Recent advancements in image-enhanced endoscopy in the pancreatobiliary field.

Image-enhanced endoscopy (IEE) has advanced gastrointestinal disease diagnosis and treatment. Traditional white-light imaging has limitations in detecting all gastrointestinal diseases, prompting the development of IEE. In this review, we explore the utility of IEE, including texture and color enhancement imaging and red dichromatic imaging, in pancreatobiliary (PB) diseases. IEE includes methods such as chromoendoscopy, optical-digital, and digital methods. Chromoendoscopy, using dyes such as indigo carmine, aids in delineating lesions and structures, including pancreato-/cholangio-jejunal anastomoses. Optical-digital methods such as narrow-band imaging enhance mucosal details and vessel patterns, aiding in ampullary tumor evaluation and peroral cholangioscopy. Moreover, red dichromatic imaging with its specific color allocation, improves the visibility of thick blood vessels in deeper tissues and enhances bleeding points with different colors and see-through effects, proving beneficial in managing bleeding complications post-endoscopic sphincterotomy. Color enhancement imaging, a novel digital method, enhances tissue texture, brightness, and color, improving visualization of PB structures, such as PB orifices, anastomotic sites, ampullary tumors, and intraductal PB lesions. Advancements in IEE hold substantial potential in improving the accuracy of PB disease diagnosis and treatment. These innovative techniques offer advantages paving the way for enhanced clinical management of PB diseases. Further research is warranted to establish their standard clinical utility and explore new frontiers in PB disease management.

Protocol for a Multi-Center Confirmatory Trial to Evaluate the Differential Diagnostic Performance of Contrast-Enhanced Ultrasonography Using Perflubutane in Patients with a Pancreatic Mass: A Multicenter Prospective Study.

For pancreatic masses, an evaluation of their vascularity using contrast-enhanced ultrasonography can help improve their characterization. This study was designed to evaluate the utility and safety of contrast-enhanced transabdominal ultrasonography (CE-TUS) and endoscopic ultrasonography (CE-EUS) in the diagnosis of pancreatic masses including solid or cystic masses. This multi-center comparative open-label superiority study is designed to compare Plain (P)-TUS/EUS alone with P-TUS/P-EUS plus CE-TUS/CE-EUS. Three hundred and one patients with a total of 232 solid pancreatic masses and 69 cystic masses were prospectively enrolled. The primary endpoints are to compare the diagnostic accuracy between P-TUS/P-EUS alone and P-TUS/P-EUS plus CE-TUS/CE-EUS for both the TUS and EUS of solid pancreatic masses, and to compare the diagnostic accuracy between P-EUS alone and P-EUS plus CE-EUS in cystic pancreatic masses. The secondary endpoints are to compare the diagnostic sensitivity and specificity of P-TUS/P-EUS alone and P-TUS/P-EUS plus CE-TUS/CE-EUS for pancreatic solid/cystic masses, and the accuracy of P-TUS alone and P-TUS plus CE-TUS for pancreatic cystic masses. Other secondary endpoints included comparing the diagnostic sensitivity, specificity, and accuracy of CE-TUS, CE-EUS and CE-computed tomography (CT) for solid/cystic pancreatic masses. The safety, degree of effective enhancement, and diagnostic confidence obtained with CE-TUS/CE-EUS will also be assessed.

Is preoperative pancreatic juice cytology useful for determining therapeutic strategies for patients with intraductal papillary mucinous neoplasm of the pancreas?

