Narrow band imaging with magnification for the diagnosis of lesions in the upper gastrointestinal tract

Endoscopy plays an important role in the diagnosis and management of gastrointestinal(GI)tract disorders.Chromoendoscopy has proven to be superior to white light endoscopy for early detection of various GI lesions.This has however been fraught with problems.The use of color stains,time taken to achieve an effect and the learning curve associated with the technique has been some of the pitfalls.Narrow band imaging(NBI)particularly in combination with magnifying endoscopy may allow the endoscopist to accomplish a fairly accurate diagnosis with good histological correlation similar to results achieved with chromoendoscopy.Such enhanced detection of pre-malignant and early neoplastic lesions in the gastrointestinal tract should allow better targeting of biopsies and could ultimately prove to be cost effective.Various studies have been done demonstrating the utility of this novel technology.This article will review the impact of NBI in the diagnosis of upper gastrointestinal tract disorders.     

Photodiagnostic techniques for the endoscopic detection of premalignant gastrointestinal lesions

Considerable attention is given to the clinical diagnosis of gastrointestinal (GI) malignancies as they remain the second leading cause of cancer‐associated deaths in developed countries. Detection and intervention at an early stage of preneoplastic development significantly improve patient survival. High‐risk assessment of asymptomatic patients is currently performed by strict endoscopic surveillance biopsy protocols aimed at early detection of dysplasia and malignancy. However, poor sensitivity associated with frequent surveillance programs incorporating conventional screening tools, such as white light endoscopy and multiple random biopsy, is a significant limitation. Recent advances in biomedical optics are illuminating new ways to detect premalignant lesions of the GI tract with endoscopy. The present review presents a summary report on the newest developments in modern GI endoscopy, which are based on novel optical endoscopic techniques: fluorescence endoscopic imaging and spectroscopy, Raman spectroscopy, light scattering spectroscopy, optical coherence tomography, chromoendoscopy, confocal fluorescence endoscopy and immunofluorescence endoscopy. Relying on the interaction of light with tissue, these ‘state‐of‐the‐art’ techniques potentially offer an improved strategy for diagnosis of early mucosal lesions by facilitating targeted excisional biopsies. Furthermore, the prospects of real‐time ‘optical biopsy’ and improved staging of lesions may significantly enhance the endoscopist's ability to detect subtle preneoplastic mucosal changes and lead to curative endoscopic ablation of these lesions. Such advancements within this specialty will be rewarded in the long term with improved patient survival and quality of life.     

Opinion: How to manage subepithelial lesions of the upper gastrointestinal tract?

Subepithelial lesions (SELs) in the upper gastrointestinal (GI) tract are relatively frequent findings in patients undergoing an upper GI endoscopy. These tumors, which are located below the epithelium and out of reach of conventional biopsy forceps, may pose a diagnostic challenge for the gastroenterologist, especially when SELs are indeterminate after endoscopy and endoscopic ultrasound (EUS). The decision to proceed with further investigation should take into consideration the size, location in the GI tract, and EUS features of SELs. Gastrointestinal stromal tumor (GIST) is an example of an SEL that has a well-recognized malignant potential. Unfortunately, EUS is not able to absolutely differentiate GISTs from other benign hypoechoic lesions from the fourth layer, such as leiomyomas. Therefore, EUS-guided fine needle aspiration (EUS-FNA) is an important tool for correct diagnosis of SELs. However, small lesions (size < 2 cm) have a poor diagnostic yield with EUS-FNA. Moreover, studies with EUS-core biopsy needles did not report higher rates of histologic and diagnostic yields when compared with EUS-FNA. The limited diagnostic yield of EUS-FNA and EUS-core biopsies of SELs has led to the development of more invasive endoscopic techniques for tissue acquisition. There are initial studies showing good results for tissue biopsy or resection of SELs with endoscopic submucosal dissection, suck-ligate-unroof-biopsy, and submucosal tunneling endoscopic resection.     

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.     

A REVIEW OF CURRENT CLINICAL APPLICATIONS OF UPPER GASTROINTESTINAL ZOOM ENDOSCOPY

Current clinical applications of upper gastrointestinal (GI) zoom endoscopy were reviewed. The objective of upper GI zoom endoscopy has been the diagnosis of neoplastic lesions as well as the diagnosis of minute inflammatory mucosal change. The target organ and pathology of the neoplastic lesions have been squamous cell carcinoma in the oro‐ and hypo‐pharynx and in the esophagus; intestinal metaplasia, dysplasia, and adenocarcinoma in Barrett's esophagus; and adenocarcinoma in the stomach. For analyzing the magnified endoscopic findings, there were two different basic principles (mucosal microstructural change and subepithelial microvascular changes). Overall diagnostic accuracy for diagnosing a neoplastic lesion was above 80% throughout the upper GI tract. Although the diagnostic accuracy of the zoom endoscopy technique seems to be superior to that of the ordinary endoscopy technique alone, the continuous efforts to establish standardized guidelines and procedures are mandatory in order to lead to the routine use of upper GI zoom endoscopy in clinical practice.     

