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Purpose The current standard endoscopic technique is a high resolution visualisation up to Full HD and even 4 K. A recent development are 3D endoscopes providing a 3-dimensional picture, which supposedly gives additional information of depth, anatomical details and orientation in the surgical field. Since the 3D-endoscopic technique is new, little scientific evidence is known whether the new technique provides advantages for the surgeon compared to the 2D-endoscopic standard technique in FESS. This study compares the standard 2D-endoscopic surgical technique with the new commercially available 3D-endoscopic technique. Methods The prospective randomized interventional multicenter study included a total of 80 referred patients with chronic rhinosinusitis with and without polyps without prior surgery. A bilateral FESS procedure was performed, one side with the 2D-endoscopic technique, the other side with the 3D-endoscopic technique. The time of duration was measured. Additionally, a questionnaire containing 20 items was completed by 4 different surgeons judging subjective impression of visualisation and handling. Results 2D imaging was superior to 3D apart from “recognition of details”, “depth perception” and “3D effect”. For usability properties 2D was superior to 3D apart from “weight of endoscopes”. Mean duration for surgery was 26.1 min for 2D and 27.4 min. for 3D without statistical significance (P = 0.219). Conclusion Three-dimensional endoscopy features improved depth perception and recognition of anatomic details but worse overall picture quality. It is useful for teaching purposes, yet 2D techniques provide a better outcome in terms of feasibility for routine endoscopic approaches.

Recently, colorectal endoscopic submucosal dissection (ESD) obtained official approval as a standard treatment procedure in Japan. Colorectal ESD is technically more difficult and risky than gastric ESD. However, by understanding the anatomical obstacles in colorectal ESD and using proper methods and tips to overcome the difficulties, ESD is a feasible and useful treatment method for early colorectal neoplastic lesions as well. In this video, technical details of colorectal ESD using a Safe Knife are presented. This article is part of an expert video encyclopedia.

The majority of foreign body (FB) ingestions occur in children. In adults, accidental FB ingestion tends to be food (meat) bolus. Non-food FB ingestions occur more in denture users, incarcerated individuals, and patients with psychiatric disorders or alcohol intoxication. The majority of the ingested FBs will pass spontaneously. Once through the esophagus, most FBs including sharp objects pass uneventfully. Sharp or pointed FBs, animal or fish bones, and magnets increase the risk of perforation. Emergent endoscopy is indicated in: (1) esophageal obstruction when the patient is unable to swallow secretions and (2) disk batteries and sharp-pointed FBs in the esophagus. In general, esophageal FBs and food impactions without complete obstruction should be removed within 24 h (urgent endoscopy). This video manuscript describes general principles, devices, and techniques in endoscopic management of ingested FBs. Several clinical scenarios are presented. This article is part of an expert video encyclopedia.

Peptic ulcer disease is the most common cause of upper gastrointestinal (GI) bleeding. In most of the cases, bleeding from a peptic ulcer stops spontaneously. Arterial diameters in bleeding ulcers can measure up to 3.45 mm, but in most cases the diameter of the bleeding artery is small (< 2 mm). High-dose intravenous proton pump inhibitors after endoscopic therapy for a bleeding ulcer reduce recurrent bleeding risk and surgery. The endoscopic appearance of an ulcer provides important prognostic information. Clean based ulcers and ulcers with a flat pigmented spot have low rebleeding risks. Major stigmata of hemorrhage (an adherent clot, a visible vessel, or active bleeding) are associated with high rebleeding risks. Endoscopic treatment in patients with high-risk stigmata results in improved outcomes. Common endoscopic techniques and the devices used to treat upper GI ulcer bleeding, including injection therapy, thermal coagulation, endoclip application, and hemostatic powder spray are described in the given video. Different clinical scenarios are presented. This article is part of an expert video encyclopedia.

A certain group of flat lesions with a size > 10 mm that show a very flat surface are called ‘NonGranular Laterally Spreading Tumors.’ They are difficult to detect, and the risk of submucosal invasion is high when they are present; more than 20% in lesions >2 cm. Their endoscopic resection can be challenging, and they represent, as well, one of the main indications for colorectal endoscopic submucosal dissection. The hybrid resection technique, which consists of a circumferential resection followed by snare resection, is one alternative approach for lesions

Ulcerative colitis is a disease that is often encountered by endoscopists. Although endoscopic features of acute self-limiting infectious colitis overlap considerably with those of idiopathic inflammatory bowel disease, there are inflammatory changes and patterns that are suggestive of ulcerative colitis. Three cases are presented with the typical endoscopic features of ulcerative colitis with low, moderate, and severe activities. This article is part of an expert video encyclopedia.

