive colonoscopy surveillance by approximately 35% in the United States and 20% in Europe (absolute increases of 2.9% and 1.3%, respectively). While this may contribute to improved cancer prevention, it significantly adds patient burden and healthcare costs.

International remote collaboration enabled inaugural endoscopic sleeve gastroplasty in Japan.

Obesity causes multiple conditions such as type 2 diabetes, cardiovascular disease, and so on, and an intervention is needed for controlling weight and improving metabolic syndrome. However, the effectiveness of lifestyle interventions and pharmacotherapy are restrictive for losing weight. Endoscopic sleeve gastroplasty (ESG) was developed as a new therapy, picking the best of both medication and surgery, less invasive and more effective. Recently, ESG is gradually spreading in Western countries, but there is Case report doesn't need conclusion/result for Japanese patients. We herein reported the first clinical case of ESG in Japan. Given the situation of the pandemic of COVID-19, we could not invite a proctor from Western countries and receive the instruction of the device setting and maneuver face to face. Thus, we conducted the training for device setting, maneuver, and operation under a web-based international remote collaboration. Eventually, we completed ESG without an adverse event. We could prove this web-based proctor system was useful through the introduction of ESG in Japan. The international remote collaboration could become a new normal even in the endoscopy field post-COVID-19 era.

Visibility evaluation of colorectal lesion using texture and color enhancement imaging with video.

Objective: To evaluate the visibility of colorectal lesions using a novel image processing algorithm, texture and color enhancement imaging (TXI), that allows the acquisition of brighter images with enhanced color and surface structure. Methods: During August-September 2019, patients referred for endoscopic treatment were prospectively recruited. Electronic data acquired while observing colorectal lesions using white light imaging (WLI) were obtained and recorded: WLI, TXI mode1 (with color enhancement), and TXI mode2 (without color enhancement) videos were constructed. The lesions were also recorded using narrow-band imaging (NBI) from the same perspective as WLI. Four video clips (WLI, TXI mode1, TXI mode2, and NBI) were made per lesion. Thereafter, video files for evaluations were prepared by randomly arranging all video clips. Finally, visualization scores were evaluated by four endoscopists, and the WLI, TXI mode1, TXI mode2, and NBI results were compared. Results: Overall, 22 patients with 68 lesions were recruited; the video file for evaluation subsequently comprised 272 randomly arranged video clips. Mean visualization scores using WLI, TXI mode1, TXI mode2, and NBI were 70.0 (±20.1), 80.5 (±18.6), 75.6 (±18.1), and 69.0 (±20.6), respectively. Mean visualization scores for flat lesions using WLI, TXI mode1, TXI mode2, and NBI were 64.1 (±21.2), 76.5 (±20.18), 71.8 (±19.4), and 64.2 (±22.0), respectively. Visualization scores using TXI mode1 were significantly better than those using WLI, TXI mode2, or NBI. Conclusions: TXI enables improved visualization of colorectal lesions, even flat lesions, than WLI and NBI. TXI may allow better detection of colorectal lesions, although further prospective studies are required.

Multi-loop traction device facilitates gastric endoscopic submucosal dissection: ex vivo pilot study and an inaugural clinical experience.

BACKGROUND: Endoscopic submucosal dissection (ESD) is technically difficult and requires considerable training. The authors have developed a multi-loop traction device (MLTD), a new traction device that offers easy attachment and detachment. We aimed to evaluate the utility of MLTD in ESD. METHODS: This ex vivo pilot study was a prospective, block-randomized, comparative study of a porcine stomach model. Twenty-four lesions were assigned to a group that undertook ESD using the MLTD (M-ESD group) and a group that undertook conventional ESD (C-ESD group) to compare the speed of submucosal dissection. In addition, the data of consecutive 10 patients with eleven gastric lesions was collected using electronic medical records to clarify the inaugural clinical outcomes of gastric ESD using MLTD. RESULTS: The median (interquartile range) speed of submucosal dissection in the M-ESD and C-ESD groups were 141.5 (60.9-177.6) mm2/min and 35.5 (20.8-52.3) mm2/min, respectively; submucosal dissection was significantly faster in the M-ESD group (p < 0.05). The rate of en bloc resection and R0 resection was 100% in both groups, and there were no perforation in either group. The MLTD attachment time was 2.5 ± 0.9 min and the MLTD extraction time was 1.0 ± 1.1 min. Clinical outcomes of MLTD in gastric ESD were almost the same as those of ex vivo pilot study. CONCLUSIONS: MLTD increased the speed of submucosal dissection in ESD and was similarly effective when used by expert and trainee endoscopists without perforation. MLTD can potentially ensure a safer and faster ESD.