Endoscopic detection of early lower gastrointestinal cancer

The prognosis for patients with malignancies of the lower gastrointestinal tract is strictly dependent on early detection of premalignant and malignant lesions. What should an ideal screening and surveillance colonoscopy be able to accomplish? The technique should allow detection of large but also discrete mucosal alterations. Ideally, endoscopic discrimination between neoplastic and non-neoplastic lesions would be possible during the ongoing procedure. At present, endoscopy can be performed with powerful new endoscopes. Comparable to the rapid development in chip technology, the optical features of the newly designed endoscopes offer resolutions, which allow new surface details to be seen. In conjunction with chromoendoscopy, the newly discovered tool video colonoscopy is much easier and more impressive today than with the previously used fibre-optic endoscopes. Recently, new endoscopic technologies such as narrow band imaging, endocytoscopy, or confocal laser endoscopy have allowed the discovery of a whole new world of image details which will surely improve the diagnostic yield in the field of early malignancies. This review summarises newly available technologies and clinical data about the diagnosis of early lower gastrointestinal cancers.     

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)     

The future of endoscopy: Advances in endoscopic image innovations

The latest state of the art technological innovations have led to a palpable progression in endoscopic imaging and may facilitate standardisation of practice. One of the most rapidly evolving modalities is artificial intelligence with recent studies providing real-time diagnoses and encouraging results in the first randomised trials to conventional endoscopic imaging. Advances in functional hypoxia imaging offer novel opportunities to be used to detect neoplasia and the assessment of colitis. Three-dimensional volumetric imaging provides spatial information and has shown promise in the increased detection of small polyps. Studies to date of self-propelling colonoscopes demonstrate an increased caecal intubation rate and possibly offer patients a more comfortable procedure. Further development in robotic technology has introduced ex vivo automated locomotor upper gastrointestinal and small bowel capsule devices. Eye-tracking has the potential to revolutionise endoscopic training through the identification of differences in experts and non-expert endoscopist as trainable parameters. In this review, we discuss the latest innovations of all these technologies and provide perspective into the exciting future of diagnostic luminal endoscopy.     

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.     

Magnifying endoscopy in upper gastroenterology for assessing lesions before completing endoscopic removal

Any prognosis of gastrointestinal (GI) cancer is closely related to the stage of the disease at diagnosis. Endoscopic submucosal dissection (ESD) and en bloc endoscopic mucosal resection (EMR) have been performed as curative treatments for many early-stage GI lesions in recent years. The technologies have been widely accepted in many Asian countries because they are minimally invasive and supply thorough histopathologic evaluation of the specimens. However, before engaging in endoscopic therapy, an accurate diagnosis is a precondition to effecting the complete cure of the underlying malignancy or carcinoma in situ. For the past few years, many new types of endoscopic techniques, including magnifying endoscopy with narrow-band imaging (ME-NBI), have emerged in many countries because these methods provide a strong indication of early lesions and are very useful in determining treatment options before ESD or EMR. However, to date, there is no comparable classification equivalent to "Kudo's Pit Pattern Classification in the colon", for the upper GI, there is still no clear internationally accepted classification system of magnifying endoscopy. Therefore, in order to help unify some viewpoints, here we will review the defining optical imaging characteristics and the current representative classifications of microvascular and microsurface patterns in the upper GI tract under ME-NBI, describe the accurate relationship between them and the pathological diagnosis, and their clinical applications prior to ESD or en bloc EMR. We will also discuss assessing the differentiation and depth of invasion, defying the lateral spread of involvement and targeting biopsy in real time.     

Autofluorescence imaging endoscopy for screening of esophageal squamous mucosal high-grade neoplasia: a phase II study

