Endoskopische Technik

Technical innovations in endoscopy enhance the detection predominantly of flat and minute lesions. High-definition endoscopes allow visualization of fine mucosal details, especially in conjunction with digital contrast enhancement. Virtual chromoendoscopy permits characterization of lesions and exact definition of their borders. Autofluorescence imaging has the potential to serve as a red flag technique to reduce the lesion miss rate. Endomicroscopy offers microscopy of lesions during ongoing endoscopy for the first time.     

Proximal Crohn's disease: review of the clinicopathologic features and therapy.

Crohn's disease in the proximal region of the digestive tract is uncommon. Better diagnostically procedures and more careful histologic examination has led to a higher detection of proximal Crohn's disease. The diagnosis is based on symptoms, endoscopy with serial sections, or double contrast radiography. The most common histologic finding for this diagnosis are granulomas in the mucosa in Helicobacter pylori-negative patients, but the granulomas are not always frequently detected. Endoscopic lesions in the proximal regions look like the lesions that could be found in the distal regions. Notching in the duodenal folds could be a strong indication for Crohn's desease. Radiological lesions are not always characteristic, but should be used in combination with endoscopy. Stenosis is an important complication, but fistula formation and pseudodiverticular formation is possible. There is no uniform medical therapy, but the regular anti-inflammatory management for Crohn's disease is most often used. Sometimes surgery is needed.     

Role of artificial intelligence in multidisciplinary imaging diagnosis of gastrointestinal diseases

The use of artificial intelligence-based tools is regarded as a promising approach to increase clinical efficiency in diagnostic imaging, improve the interpretability of results, and support decision-making for the detection and prevention of diseases. Radiology, endoscopy and pathology images are suitable for deep-learning analysis, potentially changing the way care is delivered in gastroenterology. The aim of this review is to examine the key aspects of different neural network architectures used for the evaluation of gastrointestinal conditions, by discussing how different models behave in critical tasks, such as lesion detection or characterization (i.e. the distinction between benign and malignant lesions of the esophagus, the stomach and the colon). To this end, we provide an overview on recent achievements and future prospects in deep learning methods applied to the analysis of radiology, endoscopy and histologic whole-slide images of the gastrointestinal tract.     

Molekulare Bildgebung

Molecular imaging uses the molecular signature of cells for targeted minimally-invasive detection and characterization of gastrointestinal pathologies. Exogenous fluorescent agents serve as molecular beacons for visualization of specific surface markers or metabolic activity in the target tissue. Molecular imaging with radioactively labeled substances is well established in nuclear medicine for wide-field detection of lesions in the small intestine. In gastrointestinal endoscopy, both macroscopic detection by endogenous or exogenous fluorescence and microscopic visualization by endomicroscopy have been investigated in clinical trials, however have not yet been evaluated in larger patient cohorts. Still, molecular imaging has the potential to greatly enhance our understanding of gastrointestinal pathology and to impact on future clinical algorithms and science in gastroenterology.     

New aspects of modern endoscopy

The prognosis for patients with malignancies of the ga-strointestinal-tract is strictly dependent on early detec-tion of premalignant and malignant lesions. However, small, flat or depressed neoplastic lesions remain dif-ficult to detect with these technologies thereby limiting their value for polyp and cancer screening. At the same time computer and chip technologies have undergone major technological changes which have greatly im-proved endoscopic diagnostic investigation. New imag-ing modalities and techniques are very notable aspects of modern endoscopy. Chromoendoscopy or filter-aided colonoscopy(virtual chromoendoscopy) with high defi-nition endoscopes is able to enhance the detection and characterization of lesions. Finally, confocal laser en-domicroscopy provides histological confirmation of the presence of neoplastic changes. The developing tech-niques around colonoscopy such as the retro-viewing colonoscope, the balloon-colonoscope or the 330-de-grees-viewing colonoscope try to enhance the efficacy by reducing the adenoma miss rate in right-sided, non-polypoid lesions. Colon capsule endoscopy is limited to identifying cancer and not necessarily small adenomas. Preliminary attempts have been made to introduce this technique in clinical routine.     

Novel imaging modalities in the detection of oesophageal neoplasia

The prognosis of oesophageal neoplasia is dependent on the stage of the disease at the time of detection. Early lesions have an excellent prognosis in contrast to more advanced stages that usually have a dismal prognosis. Therefore, the early detection of these lesions is of the utmost importance. In recent years, several new techniques have been introduced to improve the endoscopic detection of early lesions. The most important improvement, in general, has been the introduction of high-resolution/high-definition endoscopy into daily clinical practice. The value of superimposing techniques such as chromoendoscopy, narrow band imaging and computed virtual chromoendoscopy onto high-resolution/high-definition endoscopy will have to be proven in randomised cross-over trials comparing these techniques with standard techniques. Important future adjuncts to white-light endoscopy serving as 'red-flag' techniques for the detection of early neoplasia may be broad field functional imaging techniques such as video autofluorescence endoscopy. In addition, real-time histopathology during endoscopy has become possible with endocytoscopy and confocal endomicroscopy. The clinical value of these techniques needs to be ascertained in the coming years.     

