Narrow-band imaging with magnifying endoscopy for the evaluation of gastrointestinal lesions

Narrow band imaging(NBI) endoscopy is an optical image enhancing technology that allows a detailed inspection of vascular and mucosal patterns, providing the ability to predict histology during real-time endoscopy. By combining NBI with magnification endoscopy(NBI-ME), the accurate assessment of lesions in the gastrointestinal tract can be achieved, as well as the early detection of neoplasia by emphasizing neovascularization. Promising results of the method in the diagnosis of premalignant and malignant lesions of gastrointestinal tract have been reported in clinical studies. The usefulness of NBI-ME as an adjunct to endoscopic therapy in clinical practice, the potential to improve diagnostic accuracy, surveillance strategies and cost-saving strategies based on this method are summarized in this review. Various classification systems of mucosal and vascular patterns used to differentiate preneoplastic and neoplastic lesions have been reviewed. We concluded that the clinical applicability of NBI-ME has increased, but standardization of endoscopic criteria and classification systems, validation in randomized multicenter trials and training programs to improve the diagnostic performance are all needed before the widespread acceptance of the method in routine practice. However, published data regarding the usefulness of NBI endoscopy are relevant in order to recommend the method as a reliable tool in diagnostic and therapy, even for less experienced endoscopists.     

Single balloon enteroscopy: Technical aspects and clinical applications

The small bowel has long been considered a black box for endoscopists because of its long length and the presence of multiple complex loop. Most of the small bowel is inaccessible by traditional endoscopic means. In addition, radiographic studies have significant limitations with regard to diagnostic yield, and surgery is an invasive alternative. This limitation was overcome through the development of balloon enteroscopy that becomes established throughout the world for diagnostic and therapeutic examinations of the small bowel. The single-balloon enteroscope (SBE) system (Olympus, Tokyo, Japan) was introduced into the commercial market in 2007. Several study demonstrated its efficacy and safety. Early reports on the use of singleballoon enteroscopy have suggested a high diagnostic yield and similar therapeutic potential to that of the double-balloon endoscope. SBE is viable technique for in the management of small bowel disease. Technically, it is easy to perform, may be efficient, and in the literature data available, seems to provide high diagnostic and therapeutic yield.     

Endoscopic therapy of benign biliary strictures

Benign biliary strictures are being increasingly treated with endoscopic techniques. The benign nature of the stricture should be first confirmed in order to ensure appropriate therapy. Surgery has been the traditional treatment, but there is increasing desire for minimally invasive endoscopic therapy. At present, endoscopy has become the first line approach for the therapy of post- liver transplant anastomotic strictures and distal （Bismuth ! and I） post-operative strictures. Strictures related to chronic pancreatitis have proven more difficult to treat, and endoscopic therapy is reserved for patients who are not surgical candidates. The preferred endoscopic approach is aggressive treatment with gradual dilation of the stricture and insertion of multiple plastic stents. The use of uncovered self expandable metal stents should be discouraged due to poor long-term results. Treatment with covered metal stents or bioabsorbable stents warrants further evaluation. This area of therapeutic endoscopy provides an ongoing opportunity for fresh research and innovation.     

Optimal management of biopsy-proven low-grade gastric dysplasia

Gastric adenocarcinoma generally culminates via the inflammation-metaplasia-dysplasia-carcinoma sequence progression. The prevalence of gastric adenomas shows marked geographic variation. Recently, the rate of diagnosis of low-grade dysplasia(LGD) has increased due to increased use of upper endoscopy. Many investigators have reported that gastric highgrade dysplasia has high potential for malignancy and should be removed; however, the treatment for gastric LGD remains controversial. Although the risk of LGD progression to invasive carcinoma has been reported to be inconsistent, progression has been observed during follow-up. Additionally, the rate of upgraded diagnosis in biopsy-proven LGD is high. Therefore, endoscopic resection(ER) may be useful in the treatment and diagnosis of LGD, especially if lesions are found to have risk factors for upgraded histology after ER, such as large size, surface erythema or depressed morphology. Fatal complications in endoscopic submucosal dissection(ESD) are extremely low and its therapeutic and diagnostic outcomes are excellent. Therefore, ESD should be applied preferentially instead of endoscopic mucosal resection.     