Embryological development of the colon is complex and often unpredictable. This gives rise to variable colonic configurations during colonoscopy. An appreciation of normal colonic anatomy and three-dimensional spatial awareness of the estimated position of the colonoscope by the colonoscopist is important. Such understanding and awareness helps plan and institute specific maneuvers that are important for safe and complete examination, in addition to carrying out anatomically specific troubleshooting strategies in colonoscopy. This article is part of an expert video encyclopedia.

Sessile serrated colon polyps (SSA/Ps) are precursors to colorectal cancer. In comparison to adenomatous polyps, SSA/P can be challenging to detect during colonoscopy; they are often minimally elevated, pale, and concealed behind mucus, a colonic fold, or intraluminal debris. Because they are typically flat, located in the right side of the colon, the same color as the background mucosa, and have indistinct borders, SSA/P resection also poses challenges. The authors present examples of typical SSA/Ps that illustrate pitfalls and pearls in SSA/P detection and resection. This article is part of an expert video encyclopedia.

Endoscopic transgastric necrosectomy is a new technique that involves drainage and direct retroperitoneal endoscopic necrosectomy through the gastric wall. This procedure is demonstrated in a 67-year-old male patient who was referred for infected pancreatic necrosis due to a biliary pancreatitis. This article is part of an expert video encyclopedia.

Epidemiological data suggests that the incidence of anal carcinoma is increasing and a significant percentage of cases each year result in death. There are numerous clinical features that should raise suspicion for anal cancer. Furthermore, benign anal conditions warrant complete workup, including flexible endoscopy and anoscopy, to rule out malignancy. In this video presentation, various patient presentations are described that would raise suspicion of anal carcinoma. Also, various clinical, endoscopic, and pathological features of carcinoma of the anal canal and perianal skin as well as benign anal conditions and treatment options are shown. This article is part of an expert video encyclopedia.

The left adrenal gland is best visualized using endoscopic ultrasound (EUS) from a position in the upper body of the stomach, whereas the right adrenal gland may easily be examined using transabdominal ultrasound. The adrenal glands have a ‘seagull' configuration, with a body and two long wings. Sonographically, five layers of the adrenals may be distinguished. Mass lesions are incidentally found in up to 5% of patients, only 15–20% of these ‘incidentalomas' being clinically relevant. However, the adrenal glands are the fourth most frequent site of metastases in malignant disease. EUS-guided fine-needle aspiration biopsy of the left adrenal gland has a high yield and very low risk. This article is part of an expert video encyclopedia.

Intestinal metaplasia (IM) of the stomach is associated with a very small increased risk of developing gastric cancer. Endoscopic surveillance has been proposed and advocated for populations at risk. Risk factors for IM include Helicobacter pylori infection, high salt intake, smoking, alcohol consumption, and chronic bile reflux. IM tends to appear initially at the antrum–corpus junction, especially at the gastric angularis. As atrophy and metaplastic changes advance, they extend to the antrum and corpus. Gastric IM is categorized histopathologically into incomplete and complete types. Patients with incomplete IM should undergo endoscopic gastric mapping to define the extent of IM and rule out dysplasia or adenocarcinoma. In this video presentation, endoscopic and pathological findings in gastric IM and gastric mapping techniques has been described. This article is part of an expert video encyclopedia.

Gastric varices are present in 5–33% of patients with portal hypertension and have a reported bleeding incidence of approximately 25% in 2 years. Gastric varices are more common in patients with noncirrhotic portal hypertension and extrahepatic portal vein obstruction. The risk of bleeding from gastric varices is lower than that of esophageal variceal bleeding but is generally more severe, and the associated mortality is significantly higher. The management of gastric varices remains a therapeutic challenge. Because there are few controlled clinical trials, the strength of the evidence underlying guidelines for management of gastric varices is weaker compared to their esophageal counterparts. Traditional endoscopic sclerotherapy is ineffective because gastric varices are usually associated with a gastrorenal shunt or a gastrocaval shunt resulting in outflow into the systemic circulation and high flow rate with a resultant rapid escape of sclerosant into the systemic circulation, delayed onset of local thrombosis, and a higher risk of distal serious complications. Obturation or obliteration is the term used for gastric varices treated with glue rather than eradication, as the varix itself can remain visible even when effectively treated, as will be demonstrated in the video. This article is part of an expert video encyclopedia.