Background and Aim: Few prospective studies examining the efficacy of autofluorescence imaging (AFI) screening for esophageal cancer have been reported. This study aimed to investigate the diagnostic value of AFI endoscopy for the screening of squamous mucosal high‐grade neoplasia of the esophagus, performed by experienced and less‐experienced endoscopists. Methods: Patients with a history of esophageal neoplasia or head and neck cancer underwent AFI endoscopic screening, followed by chromoendoscopy using iodine staining as the reference standard. The primary outcome was the sensitivity of AFI for detecting new squamous mucosal high‐grade neoplasias. The secondary outcome was the positive predictive value (PPV) of AFI. Results: Of a total 364 patients who underwent endoscopic examination, 43 new mucosal high‐grade neoplasias were detected. The sensitivities of AFI in the experienced and less‐experienced endoscopist groups were 71% (95% confidence interval [CI]: 55–87%) and 50% (95% CI: 32–68%), respectively. The PPV of AFI in the experienced and the less‐experienced endoscopist groups were 25% (95% CI: 16–34%) and 26% (95% CI: 15–37%), respectively. The sensitivity of AFI in lesions ≤ 10 mm (31%, 5/16 lesions) was significantly lower than that in lesions > 10 mm (78%, 21/27 lesions) (P = 0.003). Conclusions: The sensitivity of AFI for the detection of new squamous mucosal high‐grade neoplasias, and its PPV, were both low. Based on these results, a randomized study to compare AFI with standard techniques is not justified.     

Autofluorescence imaging and magnification endoscopy

It is well known that angiogenesis is critical in the transition from premalignant to malignant lesions.Consequently,early detection and diagnosis based on morphological changes to the microvessels are crucial.In the last few years,new imaging techniques which utilize the properties of light-tissue interaction have been developed to increase early diagnosis of gastrointestinal(GI) tract neoplasia.We analyzed several red-flag endoscopic techniques used to enhance visualization of the vascular pattern of pren...     

Esophageal squamous cell carcinoma - precursor lesions and early diagnosis

Squamous cell carcinoma of the esophagus (SCCE) carries a poor prognosis due to late diagnosis.Early detection is highly desirable,since surgical and endoscopic resection offers the only possible cure for esophageal cancer.Population screening should be undertaken in high risk areas,and in low or moderate risk areas for people with risk factors (alcoholics,smokers,mate drinkers,history of head and neck cancer,achalasia and lye stricture of the esophagus).Esophageal balloon cytology is an easy and inexpensive sampling technique,but the current methods are insufficient for primary screening due to sampling errors.Conventional endoscopy with biopsy remains the standard procedure for the identification of pre-malignant and early malignant changes in esophageal mucosa and endoscopic detection.It may be enhanced by several techniques such as dye and optic chromoendoscopy,magnifying endoscopy,and optical-based spectroscopic and imaging modalities.Since more than 80% of SCCE deaths occur in developing countries,where expensive techniques such as narrow band imaging (NBI) and autofluorescence imaging are unavailable,the most cost-effective tool for targeting biopsies may be Lugol dye chromoendoscopy,since it is easy,accurate,inexpensive and available worldwide.In ideal conditions,or in developed countries,is it reasonable to think that optimal detection will require a combination of techniques,such as the combination of Lugol’s chromoendoscopy and NBI to identify esophageal areas that require further characterization by a high resolution technique.The efficacy and cost-effectiveness will determine whether these modalities will become part of standard endoscopy practice.     

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.     

Ultrathin endoscopy for gastrointestinal strictures

Background and Aim: The assessment and treatment of advanced gastrointestinal (GI) strictures, which are defined as the inability to pass through the strictured segment with standard endoscopes, might require radiological work‐up, repeated endoscopies and surgery. The aim of the present study was to assess the role of ultrathin endoscopy (UTE) for the evaluation and treatment of advanced GI strictures. Methods: Patients in whom an initial diagnostic upper or lower endoscopy attempt was incomplete because of a tight stricture underwent a second procedure with a UTE (5.9 mm diameter) in the same session. An interventional endoscopic therapy was also carried out according to the etiology and nature of the stricture using the same UTE. Diagnostic and therapeutic outcomes were recorded and followed up prospectively. The study was conducted in a tertiary endoscopy center. Results: During a one and half year study period, 62 patients (51 at upper and 11 at lower endoscopy) were detected with advanced GI stricture among 8456 diagnostic upper and 3815 lower endoscopy patients. A complete endoscopic examination was successful with UTE in 40 (78%) patients with upper and in nine patients (82%) with lower GI strictures. An interventional procedure was also carried out in 16 patients with the assistance of UTE. Conclusion: UTE is a useful tool for the evaluation of patients with advanced GI strictures. It provides a complete diagnostic endoscopy in most patients and gives an opportunity for therapeutic endoscopic procedures.     

Endoscopic resection of superficial gastrointestinal tumors

Therapeutic endoscopy plays a major role in the management of gastrointestinal （GI） neoplasia. Its indications can be generalized into four broad categories; to remove or obliterate neoplastic lesion, to palliate malignant obstruction, or to treat bleeding. Only endoscopic resection allows complete histological staging of the cancer, which is critical as it allows stratification and refinement for further treatment. Although other endoscopic techniques, such as ablation therapy, may also cure early GI cancer, they can not provide a definitive pathological specimen. Early stage lesions reveal low frequency of lymph node metastasis which allows for less invasive treatments and thereby improving the quality of life when compared to surgery. Endoscopic mucosal resection （EMR） and endoscopic submucosal dissection （ESD） are now accepted worldwide as treatment modalities for early cancers of the GI tract.     