Advanced endoscopic imaging techniques in Crohn's disease

BackgroundEndoscopy is of pivotal importance in Crohn's disease (CD) patients for diagnosis, surveillance and assessment of disease activity and extent. Device-assisted enteroscopy (DAE) and small-bowel capsule endoscopy (SBCE) have recently changed our endoscopic approach to small-bowel imaging. Furthermore, new advanced endoscopic imaging techniques have been implemented into clinical practice to improve both characterization of mucosal inflammation and detection of dysplastic lesions.AimTo provide readers with a review about the concept of advanced endoscopic imaging for the diagnosis and characterization of CD.MethodsA literature search on the use of advanced endoscopy techniques in IBD patients was performed.ResultsDAE and SBCE allow for deep enteroscopy with high diagnostic yields and low complication's rate but their collocation in the diagnostic algorithm is still not clearly defined. Dye-based chromoendoscopy (DBC) and magnification chromoendoscopy improved dysplasia's detection in long standing colitis and prediction of inflammatory activity and extent. Dye-less chromoendoscopy (DLC) might offer the potential to replace conventional DBC for surveillance. However, both narrow band imaging and i-scan have already shown to significantly improve activity and extent assessment in comparison to white-light endoscopy. Confocal laser endomicroscopy (CLE) can detect more dysplastic lesions in surveillance colonoscopy and predict neoplastic and inflammatory changes with high accuracy compared to histology. Moreover, CLE-based molecular imaging may anticipate the therapeutic responses to biological therapy. Endocytoscopy can identify in vivo inflammatory mucosal cells harboring a new method to assess the mucosal activity.ConclusionsRecent progresses in small-bowel enteroscopy offer several potential benefits to improve both diagnosis and characterization of CD. New advanced endoscopic imaging techniques can improve detection of dysplasia and refine mucosal healing assessment, even looking beyond the morphological parameters revealed by conventional endoscopic imaging.     

Application of artificial intelligence in gastrointestinal endoscopy

With recent significant improvements in artificial intelligence (AI), especially in the field of deep learning, an increasing number of studies have evaluated the use of AI in endoscopy to detect and diagnose gastrointestinal (GI) lesions. The present review summarizes current publications on the use of AI in GI endoscopy and focuses on the challenges and future of AI‐aided systems. We expect AI to provide an effective and practical method for endoscopists in lesion detection and characterization as well as in quality control in endoscopy. However, so far, most studies have remained at the preclinical stage. More attention should be paid in the future to the use of AI in real‐life clinical applications.     

Recent Advances in Light-Induced Fluorescence Endoscopy (LIFE) of the Gastrointestinal Tract

Abstract: Gastrointestinal (GI) cancer continues to be a significant malignant disease. It is well recognized that early detection of dysplastic changes prior to invasive growth may have a pronounced effect on the clinical efficacy of treatment and subsequent patient survival. Standard white-light endoscopic visualization of such early lesions is often difficult and many premalignant lesions remain undetected during routine screening procedures. Additionally, dysplastic lesions are usually not distinguished against surrounding normal tissue, and visible non-adenomatous lesions such as hyperplastic polyps are often indistinguishable from adenomatous polyps. However, recent developments in endoscopic technology have led to the development of more sensitive endoscopic screening methods. Fluorescence-based endoscopic imaging or spectroscopy of the gastrointestinal tract may offer a novel and alternative means of detecting and identifying premalignant and malignant lesions otherwise occult to conventional white-light endoscopy. The purpose of this review is to present a general overview of the current developments and possible clinical roles of light-induced fluorescence endoscopy (LIFE) as an adjunct to conventional diagnostic endoscopy for screening and surveillance for premaligant and malignant gastrointestinal lesions. (Dig Endosc 1999; 11: 108–118)     