The negative initial endoscopy investigations (gastroscopy and colonoscopy) are the basic conditions for the obscure gastrointestinal (GI) bleeding diagnosis. The bleeding source is mostly localized in the small bowel; in spite of this, there is still a large group of patients with upper GI lesions missed during initial gastroscopy. Therefore, the capsule endoscopy indicated as the first-line method can be valuable for the gastric and duodenal investigation, too. Some cases of missed upper GI lesions diagnosed by means of capsule endoscopy indicated for obscure GI bleeding are demonstrated. This article is part of an expert video encyclopedia.

Gastric adenocarcinoma is still one of the most common and lethal cancers in the world. Prevention through early diagnosis of premalignant lesions and early gastric cancer could be one of the best strategies for improving survival. Endoscopy is of paramount importance for that purpose. However, endoscopic evaluation of gastric mucosa correlates poorly with histological diagnosis. New methods of electronic chromoendoscopy have emerged as potentially useful for the diagnosis of gastric lesions. The authors have recently shown that a simple high-resolution with narrow-band imaging (NBI) classification is highly accurate and reliable for the diagnosis of gastric preneoplastic and neoplastic lesions. This article shows how to apply this NBI classification for the diagnosis of gastric lesions, using video examples of all the lesions. The authors conclude that this new NBI classification can easily be applied in routine clinical practice with high accuracy. This article is part of an expert video encyclopedia.

Angiectasias are the most frequent vascular lesions in the small bowel. Unusual findings include severe segmental lymphangiectasia or idiopathic lymphangiectasia with whitish, swollen villi. Multiple small red spots or petechiae can be seen in portal hypertensive enteropathy, in rare cases even small bowel varices. Ischemic enteritis and vasculitis cause ulcerations of the small bowel. This article is part of an expert video encyclopedia.

Endoscopic submucosal dissection (ESD) is an endoscopic technique in which a gastrointestinal mucosal neoplasm can be excised by cutting through the submucosa with an endoscopic knife. It can be used with diagnostic or therapeutic intent and allows en bloc removal of the specimen. ESD usually begins with identification and evaluation of the lesion and assessment of the margin with chromo-endoscopy. The subsequent steps include marking, submucosal injection, and circumferential and submucosal dissection. Complications should be promptly recognized and dealt with immediately if necessary. This video demonstrates the main steps of the technique and management of complications. This article is part of an expert video encyclopedia.

This article describes the practical approach to endoscopic treatment of peptic ulcer bleeding and Dieulafoy's lesions including theoretical considerations of importance for the outcome. Endoscopic therapy is indicated in ulcers with active bleeding, a nonbleeding visible vessel, or an adherent clot. For high-risk ulcers (Forrest I–IIa), the authors of this article recommend initial treatment with injection of diluted adrenaline followed by a second hemostatic therapy (heater probe or clips). This article is part of an expert video encyclopedia.

Esophageal stents are widely used to treat a variety of problems, most commonly malignant dysphagia. Malignant dysphagia can be present in patients with unresectable, resectable, and potentially resectable cancer. Esophageal stents are also utilized to treat esophageal strictures, fistulas, perforations, and leaks. Stent placement usually requires both endoscopic and fluoroscopic guidances, but can be done with either modality safely. Most stents are placed distally and across the gastroesophageal junction, but proximal stent placement (which requires more precise placement) can also be performed. Complications include bleeding and perforation (which are rare) as well as migration, tumor overgrowth, and tumor ingrowth (which are more common). The techniques of placement of an esophageal stent with some tips and tricks regarding placement and management of complications are reviewed in the given video. This article is part of an expert video encyclopedia.

Characteristic endoscopic features of the small bowel are circular Kerckring's folds, orange mucosa covered with villi, and active peristalsis. Between the duodenum and terminal ileum, up to 5 m of jejunum and ileum are interposed. Impressions from outside, small venectasias, lymphatic cysts, and lymphoid hyperplasia of the terminal ileum are considered variants of normal. This article is part of an expert video encyclopedia.

A large number of endoscopic procedures have been replacing full-scale surgical intervention in the management of esophageal defects. Since 2006, the authors have developed endoscopic techniques of intracavitary and intraluminal placement of vacuum drainage systems in their institution, and so far have treated 29 cases of esophageal defects of various origins with an overall success rate of 90% (26 out of 29). With the adaptation of these procedures sponge drainages can be placed at every height of the gastrointestinal tract, thereby contributing a minimally invasive, endoscopic alternative to the management of intestinal defects. Despite promising reports in recent literature, the method-to-date is an individual treatment. 1 This article is part of an expert video encyclopedia.