Role of narrow band imaging in endoscopic submucosal dissection

Narrow band imaging(NBI) is a new image enhancement system employing optic digital methods to enhance images of blood vessels on mucosal surfaces,allowing improved visualization of mucosal surface structures.Studies have progressed over the last several years,and the clinical usefulness has been demonstrated.NBI has become frequently applied for preoperative diagnosis before endoscopic submucosal dissection(ESD) of digestive tract cancers,as well as for assessment of the range of ESD for en-bloc resection of large lesions.Consensus has been reached with regard to the usefulness of NBI for detecting micro-lesions of esophageal squamous cell carcinoma indicated for ESD,for the diagnosis of the range and depth.NBI has also been attracting attention for diagnosing gastric cancer based on the observation of micro blood vessels on the mucosal surface and mucosal surface microstructures.The usefulness of NBI has been reported in relation to various aspects of colon cancer,including diagnoses of the presence,quality,range,and depth of lesions.However,as NBI has not surpassed diagnostic methods based on magnifying observation combined with the established and widely employed dye method,its role in ESD is limited at present.Although NBI is very useful for the diagnosis of digestive tract cancers,comprehensive endoscopic diagnosis employing the combination of conventional endoscopy including dye spraying,EUS,and NBI may be important and essential for ESD.     

Five years＇experience with capsule endoscopy in a single center

Capsule endoscopy （CE） is a novel technology that facilitates highly effective and noninvasive imaging of the small bowel. Although its efficacy in the evaluation of obscure gastrointestinal bleeding （OGIB） has been proven in several trials, data on uses of CE in different small bowel diseases are rapidly accumulating in the literature, and it has been found to be superior to alternative diagnostic tools in a range of such diseases. Based on literature evidence, CE is recommended as a first-line investigation for OGIB after negative bidirectional endoscopy. CE has gained an important role in the diagnosis and follow-up of Crohn＇s disease and celiac disease and in the surveillance of small bowel tumors and polyps in selected patients. Capsule retention is the major complication, with a frequency of 1%-2%. The purpose of this review was to discuss the procedure, indications, contraindications and adverse effects associated with CE. We also review and share our five-year experience with CE in various small bowel diseases. The recently developed balloon-assisted enteroscopies have both diagnostic and therapeutic capability. At the present time, CE and balloon-assisted enteroscopies are complementary techniques in the diagnosis and management of small bowel diseases.     

Treatment of refractory diabetic gastroparesis: Western medicine and traditional Chinese medicine therapies

Refractory diabetic gastroparesis(DGP),a disorder that occurs in both type 1 and type 2 diabetics,is associated with severe symptoms,such as nausea and vomiting,and results in an economic burden on the health care system.In this article,the basic characteristics of refractory DGP are reviewed,followed by a discussion of therapeutic modalities,which encompasses the definitions and clinical manifestations,pathogenesis,diagnosis,and therapeutic efficacy evaluation of refractory DGP.The diagnostic standards assumed in this study are those set forth in the published literature due to the absence of recognized diagnosis criteria that have been assessed by an international organization.The therapeutic modalities for refractory DGP are as follows:drug therapy,nutritional support,gastricelectrical stimulation,pyloric botulinum toxin injection,endoscopic or surgical therapy,and traditional Chinese treatment.The therapeutic modalities may be used alone or in combination.The use of traditional Chinese treatments is prevalent in China.The effectiveness of these therapies appears to be supported by preliminary evidence and clinical experience,although the mechanisms that underlie these effects will require further research.The purpose of this article is to explore the potential of combined Western and traditional Chinese medicine treatment methods for improved patient outcomes in refractory DGP.     

Radiation dose to patients during endoscopic retrograde cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) is an important tool for the diagnosis and treatment of the hepatobiliary system. The use of fluoroscopy to aid ERCP places both the patient and the endoscopy staff at risk of radiation-induced injury. Radiation dose to patients during ERCP depends on many factors, and the endoscopist cannot control some variables, such as patient size, procedure type, or fluoroscopic equipment used. Previous reports have demonstrated a linear relationship between radiation dose and fluoroscopy duration. When fluoroscopy is used to assist ERCP, the shortest fluoroscopy time possible is recommended. Pulsed fluoroscopy and monitoring the length of fluoroscopy have been suggested for an overall reduction in both radiation exposure and fluoroscopy times. Fluoroscopy time is shorter when ERCP is performed by an endoscopist who has many years experience of performing ERCP and carried out a large number of ERCPs in the preceding year. In general, radiation exposure is greater during therapeutic ERCP than during diagnostic ERCP. Factors associated with prolonged fluoroscopy have been delineated recently, but these have not been validated.     