染色放大内镜下大肠黏膜表面微细结构改变及其临床病理意义

目的通过染色放大内镜观察不同大肠黏膜病变的Pitpattern形态,探讨其在早期大肠癌诊断中的应用价值。方法应用染色放大内镜对146例患者的大肠黏膜进行细微结构形态学观察,并与观察部位活检所得的病理组织学改变进行比较分析。结果 146例患者中放大内镜检出息肉172枚,经0.2%的靛胭脂染色放大后又发现0.1～0.5cm大小的息肉84枚,共计息肉样病变256枚。染色放大内镜可明显提高息肉病变的检出率。各种腺管开口分型的病理诊断结果构成差异有显著性,Ⅰ～Ⅴ分型与病变严重程度之间呈明显正相关。染色放大内镜对大肠肿瘤性病变诊断符合率89.5%、敏感性82.2%、特异性92.3%,放大内镜诊断符合率71.5%、敏感性61.8%、特异性77.9%,染色放大内镜对大肠肿瘤性疾病诊断与放大内镜相比差异具有统计学意义（P〈0.01）。结论染色放大内镜对大肠肿瘤的诊断优于放大内镜,能够提高大肠癌的早期诊断率,从而为大肠癌及其癌前病变的内镜下正确处理提供快速而准确的依据。     

Magnetic Resonance Imaging in diagnosis and follow-up of Crohn's Disease--Is conventional enteroclysis still necessary?

A non-invasive diagnostic modality for differential diagnosis and detection of complications in inflammatory bowel disease (IBD) is desirable as alternative to invasive and troublesome endoscopy and conventional radiological methods. METHODS: 51 patients suspicious of inflammatory bowel disease (bloody diarrhoea, symptoms of stenosis, abdominal pain) were investigated consecutively according to a standardised protocol by magnetic resonance tomography (MRI). Also, endoscopy was performed dependent on clinical presentation. MRI findings were compared to clinical follow-up, percutaneous ultrasonography (US), endoscopy, and surgical findings. RESULTS: MRI confirmed diagnosis of Crohn's disease (CD) in more than 90 % of cases. In case of distinct lesions, all of these were detected by MRI in the small bowel and colon. Discreet inflammatory lesions were not seen regularly. Numerous findings in endoscopically inaccessible bowel segments were described by MRI, extraintestinal lesions (conglomerate, abscess, fistulae) were detected accurately. Altogether, MRI was superior to abdominal ultrasonography. CONCLUSION: In patients with distinct inflammatory bowel disease, and in detection of complications (abscess, fistulae), MRI appears as versatile, non-invasive and accurate diagnostic instrument with therapeutical consequence. Endoscopy remains method of first choice for detection of discreet lesions and for histopathological diagnosis.     

Narrow band imaging and multiband imaging

NBI and MBI may enhance the diagnosis and characterization of mucosal lesions in the GI tract, particularly as adjunctive techniques to magnification endoscopy. Standardization of image characterization, further image-to-pathology correlation and validation, and the impact of these technologies on patient outcomes are necessary before endorsing the use of NBI and MBI in the routine practice of GI endoscopy.     

Colonic lesions in patients undergoing small bowel capsule endoscopy

Purpose  

Capsule endoscopy by enabling direct visualization of small bowel mucosa has conquered the last frontier of diagnostic endoscopy. However, its ability to simultaneously detect colonic lesions has not been evaluated. This study was done to evaluate frequency of detection of colonic abnormalities in patients undergoing small bowel capsule endoscopy and its impact on the clinical management.     

Upper gastrointestinal endoscopy in the pediatric patient.

The value of upper gastrointestinal endoscopy in adults is well established. This study of 50 children demonstrates that upper gastrointestinal endoscopy can be performed safely and effectively in this age group without general anesthesia. Endoscopy appears more sensitive than radiology in the detection not only of superficial mucosal lesions, but of gastric and duodenal ulcers as well.     

DIAGNOSIS OF COLONIC ADENOMAS BY NEW AUTOFLUORESCENCE IMAGING SYSTEM: A PILOT STUDY

Detection and removal of adenoma by colonoscopy is an important means of preventing cancer. Autofluorescence endoscopy can visualize flat or isochromatic tumor that was not detectable by white light endoscopy by the difference in tissue fluorescence properties. Recently, a new autofluorescence imaging system (AFI, Olympus Medical Systems) using a combination of autofluorescence and reflection imaging has been developed. The purpose of the present paper was to investigate its feasibility in detection of colonic adenoma in a clinical setting. A total of 64 patients were randomly assigned to AFI or white light groups, and the distal sigmoid colon and the rectum was observed under autofluorescence or white light followed by the other mode of observation by a different endoscopist. The diagnostic ability of each method for detection of neoplasms was compared in relation to the histology as a reference standard. Sensitivity and specificity of AFI for detection of neoplastic polyps was 84% and 60%, respectively, and were similar to those of white light colonoscopy: 90% and 64%. Conventional colonoscopy overlooked more flat lesions including one adenocarcinoma. AFI has the potential to detect more flat lesions but efficacy was unable to be demonstrated in the restricted population. Further investigations are needed to determine optimum usage.     