BACKGROUND: We compared the results of preoperative pancreatic juice cytology (PJC) and final pathological diagnosis after resection in patients who underwent resection of intraductal papillary mucinous neoplasm (IPMN) of the pancreas to determine whether preoperative PJC can help determine therapeutic strategies. METHODS: Of 1130 patients who underwent surgical resection IPMN at 11 Japanese tertiary institutions, the study included 852 patients who underwent preoperative PJC guided by endoscopic retrograde cholangiopancreatography (ERCP). RESULTS: The accuracy of preoperative PJC for differentiation between cancerous and noncancerous lesions were 55% for IPMN overall; 59% for the branch duct type; 49% for the main pancreatic duct type; 53% for the mixed type, respectively. On classifying IPMN according to the diameters of the mural nodule (MN) and main pancreatic duct (MPD), the corresponding values for diagnostic performance were 40% for type 1 (MN ≥5 mm and MPD ≥ 10 mm); 46% for type 2 (MN ≥5 mm and MPD < 10 mm); 61% for type 3 (MN < 5 mm and MPD ≥ 10 mm); 72% for type 4 (MN < 5 mm and MPD < 10 mm), respectively. CONCLUSIONS: PJC in IPMN is not a recommended examination because of its low overall sensitivity and no significant difference in diagnostic performance by type, location, or subclassification. Although the sensitivity is low, the positive predictive value is high, so we suggest that pancreatic juice cytology be performed only in cases where the patient is not sure about surgery.

Tip-in endoscopic papillectomy for ampullary adenoma near diverticulum to minimize complications.

Toyonaga and colleagues present a novel "tip-in endoscopic papillectomy" approach for resecting ampullary tumors, aiming to minimize complications like perforation and residual tumor by adapting the colonic polyp endoscopic mucosal resection tip-in method. The technique is described with accompanying video in a case of ampullary tumor near a diverticulum.

Risk factors for early and late cholecystitis after covered metal stent placement for distal biliary obstruction.

BACKGROUND: Cholecystitis is a major adverse event after self-expandable metallic stent placement for distal biliary obstruction (DBO). Covered self-expandable metallic stent (CSEMS) is being increasingly used, but few studies have investigated risk factors for cholecystitis limited to CSEMS. The present study aimed to identify risk factors for cholecystitis after CSEMS. METHODS: Patients who underwent initial CSEMS placement for DBO between November 2014 and September 2021 were enrolled and followed-up until death, recurrent biliary obstruction, cholecystitis, or until March 2022. Cholecystitis within 30 days of CSEMS was defined as early cholecystitis and after 30 days as late cholecystitis. RESULTS: Cholecystitis occurred in 51 of 339 patients (15%) after CSEMS. Forty-one patients (80.4%) had early cholecystitis, and 10 (19.6%) had late cholecystitis. Multivariate logistic regression analysis revealed that the maximum diameter of the common bile duct (CBD) (per 1 mm increase) (odds ratio [OR]: 0.87; 95% confidence interval [CI]: 0.76-1.00; p = .044), gallbladder stones (OR: 3.63; 95% CI: 1.62-8.10; p = .002), and tumor involvement in the cystic duct (CD) (OR: 4.87; 95% CI: 2.16-11.00; p < .001) were significant independent risk factors associated with early cholecystitis. No significant risk factors were identified for late cholecystitis. CONCLUSIONS: A smaller CBD diameter, gallbladder stones, and tumor involvement in the CD were identified as risk factors for early cholecystitis development after CSEMS.

A comparative study between computed tomography and endoscopic ultrasound in the detection of a mural nodule in intraductal papillary mucinous neoplasm -Multicenter observational study in Japan.

BACKGROUND/OBJECTIVES: The detection of malignancy is a major concern in the management of intraductal papillary mucinous neoplasm (IPMN). The height of the mural nodule (MN), estimated using endoscopic ultrasound (EUS) and computed tomography (CT), has been considered crucial for predicting malignant IPMN. Currently, whether surveillance using CT or EUS alone is sufficient for detecting MNs remains unclear. This study aimed to compare the ability of CT and EUS to detect MNs in IPMN. METHODS: This multicenter, retrospective observational study was conducted in 11 Japanese tertiary institutions. Patients who underwent surgical resection of IPMN with MN after CT and EUS examinations were eligible to participate. The MN detection rates between CT and EUS were examined. RESULTS: Two-hundred-and-forty patients who underwent preoperative EUS and CT had pathologically confirmed MNs. The MN detection rates of EUS and CT were 83% and 53%, respectively (p < 0.001). Additionally, the MN detection rate of EUS was significantly higher than that of CT regardless of morphological type (76% vs. 47% in branch-duct-type IPMN; 90% vs. 54% in mixed IPMN; 98% vs. 56% in main-duct-type IPMN; p < 0.001). Further, pathologically confirmed MNs ≥5 mm were more frequently observed on EUS than on CT (95% vs. 76%, p < 0.001). CONCLUSIONS: EUS was superior to CT for the detection of MN in IPMN. EUS surveillance is essential for the detection of MNs.