Patency and agile capsules

Small bowel strictures can be missed by current diagnostic methods. The Patency capsule is a new non-endoscopic dissolvable capsule which has as an objective of checking the patency of digestive tract, in a non-invasive manner. The available clinical trials have demonstrated that the Patency capsule is a good tool for assessment of the functional patency of the small bowel, and it allows identification of those patients who can safely undergo a capsule endoscopy, despite clinical and radiographic evidence of small-bowel obstruction. Some cases of intestinal occlusion have been reported with the Patency capsule, four of them needed surgery. So, a new capsule with two timer plugs （Agile capsule） has been recently developed in order to minimize the risk of occlusion. This new device stars its dissolution process earlier （30 h after ingestion） and its two timer plugs have been designed to begin the disintegration even when the device is blocked in a tight stricture.     

Cystic neoplasms of the pancreas： A diagnostic challenge

Cystic neoplasms of the pancreas are increasingly recognized due to the expanding use and improved sensitivity of cross-sectional abdominal imaging. Major advances in the last decade have led to an improved understanding of the various types of cystic lesions and their biologic behavior. Despite significant improvements in imaging technology and the advent of endoscopic-ultrasound （EUS）-guided fine- needle aspiration, the diagnosis and management of pancreatic cystic lesions remains a significant clinical challenge. The first diagnostic step is to differentiate between pancreatic pseudocyst and cystic neoplasm. If a pseudocyst has been effectively excluded, the cornerstone issue is then to determine the malignant potential of the pancreatic cystic neoplasm. In the majority of cases, the correct diagnosis and successful management is based not on a single test but on incorporating data from various sources including patient history, radiologic studies, endoscopic evaluation, and cyst fluid analysis. This review will focus on describing the various types of cystic neoplasms of the pancreas, their malignant potential, and will provide the clinician with a comprehensive diagnostic approach.     

Endoscopic treatment of an impacted pancreatic duct stone using a balloon catheter for electrohydraulic lithotripsy without pancreatoscopy

Obstructing main pancreatic duct (PD) stones represent a challenge for endoscopic removal because they are frequently impacted within the duct, are hard, and process sharp edges. Multiple series have been published demonstrating that removal of obstructing stones in the main PD can improve symptoms in the majority of patients with chronic pancreatitis. Extracorporeal shock wave lithotripsy (ESWL) has become an accepted technique to facilitate stone clearance when standard endoscopic methods fail. More recently, direct contact lithotripsy with the use of smaller caliber endoscopes has been described as an alternative to ESWL. Limited experience suggests that intraductal electrohydraulic lithotripsy under direct endoscopic visualization with a small caliber pancreatoscope results in successful fragmentation of PD stones that have been refractory to standard endoscopic methods or ESWL. Herein, we report the use of intraductal electrohydraulic lithotripsy to fragment a large obstructing PD stone guided only by fluoroscopy without the utilization of a pancreatoscope.     

Update in biliary endoscopy

Biliary endoscopy has seen the development of several new techniques in the last few years. Its current role includes direct diagnostic imaging, tissue sampling, early diagnosis and palliation of biliary tumors. Relatively new methods for biliary stones management are electrohydraulic lithotripsy combined with choledochoscope guidance and laser lithotripsy. Intraductal ultrasound, confocal laser endomicroscopy and optical coherence tomography are emerging, purely diagnostic endoscopic tools in biliary endoscopy. Cytological examinations such as digital imaging analysis and fluorescence in situ hybridization have the potential of becoming very important in the early diagnosis of biliary tumors. Direct visualization of the biliary mucosa and tissue sampling can be done with the last generation of cholangioscopes. All these tools are promising, especially for the 'undetermined biliary strictures'. Improvements in quality of life, survival and biliary drainage in patients with non-operable cholangiocarcinoma have been reported after the application of both photodynamic therapy and high-dose rate intraluminal brachytherapy. Drug-eluting stents with incorporated anti-tumor agents designed to improve patency and reduce the risk of tumor ingrowth have already been tested, and other stents are under investigation as well.     

Endoscopic management of bile duct stones

The advantages of endoscopic retrograde cholangiopancreatography (ERCP) over open surgery make it the predominant method of treating choledocholithiasis. Today, technologic advances such as magnetic resonance cholangiopancreatography and laparoscopic surgery are challenging ERCP's primacy in the management of common bile duct (CBD) stones. This article reviews the current status of endoscopic treatment of biliary stones and examines this in relation to laparoscopic management. The techniques and safety of endoscopic sphincterotomy and balloon sphincteroplasty are reviewed. Balloon sphincteroplasty should be limited to study protocols because of safety questions and inherent limitations. After sphincterotomy, 85% to 90% of CBD stones can be removed with a Dormia basket or balloon catheter. These techniques are described as having both advantages and disadvantages. Methods for managing "difficult stones" include mechanical lithotripsy, intraductal shock wave lithotripsy, extracorporeal shock wave lithotripsy, chemical dissolution, and biliary stenting. These approaches are presented along with data supporting their use in specific situations. Laparoscopic cholecystectomy has emerged as the preferred alternative to open cholecystectomy. Parallel advances in the endoscopic and laparoscopic management of CBD stones have made the issue regarding the optimal treatment strategy complex. Three approaches to the management of choledocholithiasis in the laparoscopic era are presented as follows: strict therapeutic splitting, flexible therapeutic splitting, and strict laparoscopic management. The optimal approach needs to be defined in prospective comparative trials. For now, preoperative endoscopic stone extraction should still be recommended as the approach of choice in patients suspected to have CBD stones based on clinical, biochemical, and imaging parameters. Primary laparoscopic evaluation and management is reasonable in patients who have a low-to-moderate probability of having CBD stones.     