Detection Accuracy and Latency of Colorectal Lesions with Computer-Aided Detection System Based on Low-Bias Evaluation.

We developed a computer-aided detection (CADe) system to detect and localize colorectal lesions by modifying You-Only-Look-Once version 3 (YOLO v3) and evaluated its performance in two different settings. The test dataset was obtained from 20 randomly selected patients who underwent endoscopic resection for 69 colorectal lesions at the Jikei University Hospital between June 2017 and February 2018. First, we evaluated the diagnostic performances using still images randomly and automatically extracted from video recordings of the entire endoscopic procedure at intervals of 5 s, without eliminating poor quality images. Second, the latency of lesion detection by the CADe system from the initial appearance of lesions was investigated by reviewing the videos. A total of 6531 images, including 662 images with a lesion, were studied in the image-based analysis. The AUC, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 0.983, 94.6%, 95.2%, 68.8%, 99.4%, and 95.1%, respectively. The median time for detecting colorectal lesions measured in the lesion-based analysis was 0.67 s. In conclusion, we proved that the originally developed CADe system based on YOLO v3 could accurately and instantaneously detect colorectal lesions using the test dataset obtained from videos, mitigating operator selection biases.

Visualization of the human enteric nervous system by probe confocal laser endomicroscopy: a first real-time observation of Hirschsprung's disease and allied disorders.

BACKGROUND: Our group previously proved that the human enteric nervous system can be visualized with confocal laser endomicroscopy after topical application of cresyl violet using surgically resected intestine specimens. The present report documents the first in vivo visualization of the human enteric nervous system with confocal laser endomicroscopy using local cresyl violet staining. The aim of this study was to evaluate the technical feasibility and clinical efficiency of confocal laser endomicroscopy in patients with Hirschsprung's disease and allied disorders in vivo. METHODS: Confocal laser endomicroscopy was performed in vivo in two patients to confirm the presence of the enteric nervous system during surgery in patients with Hirschsprung's disease and allied disorders. Cresyl violet was gently injected from the serosal side into the muscular layer of the intestine, and scanning was performed within 30 min. Then, the scanned intestines were resected, and the visualized area of the specimens was pathologically evaluated. RESULTS: The ganglion cell nuclei and the enteric nervous system network were clearly visualized intraoperatively in both cases. The morphological findings were similar to the pathological findings of the enteric nervous system in both cases although the period of visibility was brief. CONCLUSION: This study demonstrated the first, real-time observation of the enteric nervous system in humans using confocal laser endomicroscopy and suggest the potential to identify the enteric nervous system intra-operatively during surgery for Hirschsprung's disease and allied disorders.

Reducing adenoma miss rate of colonoscopy assisted by artificial intelligence: a multicenter randomized controlled trial.

BACKGROUND: We have developed the computer-aided detection (CADe) system using an original deep learning algorithm based on a convolutional neural network for assisting endoscopists in detecting colorectal lesions during colonoscopy. The aim of this study was to clarify whether adenoma miss rate (AMR) could be reduced with CADe assistance during screening and surveillance colonoscopy. METHODS: This study was a multicenter randomized controlled trial. Patients aged 40 to 80 years who were referred for colorectal screening or surveillance at four sites in Japan were randomly assigned at a 1:1 ratio to either the "standard colonoscopy (SC)-first group" or the "CADe-first group" to undergo a back-to-back tandem procedure. Tandem colonoscopies were performed on the same day for each participant by the same endoscopist in a preassigned order. All polyps detected in each pass were histopathologically diagnosed after biopsy or resection. RESULTS: A total of 358 patients were enrolled and 179 patients were assigned to the SC-first group or CADe-first group. The AMR of the CADe-first group was significantly lower than that of the SC-first group (13.8% vs. 36.7%, P < 0.0001). Similar results were observed for the polyp miss rate (14.2% vs. 40.6%, P < 0.0001) and sessile serrated lesion miss rate (13.0% vs. 38.5%, P = 0.03). The adenoma detection rate of CADe-assisted colonoscopy was 64.5%, which was significantly higher than that of standard colonoscopy (53.6%; P = 0.036). CONCLUSION: Our study results first showed a reduction in the AMR when assisting with CADe based on deep learning in a multicenter randomized controlled trial.