Prophylactic endoscopic gallbladder stent placement for cholecystitis after covered metal stent placement for distal biliary obstruction (with video).

BACKGROUND AND AIMS: Acute cholecystitis is occasionally observed after biliary drainage using a covered self-expandable metal stent (CSEMS) for distal biliary obstruction (DBO). Gallbladder drainage before CSEMS placement may reduce cholecystitis. This study aimed to examine the preventive effect of endoscopic gallbladder stent placement (EGBS) on cholecystitis with CSEMSs. METHODS: We retrospectively analyzed patients with DBO who underwent CSEMS placement across the orifice of the cystic duct between November 2014 and October 2021 and were negative for cholecystitis on biliary drainage. Prophylactic EGBS was attempted before CSEMS placement. The incidence of cholecystitis was compared between patients with and without EGBS. RESULTS: In total, 286 patients (128 men; median age, 75 years) were included in this study. EGBS was attempted in 32 patients before CSEMS placement, and technical success was achieved in 24 patients (75%). Adverse events were noted in 3 patients (9.4%; penetration of cystic duct in 1 and acute pancreatitis in 2). The cumulative incidence of cholecystitis was significantly lower in patients with EGBS than in those without EGBS (1 [4.2%] vs 56 [21.4%], P = .045). In multivariable analysis, EGBS was a significant protective factor against cholecystitis (hazard ratio, .11; 95% confidence interval, .01-.79; P = .028). CONCLUSIONS: Although the transpapillary approach to the gallbladder is not easy for patients with DBO, EGBS is effective in preventing cholecystitis associated with CSEMS placement.

Gel immersion endoscopic ultrasonography for ampullary tumors.

Toyonaga and colleagues present gel immersion endoscopic ultrasonography for ampullary tumors. They propose that gel immersion endoscopic ultrasonography is usefulness in evaluating of ampurally tumors because it allows clear and stable observation for an extended period with a low filling gel volume without papilla compression of the duodenal papilla.

Efficacy of pancreatic duct stenting to prevent postendoscopic retrograde cholangiopancreatography pancreatitis after covered self-expandable metal stent deployment.

OBJECTIVES: Although covered self-expandable metal stents (CSEMSs) are associated with the risk of postendoscopic retrograde cholangiopancreatography (ERCP) pancreatitis due to pancreatic duct (PD) orifice obstruction, they are often used for biliary drainage treatment in malignant biliary obstruction (MBO). This study aimed to investigate the efficacy of PD stenting in preventing post-ERCP pancreatitis after CSEMS implantation. METHODS: This retrospective cohort study analyzed 554 patients with transpapillary CSEMS for MBO. Patients with noninitial deployment, benign disease, CSEMS deployment above the papilla, surgically altered anatomy, uncovered self-expandable metal stents, multiple thin self-expandable metal stents, and unavailable procedure videos were excluded. Logistic regression analysis estimated the association between PD stenting and post-ERCP pancreatitis incidence. We adjusted for age, sex, pancreatitis history, prophylactic rectal nonsteroidal anti-inflammatory drug use, naïve papilla, MBO etiology, and prolonged biliary cannulation time. RESULTS: Among 554 patients, 67 (12.1%) experienced post-ERCP pancreatitis. Post-ERCP pancreatitis was recorded in 13.7% of patients in the non-PD stenting and 4.3% in the PD stenting groups. Pancreatic duct stenting was associated with lower risks of post-ERCP pancreatitis (odds ratio [OR] 0.28; 95% confidence interval [CI] 0.099-0.79; P = 0.028). In multivariable analysis, the association between PD stenting and lower post-ERCP pancreatitis incidence was consistent (OR 0.19; 95% CI 0.062-0.58; P = 0.0034). CONCLUSIONS: Pancreatic duct stenting could reduce the risk of post-ERCP pancreatitis after CSEMSs.