Meckel's diverticulum is a remnant of the omphalomesenteric duct located in the ileum. Although typically asymptomatic, it may cause rectal bleeding in children. Owing to improved endoscopic techniques for the small bowel, it is increasingly also recognized as a potential bleeding site in adults. Endoscopic appearance is characterized by two lumina, a thickened bridge, ulcer, and occasionally direct visualization of ectopic gastric mucosa. This article is part of an expert video encyclopedia.

Gastric intestinal metaplasia (IM) is associated with a risk for development of differentiated-type gastric cancers. The diagnosis of IM is currently based on the histology of biopsy specimens because IM usually appears in flat mucosa and has few morphologic changes, and identification of IM by conventional endoscopy has high interobserver variability and a poor correlation with histological findings. Autofluorescence imaging (AFI) produces real-time images from natural tissue fluorescence from endogenous fluorophores with light excitation. Narrow band imaging (NBI) uses two specific narrow banded lights (400–430 nm and 525–555 nm) to accentuate the contrast in surface structure and microvascular architecture of the superficial mucosa. With magnification, NBI enables a detailed observation of the morphological features of the epithelium corresponding to histology. Currently, AFI and NBI are incorporated with high-resolution white-light video endoscopy in one system (tri-modal imaging). To diagnose gastric IM, selection of Helicobacter pylori positive patients is important because it increases pretest probability. For an endoscopic procedure, areas with H. pylori associated mucosal atrophy or IM are identified as areas that increase visibility of mucosal vessels and lose gastric folds in the white-light image; greenish mucosa in the gastric corpus in AFI imagery; and whitish patchy areas in NBI imagery. When the magnifying NBI is applied in the areas, IM can be diagnosed as mucosa with ridged, papillary or villiform surface structure in the corpus or mucosa, with whitish papillary or villiform surface structure in the antrum, with the light blue crest sign (white-bluish lines of light on the epithelial crests). This article is part of an expert video encyclopedia.

Malignant gastric outlet obstruction (GOO) may occur as a preterminal event in patients with a variety of unresectable cancers. Given that they provide significantly lower morbidity and mortality rates than surgical alternatives, self-expandable metallic stents (SEMS) are now widely used in the palliation of malignant GOOs. Although recently developed dedicated through-the-scope stents may facilitate the placement procedure, a full understanding of the specs and physical properties of SEMS are still essential. In addition, an understanding of optimal placement is also critical, and will aid in improving clinical efficacy and preventing potential adverse events. Here, a collection of ideas and insights into stent placement for malignant GOO is presented. This article is part of an expert video encyclopedia.

Endoscopic submucosal dissection (ESD) has been accepted as a major modality of treatment for superficial neoplasms in the gastrointestinal tract, including the esophagus. Advantages of ESD are its less invasiveness and higher curability compared to surgery and conventional endoscopic mucosal resection in the esophagus, respectively. However, ESD still poses technical difficulty. Here the authors demonstrate the technique of esophageal ESD in a patient with superficial squamous cell carcinoma. This article is part of an expert video encyclopedia.

Radiofrequency ablation (RFA) has become the first choice for treatment of dysplastic Barrett's. RFA is indicated for flat high-grade dysplasia and for eradication of residual Barrett's after endoscopic resection of any visible lesion containing high-grade dysplasia or an early mucosal cancer. RFA has a high success rate for eradication of dysplasia in 95% of patients. Eradication of intestinal metaplasia can be obtained in approximately 80% of patients. This article is part of an expert video encyclopedia.

Juvenile polyps are one of the most common sources of gastrointestinal bleeding in childhood. These polyps are nonneoplastic hamartomas that occur in up to 2% of children. The author presents the case of an 8-year-old boy with recurrent rectal bleeding due to a singular juvenile polyp. This article is part of an expert video encyclopedia.

The potential harmful effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on the stomach and duodenum is well known. NSAID-related damage to the colon is less frequently observed, but could result in inflammation, ulcers, and stricture formation. With the increasing use of NSAIDs, recognition of this phenomenon is important, because it can be confused with inflammatory bowel disease. This article is part of an expert video encyclopedia.