Cholangioskopie

Cholangioscopy is an important component of the management of a selected group of patients with biliary diseases. Due to the advantage of direct visualization cholangioscopy provides targeted diagnostic and therapeutic procedures under endoscopic control. Thus cholangioscopy improves the differentiation of benign and malignant intraductal lesions, targeted biopsies and precise delineation of intraductal tumor spread before surgical resection. Furthermore lithotripsy of difficult bile duct stones, ablative therapies for biliary malignancies and direct biliary drainage can be carried out under endoscopic control. Recent developments of new types of conventional peroral cholangioscopy permit feasible, safe and effective procedures that can broaden the use of this technique at reasonable costs. Hence the spectrum of diagnostic and therapeutic interventions under cholangioscopic control will be further expanded in the future.     

Clinical utility of intraductal US for evaluation of choledocholithiasis

BACKGROUND: Intraductal US can improve the diagnostic accuracy of cholangiography performed under C-arm fluoroscopy in patients with suspected choledocholithiasis. This study aimed to determine the clinical utility of intraductal US for patient management. METHODS: Patients with suspected choledocholithiasis undergoing ERCP with a C-arm fluoroscope at two tertiary academic medical centers were enrolled. After initial cholangiography, findings and decisions concerning the need for further interventions were recorded. Intraductal US (20 MHz) was then selectively performed in patients with equivocal cholangiography or those without cholangiographic evidence of bile duct stones. Intraductal US was also performed after endoscopic sphincterotomy and stone extraction to confirm bile duct clearance. RESULTS: Fifty-two patients (28 men, 24 women) were enrolled and intraductal US was selectively performed in 35 (64%). Of the 21 patients with normal cholangiography, 8 (38%) had stones or sludge by intraductal US. Endoscopic sphincterotomy was performed as a direct result of intraductal US in these 8 and the findings were confirmed in 7. In the 14 patients in whom cholangiography demonstrated small (<5 mm) or round filling defects, intraductal US concurred in 9 and found air bubble/no stone in 5. Sphincterotomy was avoided in these 5 patients. Overall, intraductal US led to a change in clinical management in 13 of 35 patients (37%) in whom it was performed. CONCLUSIONS: Selective use of intraductal US affects the clinical management of a large proportion of patients who undergo C-arm fluoroscopy-guided ERCP for suspected bile duct stones.     

Role of digital single-operator cholangioscopy in the diagnosis and treatment of biliary disorders

Due to the need for improvement in the diagnosis and minimally invasive therapy of the bile duct disorders new technologies for cholangioscopy have been recently developed. Per-oral cholangioscopy has become an important diagnostic and therapeutic tool leading to avoidance of aggressive and unnecessary surgery in many clinical scenarios. This paper focuses on the newly developed SpyGlass DS technology, its advantages, and the technique of single-operator cholangioscopy(SOC), biliary indications and possible adverse events. We also review the available literature; discuss the limitations and future expectations.Digital SOC(D-SOC) is a useful technique, which provides endoscopic imaging of the biliary tree, optical diagnosis, biopsy under direct vision and therapeutic interventions. The implementations are diagnostic and therapeutic. Diagnostic indications are indeterminate biliary strictures, unclear filling defects, staging of cholangiocarcinoma, staging of ampullary tumors(extension into the common bile duct), unclear bile duct dilation, exploring cystic lesions of the biliary tree,unexplained hemobilia, posttransplant biliary complications. Therapeutic indications are lithotripsy of difficult stones, retrieval of migrated stents, foreign body removal, guide wire placement, transpapillary gallbladder drainage and endoscopic tumor ablative therapy. Most studied and established indications are the diagnosis of indeterminate biliary stricture and intraductal lithotripsy of difficult stones. The adverse events are not different and more common compared to those of Endoscopic retrograde cholangiopancreatography(ERCP)alone. D-SOC is a safe and effective procedure, adjunct to the standard ERCP and the newly available digital technology overcomes many of the limitations of the previous generations of cholangioscopes.     