Artificial intelligence in endoscopy: Present and future perspectives.

Artificial intelligence (AI) has been attracting considerable attention as an important scientific topic in the field of medicine. Deep-leaning (DL) technologies have been applied more dominantly than other traditional machine-learning methods. They have demonstrated excellent capability to retract visual features of objectives, even unnoticeable ones for humans, and analyze huge amounts of information within short periods. The amount of research applying DL-based models to real-time computer-aided diagnosis (CAD) systems has been increasing steadily in the GI endoscopy field. An array of published data has already demonstrated the advantages of DL-based CAD models in the detection and characterization of various neoplastic lesions, regardless of the level of the GI tract. Although the diagnostic performances and study designs vary widely, owing to a lack of academic standards to assess the capability of AI for GI endoscopic diagnosis fairly, the superiority of CAD models has been demonstrated for almost all applications studied so far. Most of the challenges associated with AI in the endoscopy field are general problems for AI models used in the real world outside of medical fields. Solutions have been explored seriously and some solutions have been tested in the endoscopy field. Given that AI has become the basic technology to make machines react to the environment, AI would be a major technological paradigm shift, for not only diagnosis but also treatment. In the near future, autonomous endoscopic diagnosis might no longer be just a dream, as we are witnessing with the advent of autonomously driven electric vehicles.

Blood group O is a risk factor for delayed post-polypectomy bleeding.

BACKGROUND: Blood group O of ABO blood group system is considered as a risk factor for various bleeding events, but the relationship with endoscopic treatment-associated bleeding has yet to be investigated. This study aimed to evaluate whether blood group O is associated with delayed bleeding after colorectal endoscopic resection. METHODS: This was a retrospective observational study based on medical records at four university hospitals in Japan. We reviewed the records for consecutive patients who underwent colorectal endoscopic resection from January 2014 through December 2017. The primary outcome was the incidence of delayed bleeding, defined as hematochezia or melena, requiring endoscopy, transfusion, or any hemostatic intervention up to 28 days after endoscopic resection. Multivariate logistic regression analysis was performed to adjust the impact of blood group O on the delayed bleeding. RESULTS: Among 10,253 consecutive patients who underwent colorectal endoscopic resection during the study period, 8625 patients met the criteria. In total, delayed bleeding occurred in 255 patients (2.96%). The O group had significantly more bleeding events compared with the non-O group (A, B, and AB) (relative risk, 1.62 [95% confidence interval, 1.24-2.10]; P < 0.001). In multivariate logistic regression analysis, blood group O remained an independent risk factor for the bleeding (adjusted odds ratio, 1.60 [95% confidence interval, 1.18-2.17]; P = 0.002). CONCLUSIONS: Blood group O was associated with an increased risk of delayed bleeding in patients undergoing colorectal endoscopic resection. Preoperative screening for ABO blood group could improve risk assessments.

Visualization of the human enteric nervous system by confocal laser endomicroscopy in Hirschsprung's disease: An alternative to intraoperative histopathological diagnosis?