Diverticular bleeding is the most common cause of massive painless rectal hemorrhage, accounting for 30–50% of cases. Diverticular bleedings are arterial bleedings that mostly result from a rupture of a submucosal artery at the base of the diverticula. In more than 80% of patients, diverticular hemorrhage resolves spontaneously. An active bleeding with identification of the bleeding diverticula is demonstrated. A ruptured small arterery is detected at the base of the diverticula. This article is part of an expert video encyclopedia.

The terminal ileum contains lymphoid structures such as Peyer's patches and small lymphoid aggregations which can be quite prominent, especially in children and young adults. There is no widespread definition of the normal appearance of lymphoid tissue or what is the upper limit of normal size. Additionally, the clinical significance of apparent hyperplasia is not clear. A case of polypoid lymphoid hyperplasia of the terminal ileum detected by video capsule endoscopy is presented. This article is part of an expert video encyclopedia.

A rare cause of esophageal stenosis is intramural pseudodiverticulosis. Obstruction of the ducts of the submucosal glands in the squamous epithelium causes inflammation and this chronic inflammation leads to stricture formation. In case of strictures, dilation therapy of bougienage can be performed in order to relieve dysphagia. This article is part of an expert video encyclopedia.

Endoscopic submucosal dissection (ESD) is efficient for en bloc resection of large colorectal tumors. The main complications during ESD comprise perforation and bleeding. For the standardization of ESD, it is most important to prevent these complications. Adopting a safe strategy of ESD, the use of hyaluronic acid for injection solution, and a suitable choice of knife are efficient in the prevention of perforation and bleeding. In this article, the authors describe a safe procedure of ESD to prevent complications, especially perforation and bleeding. This article is part of an expert video encyclopedia.

The term dysplasia-associated lesional mass (DALM) refers to a heterogeneous population of endoscopically visible lesions within the colitic colon, in the course of inflammatory bowel diseases, which has an associated dysplasia in the surrounding mucosa at histology. The presence of DALM is an indication for colectomy. Here the technique of probe-based confocal laser endomicroscopy is demonstrated for in vivo characterization of DALM in a patient with chronic ulcerative colitis. This article is part of an expert video encyclopedia.

Melanosis coli refers to an abnormal brown or black pigmentation of the colonic mucosa and is frequently, but not exclusively, found in patients with long-term stimulant laxative use, particularly from the anthranoid group. The reported prevalence of endoscopically visible melanosis coli in colonoscopic studies varies widely. Some studies have shown a significant association of colorectal adenomas, but not of colorectal carcinomas, with macroscopic melanosis coli. This might be explained by the ease with which they are detected endoscopically. In the following video an extreme case of melanosis coli is shown. This article is part of an expert video encyclopedia.

Chronic radiation-induced colonic injury occurs in up to 20% of patients following radiotherapy. The rectum and distal sigmoid colon are most susceptible to radiation damage, and chronic radiation proctopathy generally manifests with anorectal pain, diarrhea, rectal bleeding, and/or anemia. Endoscopic findings include loss of mucosal vasculature, patchy erythema, and angioectasia, which correlate with ischemic endarteritis of the submucosal arterioles, submucosal fibrosis, and angioectasia on histopathological examination. Although most patients develop symptomatic chronic radiation proctopathy within 1–2 years after radiation exposure, they can present up to 30 years after treatment. Radiation proctopathy, found incidentally during endoscopy, does not warrant any therapy. Argon plasma coagulation (APC) is the mainstay of endoscopic therapy for chronic radiation proctopathy. Laser therapy and dilute formalin (2–10%) application are associated with higher complications and are not commonly utilized. In this video presentation, endoscopic findings are described in chronic radiation proctopathy and colopathy as well as APC therapy. This article is part of an expert video encyclopedia.

Radiation proctitis (RP) is a common side effect of radiation therapy to the pelvis. It often manifests as rectal bleeding. Endoscopic argon plasma coagulation (APC) is considered the best treatment option for symptomatic patients. Herein, a case with classical diagnostic features in an 85-year-old male with recent treatment for prostate cancer including therapeutic intervention using APC has been presented. This article is part of an expert video encyclopedia.

Vessels of large colonic polyps often cause postpolypectomy hemorrhage. Preligation with endoloop increases the current density and coagulates more at the site of preligation as compared with at the site of polypectomy. Ligation of stalks after polypectomy is very difficult. The Anchor clip keeps the stalk after polypectomy; in addition, the Anchor clip also suppresses the rolling up, which makes it easy to ligate the stalk. The partially placed Anchor clip draws the electrical current, avoiding burn injury around the Endoclips at the site of the polypectomy. The Anchor clip technique allows easy and safe prevention of postpolypectomy hemorrhage. This article is part of an expert video encyclopedia.