Quest for the best endoscopic imaging modality for computer-assisted colonic polyp staging

BACKGROUND It was shown in previous studies that high definition endoscopy, high magnification endoscopy and image enhancement technologies, such as chromoendoscopy and digital chromoendoscopy [narrow-band imaging(NBI), iScan] facilitate the detection and classification of colonic polyps during endoscopic sessions. However, there are no comprehensive studies so far that analyze which endoscopic imaging modalities facilitate the automated classification of colonic polyps. In this work, we investigate the impact of endoscopic imaging modalities on the results of computer-assisted diagnosis systems for colonic polyp staging.AIM To assess which endoscopic imaging modalities are best suited for the computerassisted staging of colonic polyps.METHODS In our experiments, we apply twelve state-of-the-art feature extraction methods for the classification of colonic polyps to five endoscopic image databases of colonic lesions. For this purpose, we employ a specifically designed experimental setup to avoid biases in the outcomes caused by differing numbers of images per image database. The image databases were obtained using different imaging modalities. Two databases were obtained by high-definition endoscopy in combination with i-Scan technology(one with chromoendoscopy and one without chromoendoscopy). Three databases were obtained by highmagnification endoscopy(two databases using narrow band imaging and one using chromoendoscopy). The lesions are categorized into non-neoplastic and neoplastic according to the histological diagnosis.RESULTS Generally, it is feature-dependent which imaging modalities achieve high results and which do not. For the high-definition image databases, we achieved overall classification rates of up to 79.2% with chromoendoscopy and 88.9% without chromoendoscopy. In the case of the database obtained by high-magnification chromoendoscopy, the classification rates were up to 81.4%. For the combination of high-magnification endoscopy with NBI, results of up to 97.4% for one database and up to 84% for the other were achieved. Non-neoplastic lesions were classified more accurately in general than non-neoplastic lesions. It was shown that the image recording conditions highly affect the performance of automated diagnosis systems and partly contribute to a stronger effect on the staging results than the used imaging modality.CONCLUSION Chromoendoscopy has a negative impact on the results of the methods. NBI is better suited than chromoendoscopy. High-definition and high-magnification endoscopy are equally suited.     

Capsule endoscopy： Current status in obscure gastrointestinal bleeding

Capsule endoscopy (CE) is a safe, non invasive diagnostic modality for the evaluation of small bowel lesions. Obscure gastrointestinal bleeding (OGIB) is one of the most important indications of capsule endoscopy. Capsule endoscopy has a very high diagnostic yield especially if the bleeding is ongoing. This technique appears to be superior to other techniques for the detection of suspected lesions and the source of bleeding. Capsule endoscopy has been shown to change the outcome in patients with obscure gastrointestinal (GI) bleed.     

Molecular imaging: interaction between basic and clinical science

One of the major proceedings in the field of gastrointestinal endoscopy has been the advent of molecular imaging, which possesses the potential to have a significant effect on the existing diagnostic and therapeutic paradigms. Molecular imaging encompasses different methods that enable the visualization of disease-specific morphologic or functional alterations of the mucosa based on the molecular signature of individual cells. This development has been made possible by advancements in basic science coupled with technological innovations in endoscopy, both facilitating the identification and characterization of mucosal lesions in vivo based on the lesions' molecular composition rather than their morphologic structure alone. Novel studies based on fluorescent antibody imaging pave the road toward clinical translation and give hope for improved diagnosis and targeted therapies in gastrointestinal diseases.     

Early diagnosis of esophageal cancer.

The doubling time of esophageal cancer, as measured by x-ray films, was studied retrospectively. The average doubling time of 19 lesions in 18 cases was 6.7 months, but in three cases the lesions doubled within a month. The developing time of depth of invasion in esophageal cancer in 19 lesions were: from mucosa to submucosa, 16 +/- 7.8 months; submucosa to advanced adventitia, 6.6 +/- 3.8 months; mucosa to advanced adventitia, 21.1 +/- 6.8 months. Lugol-staining endoscopy was effective in detecting not only lesions but also margin lines. Capsulated brushing cytology is also effective and the diagnostic rate was 94.5% in total, and 84.4% in superficial cancer. For early detection of esophageal cancer it is most desirable to have examinations once every six months and a combination of these three methods is recommended.     

Improving visualization techniques by narrow band imaging and magnification endoscopy

Endoscopy plays an important role in the early detection of gastrointestinal tract neoplasms. Using conventional white light or dye-based image enhanced endoscopy, it has been difficult to assess pre-malignant and early neoplastic lesions precisely. However, narrow band imaging (NBI) dramatically improves the detection of these lesions, particularly in combination with magnifying endoscopy. This allows the endoscopist to accomplish accurate diagnosis. Such enhanced detection of pre-malignant and early neoplastic lesions in the gastrointestinal tract should allow better targeting of biopsy, improved and more appropriate treatment, and thereby contribute to optimal quality of life and patient survival.