BACKGROUND: Hirschsprung's disease is a congenital abnormality of the enteric nervous system (ENS) presenting severe constipation soon after birth due to the lack of ganglion cells in the distal gut. Surgery for Hirschsprung's disease requires an intraoperative histopathological diagnosis to assess the extent of aganglionosis. Confocal laser endomicroscopy (CLE) is a novel endoscopic technique allowing real-time, in vivo analysis of cellular details during ongoing endoscopy. In this study, we evaluated the possibility of a new application of CLE to provide real-time observations of the ENS in patients with Hirschsprung's disease. In this preclinical feasibility study, we assessed the visualization of the ENS by CLE using surgically resected intestines. METHODS: The subjects were nine patients who underwent pull-through surgery for Hirschsprung's disease between September 2014 and March 2016. The colon specimens were stained with 0.1% cresyl violet and evaluated using CLE. We compared the CLE findings with those of the histopathological examination. KEY RESULTS: The ENS was clearly visualized as a ladder-like structure in the ganglionic segment but was not observed in the aganglionic segment. Of the 69 samples, corresponding positive and negative results for both CLE and the histopathology were obtained in 61 (88%). In addition, CLE was able to visualize unique, wavy structures comprising thick nerve bundles characteristic of the aganglionic/transition zone in Hirschsprung's disease. CONCLUSIONS AND INFERENCES: As a novel tool for visualizing the human ENS, CLE has the potential to revolutionize how pediatric surgeons identify the level of ganglionosis during surgery for Hirschsprung's disease and may be a superior alternative to intraoperative histopathological diagnosis.

Intra-abdominal pressure during endoscopic full-thickness resection comparing manual and automatic control insufflation: a block-randomized porcine study.

BACKGROUND AND STUDY AIMS: An automatic carbon dioxide (CO2) insufflating system (SPACE) was developed to stabilize intra-lumenal pressure (ILP) during endoscopic interventions. This study investigated whether SPACE could improve the control and monitoring of extra-lumenal intra-abdominal pressure (IAP) after establishing a perforation during endoscopic full-thickness resection (EFTR) of the gastric wall in porcine models. MATERIALS AND METHODS: After first establishing the optimal preset pressure for gastric EFTR in four pigs, we compared IAP dynamics during EFTR between manual insufflation and SPACE using a block-randomized study (n = 10). IAP was percutaneously monitored and plotted on a timeline graph every 5 s. The maximal IAP and the area under the IAP curve exceeding 10 mmHg (AUC≥10 mmHg) were compared between groups, with the agreement between IAP and endolumenally monitored ILP also analyzed for animals in the SPACE group. RESULTS: In the first study, 8 mmHg was identified as the most preferable preset pressure after establishment of the perforation. In the randomized study, the mean maximal IAP in the SPACE group was significantly lower than that in the manual insufflation group (11.0 ± 2.0 mmHg vs. 17.0 ± 3.5 mmHg; P = 0.03). The mean AUC≥10 mmHg was also significantly smaller in the SPACE group. Bland-Altman analysis demonstrated agreement between IAP and ILP within a range of ± 1.0 mmHg. CONCLUSIONS: SPACE could be used to control and safely monitor IAP during gastric EFTR by measuring ILP during perforation of the gastric wall.

Real-time computer-aided diagnosis of diminutive rectosigmoid polyps using an auto-fluorescence imaging system and novel color intensity analysis software.

Objectives: An endoscopic technique that provides ≥90% negative predictive value (NPV) for differentiating neoplastic polyps is needed for the management of diminutive (≤5 mm) rectosigmoid polyps. This study aimed to assess whether a newly developed software can achieve ≥90% NPV for differentiating rectosigmoid diminutive polyps based on the green-to-red (G/R) ratio, obtained by dividing the green color tone intensity by the red color tone intensity on autofluorescence imaging (AFI). Methods: From December 2017 to May 2018, consecutive patients with known polyps who were scheduled for endoscopic treatment at our institution were prospectively recruited. All colorectal diminutive polyps were differentiated by computer-aided diagnosis using autofluorescence imaging (CAD-AFI) using a novel software-based automatic color intensity analysis; subsequent diagnosis was made by endoscopists based on trimodal imaging endoscopy (TME), which combines AFI, white-light imaging (WLI) and magnifying narrow-band imaging (M-NBI) findings. Thereafter, all polyps were removed endoscopically, and the histopathological diagnosis was evaluated. Results: Ninety-five patients with 258 diminutive rectosigmoid polyps and 171 diminutive non-rectosigmoid polyps were enrolled. Regarding diminutive rectosigmoid polyps, the NPV for differentiating neoplastic polyps was 93.4% (184/197) [95% confidence interval (CI), 89.0%-96.4%] with CAD-AFI and 94.9% (185/195) (95% CI, 90.8%-97.5%) with TME. The accuracy, sensitivity, specificity, and positive predictive value for differentiating diminutive rectosigmoid neoplastic polyps by CAD-AFI were 91.5%, 80.0%, 95.3% and 85.2%, respectively. Conclusions: Real-time CAD-AFI was effective for differentiating diminutive rectosigmoid polyps. This objective technology, which does not require extensive training or endoscopic expertise, can contribute to the effective management of diminutive rectosigmoid polyps.