Submucosal (sm) invasion by colorectal cancer can be classified as slight (depth of invasion < 1000 µm) or massive (depth of invasion > 1000 µm). Lesions classified as sm1 and sm2 are elevated in response to sm injection, whereas lesions classified as sm3 are not elevated. When sm invasion is slight, there is negligible risk of lymphatic metastasis, and cure can be achieved by endoscopic resection alone. However, when sm invasion is massive, the risk of lymphatic metastasis is substantial, increasing with the depth of invasion. The authors previously reported that a test based on lifting indicating sm1 or sm2 lesions would have a sensitivity of 83% and a specificity of 100%, whereas a test based on nonlifting indicating sm3 lesions would have a sensitivity of 100% and a specificity of 83%. Here the evaluation of these two types of tumor, classified as lifting and nonlifting lesions, is demonstrated. This article is part of an expert video encyclopedia.

Rectal carcinoid tumors smaller than 10 mm in diameter and located within the submucosal layer have a negligible risk of lymph node involvement and distant metastasis and are suitable for endoscopic treatment. Here the authors have shown an endoscopic ultrasonography for evaluating the size and depth of carcinoid tumors and endoscopic submucosal dissection for en bloc resection. This article is part of an expert video encyclopedia.

Enterobius vermicularis (pinworm) infestation is quite common, especially in children and their caregivers. Often infection is symptomless, but more often there is perianal itching due to the adult females, which lay the eggs in the perianal region. Reinfection and person-to-person transmission is common. During colonoscopy, the adult female worms can be seen in the cecum, ascending colon, or distal ileum as white worms of 8–13 mm in length. This article is part of an expert video encyclopedia.

Accurate knowledge about the endoscopic findings in patients with Crohn's disease is of paramount importance for the endoscopist to correctly identify disease activity and for an endoscopic therapy. Moreover, recent guidelines recommend ileocolonoscopy as an outcome parameter for biological therapies or to assess therapeutic efficacy. This video focuses on the endoscopic findings in patients with Crohn's disease and provides some tips and tricks for the daily routine practice. This article is part of an expert video encyclopedia.

Patients with long-standing ulcerative colitis are at an increased risk for the development of intraepithelial neoplasia and colitis-associated cancer, and guidelines recommend colonoscopy as an outcome parameter for biological therapies or to assess therapeutic efficacy. This video highlights the various endoscopic findings in different disease stages of ulcerative colitis. The technique of advanced dysplasia detection in ulcerative colitis will be highlighted in another video of this library. This article is part of an expert video encyclopedia.

Flat lesions are recognized as more difficult to detect than protruding neoplasms. So an excellent quality colonic cleansing is desired in order to improve the detection of such lesions. However, even if bowel cleansing is excellent, flat lesions may still remain difficult to detect, as shown in the video provided. This article is part of an expert video encyclopedia.

Aberrant crypt foci (ACF) were found to be possible precursors of adenoma and cancer, as well as useful surrogate lesions for chemoprevention of colorectal cancer. The aberrant crypts are stained more darkly with methylene blue and have a thicker epithelial lining and a larger pericryptal zone than normal crypts. Recently, advanced endoscopic imaging techniques have been found to be more helpful to improve detection and characterization of ACF in the colon. For inspection of ACF, optimal bowel preparation and a high-resolution endoscope equipped with a magnifying function is required. After spraying plenty of methylene blue, the mucosal surface should be washed with plenty of water to remove the sticky mucus. Once the dark blue spot is recognized with low magnification, zooming up to the maximum point should be performed. This article is part of an expert video encyclopedia.

Clostridium difficile infection (CDI) is one of the most dreaded causes of hospital-acquired diarrhea with an increasing incidence. Frequently, CDI affects older and immunocompromised patients, but recent data suggests that even young and healthy persons who had previously not been exposed to an antimicrobial therapy are at risk. Although differential diagnosis of hospital-acquired diarrhea is broad, these patients are regularly committed to the endoscopy department. The video of this article focuses on typical endoscopic aspects of C. difficile colitis. This article is part of an expert video encyclopedia.

In clinical practice, it is often found that gastric lesions diagnosed as adenomas by pretreatment biopsy prove to be gastric cancers after endoscopic resection. Magnifying endoscopy with narrow-band imaging is a novel and excellent technique, and it helps discriminate gastric cancers from lesions and adenomas. This article is part of an expert video encyclopedia.