Re-intervention with 10-mm vs 12-mm covered self-expandable metallic stent for recurrent unresectable distal biliary obstruction in patients with previous stent implantation.

BACKGROUND: Treatment for unresectable distal malignant biliary obstruction (DMBO) involves placing a 10-mm covered self-expandable metallic stent (CSEMS). In recurrent biliary obstruction (RBO), replacement of the CSEMS is recommended; however, the appropriate stent type remains unknown. We speculated that large-bore CSEMSs would provide longer patency. We compared the efficacy of 10-mm and 12-mm CSEMS in patients with RBO. METHODS: We retrospectively retrieved data on patients who underwent CSEMS replacement from the endoscopic database. We investigated the time to RBO (TRBO) after CSEMS replacement. The hazard ratio (HR) for the the second TRBO was estimated using the Cox proportional hazard model. The estimated median second TRBO was determined using the Kaplan-Meier method. RESULTS: Among the 493 patients with DMBOs treated with 10-mm CSEMS, 48 and 29 patients underwent re-intervention with 10-mm and 12-mm CSEMS, respectively. The use of 12-mm CSEMS was inversely associated with second TRBO (multivariable-adjusted HR, 0.62; 95% CI, 0.39-0.98; P = .042). The estimated median second TRBO was greater with the 12 mm CSEMS than with the 10 mm variety (562 days vs 207 days; P = .019). CONCLUSION: The second intervention with 12-mm CSEMS was associated with a longer TRBO.

Efficacy and factors affecting procedure results of short-type single-balloon enteroscopy-assisted ERCP for altered anatomy: a multicenter cohort in Japan.

BACKGROUND AND AIMS: Although single-balloon enteroscopy (SBE)-assisted or short-type SBE (short SBE)-assisted ERCP has been reported as useful in patients with surgically altered anatomy, most studies had small sample sizes or single-center designs. This study aimed to evaluate the efficacy and factors affecting the procedure results of short SBE-assisted ERCP in patients with surgically altered anatomy. METHODS: This multicenter, retrospective study was conducted at 8 tertiary referral care centers in Japan. The data of patients who underwent ERCP-related procedures using short SBE between September 2011 and August 2019 at each facility were analyzed. RESULTS: Overall, 1318 patients were included in this analysis. The enteroscopy (reaching the target site), cannulation, and total procedural success rates were 87.9% (95% confidence interval [CI], 86.1%-89.6%), 87.0% (95% CI, 84.9%-88.8%), and 74.9% (95% CI, 72.5%-77.2%), respectively. Adverse events occurred in 7.7% of patients (95% CI, 6.4%-9.3%). Multiple logistic regression analysis indicated that age (≥75 years), Roux-en-Y reconstruction, pancreatic indication, and malignancy were factors affecting the total procedural failure. CONCLUSIONS: This large-scale study proved that short SBE-assisted ERCP in patients with surgically altered anatomy was effective. Moreover, it clarified factors affecting procedure results. Proficiency with alternative treatment techniques is required in difficult cases. (Clinical trial registration number: UMIN00004045.).

An intact boundary between the tumor and inner hypoechoic layer discriminates T1 lesions among sessile elevated gallbladder cancers.

BACKGROUND: The depth of invasion determines the surgical method for treating gallbladder cancer (GBC). However, the preoperative correct diagnosis of invasion depth, especially discrimination of T1 lesions among sessile elevated GBCs, is difficult. We investigated the utility of preoperative endoscopic ultrasound (EUS) findings for diagnosing the invasion depth. METHODS: We studied a sessile elevated GBC specimen diagnosed as a T1 lesion before developing our study protocol. EUS evidenced an intact boundary between the tumor and the inner hypoechoic layer (the intact boundary sign). To evaluate the potential of using this sign to diagnose T1 GBC as a primary outcome indicator, we retrospectively analyzed patients who underwent surgical resection of sessile elevated GBCs between April 2009 and March 2020. RESULTS: Of the 26 surgically resected sessile elevated GBC specimens, 20 were included and six were excluded due to difficulty in evaluating the overall tumor or layer structure. The Kappa coefficient for interobserver agreement regarding the intact boundary sign was 0.733. The sensitivity and specificity of the sign for diagnosing T1 lesions were 0.857 and 1.000, respectively. CONCLUSION: This new EUS finding could guide the accurate diagnosis of T1 lesions in patients with sessile elevated GBC.