Diagnostic and therapeutic direct peroral cholangioscopy using an intraductal anchoring balloon

AIM: To report our experience using a recently introduced anchoring balloon for diagnostic and therapeutic direct peroral cholangioscopy (DPOC).METHODS: Consecutive patients referred for diagnostic or therapeutic peroral cholangioscopy were evaluated in a prospective cohort study. The patients underwent DPOC using an intraductal anchoring balloon, which was recently introduced to allow consistent access to the biliary tree with an ultraslim upper endoscope. The device was later voluntarily withdrawn from the market by the manufacturer.RESULTS: Fourteen patients underwent DPOC using the anchoring balloon. Biliary access with an ultraslim upper endoscope was accomplished in all 14 patients. In 12 (86%) patients, ductal access required sphincteroplasty with a 10-mm dilating balloon. Intraductal placement of the ultraslim upper endoscope allowed satisfactory visualization of the biliary mucosa to the level of the confluence of the right and left hepatic ducts in 13 of 14 patients (93%). Therapeutic interventions by DPOC were successfully completed in all five attempted cases (intraductal biopsy in one and DPOC guided laser lithotripsy in four). Adverse events occurred in a patient on immunosuppressive therapy who developed an intrahepatic biloma at the site of the anchoring balloon. This required hospitalization and antibiotics. Repeat endoscopic retrograde cholangiopancreatography 8 wk after the index procedure showed resolution of the biloma.CONCLUSION: Use of this anchoring balloon allowed consistent access to the biliary tree for performance of diagnostic and therapeutic DPOC distal to the biliary bifurcation.     

Intraductal Radiofrequency Ablation for Management of Malignant Biliary Obstruction

Self-expandable metal stents (SEMS) are the current standard of care for the palliative management of malignant biliary strictures. Recently, endoscopic ablative techniques with direct affect to local tumor have been developed to improve SEMS patency. Several reports have demonstrated the technical feasibility and safety of intraductal radiofrequency ablation (RFA), by both endoscopic and percutaneous approaches, in palliation of malignant strictures of the bile duct. Intraductal RFA has also been used in the treatment of occlusion of both covered and uncovered SEMS occlusion from tumor ingrowth or overgrowth. This article provides a comprehensive review of intraductal RFA in the management of malignant biliary obstruction.     

Biliary interventions using single‐operator cholangioscopy

Cholangioscopy provides an opportunity to directly visualize the bile duct for diagnosing biliary lesions and for therapeutic interventions. Although there are different cholangioscopy techniques available, single‐operator cholangioscopy has gained widespread acceptance as the standard technique for interventions in the biliary system because of its ease of use and widespread availability. Single‐operator cholangioscopy can be used for both diagnostic and therapeutic indications in the biliary tract. Diagnostic cholangioscopy is used for direct evaluation of indeterminate bile duct strictures with biopsies, diagnosing filling defects in the bile ducts observed during endoscopic retrograde cholangiography (ERC) imaging, preoperative mapping of the precise location and extension of tumors of the biliary tract, and diagnosis of intraductal neoplasms. Therapeutic cholangioscopy is used for visually guided treatment of biliary stones that have failed extraction with conventional ERC techniques, residual or impacted stones by using intraductal lithotripsy, ablation of biliary tumors and for facilitation of guidewire advancement into selective intrahepatic ducts for adequate biliary drainage. In this review, we will focus on advances in the single‐operator cholangioscopy techniques in the diagnosis and management of biliary disorders.     

Image-Enhanced Endoscopy and Its Corresponding Histopathology in the Stomach

In recent years, the technological innovation and progress of endoscopic equipment have been remarkable, and various endoscopic observation techniques have been developed. Among them, representative techniques are magnified observation and narrow-band imaging. Magnifying endoscopy with narrow-band imaging (M-NBI) can visualize superficial microanatomies in the stomach. The normal morphology of the microanatomy visualized using M-NBI differs according to the part of the stomach. The vessel plus surface (VS) classification system has been developed as a diagnostic criterion for early gastric cancer using M-NBI, and its usefulness has been proven. Based on the VS classification system, a magnifying endoscopy simple diagnostic algorithm for early gastric cancer (MESDA-G), a simplified algorithm used for early gastric cancer diagnosis, was created. We aimed to describe the anatomic structure of the stomach that can be viewed using M-NBI and outline the principles and clinical application of the VS classification system and MESDA-G. (Gut Liver 2021;15:-337)