The compactEASIE is a feasible training model for endoscopic novices: A prospective randomised trial

BACKGROUND: The objective benefit of a training using the compact Erlangen Active Simulator for Interventional Endoscopy-simulator was demonstrated in two prospective educational trials (New York, France). The present study analysed whether endoscopic novices are able to reach a comparable level of endoscopic skills as in the above-described projects. METHODS: Twenty-seven endoscopic novices (medical students, first year residents) were enrolled in this prospective, randomised trial. The compact Erlangen Active Simulator for Interventional Endoscopy-simulator with an upper GI-organ package and blood perfusion system was used as a training tool. Basic evaluation of endoscopic skills was performed after a practical and theoretical course in diagnostic upper GI endoscopy followed by a stratified randomisation according to the rating in endoscopic skills into intensive (n=14) and control group (n=13). The intensive group was trained 12 times every second week over 7 months in 4 endoscopic disciplines (manual skills, injection therapy, haemoclip, band ligation) by skilled endoscopist (three trainees/simulator). Assessment was performed (single steps/overall) using an analogue scale from 1 to 10 (1=worst, 10=optimal performance) by expert tutors. The control group was not trained. Blinded final evaluation of all participants was performed in January 2003. RESULTS: We observed in all techniques applied a significant improvement of endoscopic skills and of the performance time in the intensive group compared to the control group (p<0.001). The comparison with the previous projects showed that the intensively trained novices achieved comparable levels of performance to the GI fellows in the New York and France Project (at least 80% of the median score in three out of four techniques). CONCLUSION: Endoscopic novices acquired notable skills in interventional endoscopy in the simulator by an intensive, periodical training using the compactEASIE.     

Potential contribution of novel imaging modalities in non-erosive reflux disease

Non-erosive reflux disease (NERD) is the most frequent endoscopic finding in patients with gastro-oesophageal reflux disease (GORD). Conventional white light endoscopy is an insufficient tool for diagnosing subtle changes of the oesophageal mucosa in patients with NERD. This review will discuss the diagnostic approach and endoscopic features of novel endoscopic imaging techniques such as magnification endoscopy, chromoendoscopy, narrow band imaging (NBI) and confocal laser endomicroscopy (CLE) for patients with this disorder. Magnification endoscopy alone or in combination with chromoendoscopy offers the chance for an improved detection of subtle findings in NERD. However, subtle changes such as punctuate erythema above the Z-line, pinpoint vessels, triangular indentations and other findings show a substantial inter- and intra-observer variability with unacceptably low kappa values for justifying their use as a diagnostic criterion for NERD. NBI and endomicroscopy are fascinating new tools, but access to these novel modalities in clinical practice is limited and the area to be examined is small, which makes it very time-consuming to examine the entire distal oesophagus. It remains to be proven in crossover, randomised trials that these new imaging modalities may represent a significant improvement over standard endoscopy for the diagnosis of NERD.     

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.     

Magnifying endoscopy in upper gastrointestinal tract]

For the diagnosis of upper gastrointestinal (GI) lesions, magnification method is usually used in conjunction with chromoscopy, enabling the endoscopist to view subtle mucosal patterns in exquisite detail. Recently published datas have shown that magnifying endoscopy might be a valuable adjunct for the diagnosis, detection, and characterization of inflammatory and neoplastic lesions of the upper GI tract. It is also proven to be an useful surveillance protocol in identifying dysplastic epithelium or early cancer within a segment of Barrett's esophagus. Possible indications for magnifying endoscopy in upper GI tract include screening and surveillance of Barrett's esophagus, defining the extent of esophageal and gastric adenocarcinoma, detecting synchronous/metachronous gastric and esophageal cancers, diagnosing Helicobacter pylori infection, and recognizing minimal mucosal changes in gastroesophageal reflux disease. By grading the quality of evidence for the currently published trials, it is clear that the majority are case series, case reports, and/or observational studies without randomization, control, or blinding. Moreover, other evidence-based criteria such as independent, blind comparisons of magnifying endoscopy with a standard method which evaluates this technology in an appropriate spectrum of patients to whom the test may be applicable, and standardizing methodology would be crucial before magnifying endoscopy becomes a standard procedure in clinical practice. In the future, a uniform classification system for staining and magnifying patterns should be devised and observer agreement should be tested. Futher studies then could be performed based upon consistent, validated, and standardized terminologies and criteria.