Role of Endoscopic Ultrasound in the Diagnosis of Pancreatic Neuroendocrine Neoplasms.

Although pancreatic neuroendocrine neoplasms (PNENs) are relatively rare tumors, their number is increasing with advances in diagnostic imaging modalities. Even small lesions that are difficult to detect using computed tomography or magnetic resonance imaging can now be detected with endoscopic ultrasound (EUS). Contrast-enhanced EUS is useful, and not only diagnosis but also malignancy detection has become possible by evaluating the vascularity of tumors. Pathological diagnosis using EUS with fine-needle aspiration (EUS-FNA) is useful when diagnostic imaging is difficult. EUS-FNA can also be used to evaluate the grade of malignancy. Pooling the data of the studies that compared the PNENs grading between EUS-FNA samples and surgical specimens showed a concordance rate of 77.5% (κ-statistic = 0.65, 95% confidence interval = 0.59-0.71, p < 0.01). Stratified analysis for small tumor size (2 cm) showed that the concordance rate was 84.5% and the kappa correlation index was 0.59 (95% confidence interval = 0.43-0.74, p < 0.01). The evolution of ultrasound imaging technologies such as contrast-enhanced and elastography and the artificial intelligence that analyzes them, the evolution of needles, and genetic analysis, will further develop the diagnosis and treatment of PNENs in the future.

Feasibility of biliary stenting to distal malignant biliary obstruction using a novel designed metal stent with duckbill-shaped anti-reflux valve.

OBJECTIVES: Anti-reflux metal stent (ARMS) has been used to prevent recurrent biliary obstruction (RBO) due to sludge formation or food impaction. However, the most suitable ARMS remains to be identified. This study aimed to evaluate the feasibility, safety, and efficacy of biliary drainage using duckbill-shaped ARMS (D-ARMS). METHODS: This was a multicenter, retrospective observational study conducted at three Japanese tertiary institutions. Patients with distal malignant biliary obstruction who underwent biliary stenting using D-ARMS were eligible to participate. Technical success, functional success, adverse event (AE), and time to RBO (TRBO) were evaluated. RESULTS: Thirty patients underwent biliary stenting using D-ARMS from December 2018 to October 2019. The technical success rate and functional success rate were 93% and 87%, respectively. However, nonvisibility of the markers at the tip of the metal stent or spontaneous extension was occasionally observed, making biliary stenting using D-ARMS difficult. Early AE occurred in 10% of the patients including cholangitis and pancreatitis. During the median postprocedural observation time of 5.1 months (range, 0.8-22.8), RBO occurred in 33% and the median TRBO was 261 days. As for reintervention, D-ARMS could be extracted in 67% of the patients with RBO. However, the stent was torn off on removal in half of the patients. CONCLUSIONS: Although some modifications are still needed, D-ARMS was feasible and safe for biliary drainage, and sufficient TRBO was achieved. Subsequent multi-institutional studies involving a larger number of patients and a longer follow-up period are warranted to validate the present results.

Role of endoscopic ultrasound for gallbladder disease.

Endoscopic ultrasonography (EUS) has excellent spatial resolution and allows more detailed examination than abdominal ultrasonography (US) in terms of qualitative diagnosis of tumors and evaluation of tumor invasion depth. To understand the role of EUS in gallbladder disease, we need to understand the normal gallbladder wall structure and how to visualize it on EUS. In addition, gallbladder lesions can be classified into two broad categories: protuberant and wall-thickening lesions. Here, the features on EUS were outlined. We also outlined the current status of EUS-FNA for gallbladder lesions as there have been scattered reports of EUS-FNA in recent years.