Diagnostic efficacy of dual-focus endoscopy with narrow-band imaging using simplified dyad criteria for superficial esophageal squamous cell carcinoma.

BACKGROUND: Our previous studies have shown the diagnostic utility of a newly developed dual-focus endoscope with narrow-band imaging (DF-NBI) and simplified dyad criteria for detection of superficial esophageal squamous cell carcinoma (SESCC). This clinical trial aimed to study the diagnostic efficacy of DF-NBI with dyad criteria for detecting SESCC compared to white light imaging (WLI). METHODS: This was a single-arm prospective comparative trial. We enrolled 170 consecutive high-risk patients for esophageal squamous cell carcinoma. Patients were initially examined with WLI by one independent endoscopist and then the other performed DF-NBI blinded to the WLI diagnosis to avoid a carry-over effect. Lesions showing proliferation and/or various shapes of intrapapillary capillary loops (IPCL) under DF-NBI (i.e., dyad criteria) were endoscopically diagnosed as SESCC including high-grade intraepithelial neoplasia. The primary endpoint was sensitivity of WLI and DF-NBI for detecting SESCC. The secondary endpoints were the diagnostic performance (i.e., specificity and accuracy) and inter/intra-observer concordance of DF-NBI with dyad criteria. RESULTS: A total 77 SESCCs were detected. The sensitivity of DF-NBI for SESCC was significantly higher than that of WLI (91% vs. 51%, P < 0.001). The specificity and accuracy of WLI and DF-NBI using dyad criteria were 100% vs. 84%, and 86% vs. 86%, respectively. Various shapes and proliferation of IPCL showed the highest value in inter-observer and intra-observer agreements (κ = 0.77 and 0.82, respectively). CONCLUSION: DF-NBI combined with dyad criteria may be a promising technique with a high sensitivity for diagnosis of SESCC and high inter/intra-observer agreement.

Technical feasibility of visualizing myenteric plexus using confocal laser endomicroscopy.

BACKGROUND AND AIM: In preceding studies, we identified that the myenteric plexus (MP) could be visualized with confocal laser endomicroscopy (CLE) by applying neural fluorescent probes lacking clinical safety profiling data from the submucosal side. In this study, we evaluated the technical feasibility of MP visualization using probe-based CLE (pCLE) from the serosal side with cresyl violet (CV), which has been used clinically for chromoendoscopy. METHODS: The dye affinity of CV for MP was first explored in an in vivo transgenic mouse model using neural crest derivatives labeled with green fluorescent protein. We also tested the feasibility of CV-assisted visualization of MP in human surgical specimens, wherein the tissue dying and pCLE observation were performed from the serosal side. In the human study, rate of MP visualization by pCLE was evaluated as the primary outcome. We also evaluated the sensitivity and specificity of MP visualization by pCLE, using pathological presence/absence of MP as the gold standard. RESULTS: We confirmed the dye affinity of CV to MP in all tested models. The MP appeared as brightly stained ladder-like structures with pCLE, and in the human study, MP was visualized in 12/14 (85.7%) samples, with 92.3% sensitivity and 100% specificity. In positive cases showing the ladder-like structure of MP by pCLE, the mean maximum and minimum widths of nerve strands were 54.3 (± 23.6) and 19.7 (± 6.0) µm, respectively. A ganglion was detected by pCLE in 10 cases (10/12, 83.3%). CONCLUSIONS: This study demonstrated the technical feasibility of visualizing the MP in real time by CV-assisted pCLE (UMIN-CTR number, UMIN000015056).