Chromoendoscopy and narrow-band imaging compared with high-resolution magnification endoscopy in Barrett's esophagus

Computer-aided diagnosis improves characterization of Barrett's neoplasia by general endoscopists (with video)

BACKGROUND AND AIMS

Characterization of visible abnormalities in patients with Barrett's esophagus (BE) can be challenging, especially for inexperienced endoscopists. This results in suboptimal diagnostic accuracy and poor interobserver agreement. Computer-aided diagnosis (CADx) systems may assist endoscopists. We aimed to develop, validate, and benchmark a CADx system for BE neoplasia.

METHODS

The CADx system received pretraining with ImageNet and then consecutive domain-specific pretraining with GastroNet, which includes 5 million endoscopic images. It was subsequently trained and internally validated using 1758 narrow-band imaging (NBI) images of early BE neoplasia (352 patients) and 1838 NBI images of nondysplastic BE (173 patients) from 8 international centers. CADx was tested prospectively on corresponding image and video test sets with 30 cases (20 patients) of BE neoplasia and 60 cases (31 patients) of nondysplastic BE. The test set was benchmarked by 44 general endoscopists in 2 phases (phase 1, no CADx assistance; phase 2, with CADx assistance). Ten international BE experts provided additional benchmark performance.

RESULTS

Stand-alone sensitivity and specificity of the CADx system were 100% and 98% for images and 93% and 96% for videos, respectively. CADx outperformed general endoscopists without CADx assistance in terms of sensitivity (P = .04). Sensitivity and specificity of general endoscopists increased from 84% to 96% and 90% to 98% with CAD assistance (P < .001). CADx assistance increased endoscopists' confidence in characterization (P < .001). CADx performance was similar to that of the BE experts.

CONCLUSIONS

CADx assistance significantly increased characterization performance of BE neoplasia by general endoscopists to the level of expert endoscopists. The use of this CADx system may thereby improve daily Barrett surveillance.

Expert assessment of infiltration depth and recommendation of endoscopic resection technique in early Barrett cancer

BACKGROUND

Early Barrett cancer can be curatively treated by endoscopic resection. The choice of the resection technique, however-endoscopic mucosal resection (EMR) or submucosal dissection (ESD)-largely depends on the assumed infiltration depth as judged by the endoscopist. However, the accuracy of endoscopic diagnosis of the degree of cancer infiltration is not known.

METHODS

Three to four high-quality images (both in overview and close-up) from 202 of early Barrett esophagus cancer cases (82% men, mean age 66.9 years) were selected from our endoscopy database (73.3% stage T1a and 26.7% in stage T1b). Images were shown to 9 Barrett esophagus experts, with patients' clinical data (age, sex, Barrett esophagus length) and biopsy results. The experts were asked to predict infiltration depth (T1b vs. T1a), and to suggest the appropriate endoscopic resection technique (EMR or ESD, or surgery). Interobserver variability (kappa values) was also determined for these parameters.

RESULTS

Overall positive (PPV) and negative predictive values (NPV) to diagnose T1b versus T1a infiltration were 40.7% (95% CI: 36.7, 44.8) and 79.8% (95% CI: 77.5, 81.9), respectively; kappa value was 0.41. Paris classification (kappa 0.51) and suggested treatment also varied between experts. In a post hoc analysis, only the correlation between lesions classified as invisible or flat according to the Paris classification (IIB; 25% of all cases) and the suggested resection technique was better: In this subgroup, EMR was recommended in >80% of cases, with a high complete (basal R0) resection rate (mean of 88.1%).

CONCLUSIONS

Precise endoscopic distinction between mucosal and submucosal involvement of Barrett esophagus cancer by experts as a basis for choosing the resection technique has limited predictive values and high interobserver variability. It seems that mainly invisible/flat lesions may result in good resection outcomes when treated by EMR, but this stratification strategy has to be assessed in further studies.

A computer-assisted algorithm for narrow-band imaging-based tissue characterization in Barrett's esophagus

BACKGROUND AND AIMS

The endoscopic evaluation of narrow-band imaging (NBI) zoom imagery in Barrett's esophagus (BE) is associated with suboptimal diagnostic accuracy and poor interobserver agreement. Computer-aided diagnosis (CAD) systems may assist endoscopists in the characterization of Barrett's mucosa. Our aim was to demonstrate the feasibility of a deep-learning CAD system for tissue characterization of NBI zoom imagery in BE.

METHODS

The CAD system was first trained using 494,364 endoscopic images of general endoscopic imagery. Next, 690 neoplastic BE and 557 nondysplastic BE (NDBE) white-light endoscopy overview images were used for refinement training. Subsequently, a third dataset of 112 neoplastic and 71 NDBE NBI zoom images with histologic correlation was used for training and internal validation. Finally, the CAD system was further trained and validated with a fourth, histologically confirmed dataset of 59 neoplastic and 98 NDBE NBI zoom videos. Performance was evaluated using fourfold cross-validation. The primary outcome was the diagnostic performance of the CAD system for classification of neoplasia in NBI zoom videos.

RESULTS

The CAD system demonstrated accuracy, sensitivity, and specificity for detection of BE neoplasia using NBI zoom images of 84%, 88%, and 78%, respectively. In total, 30,021 individual video frames were analyzed by the CAD system. Accuracy, sensitivity, and specificity of the video-based CAD system were 83% (95% confidence interval [CI], 78%-89%), 85% (95% CI, 76%-94%), and 83% (95% CI, 76%-90%), respectively. The mean assessment speed was 38 frames per second.

CONCLUSION

We have demonstrated promising diagnostic accuracy of predicting the presence/absence of Barrett's neoplasia on histologically confirmed unaltered NBI zoom videos with fast corresponding assessment time.

Advanced Imaging and Sampling in Barrett's Esophagus: Artificial Intelligence to the Rescue?

Because the current Barrett's esophagus (BE) surveillance protocol suffers from sampling error of random biopsies and a high miss-rate of early neoplastic lesions, many new endoscopic imaging and sampling techniques have been developed. None of these techniques, however, have significantly increased the diagnostic yield of BE neoplasia. In fact, these techniques have led to an increase in the amount of visible information, yet endoscopists and pathologists inevitably suffer from variations in intra- and interobserver agreement. Artificial intelligence systems have the potential to overcome these endoscopist-dependent limitations.

Measuring Quality in Barrett's Esophagus: Time to Embrace Quality Indicators

Endoscopic eradication therapy is a safe and effective therapy that has revolutionized the management of patients with Barrett's esophagus (BE)-related neoplasia. Despite this, there remains significant heterogeneity in clinical practice with consequent variation in patient outcomes. The aim of this article was to align consensus statements based on the best available evidence and expert opinion from the United States and United Kingdom to develop robust and measurable quality indicators that help to ensure patients with BE-related neoplasia receive the highest possible quality of care uniformly.

Advanced endoscopic imaging for detecting and guiding therapy of early neoplasias of the esophagus

Esophageal cancers, largely adenocarcinoma in Western countries and squamous cell cancer in Asia, present a significant burden of disease and remain one of the most lethal of cancers. Key to improving survival is the development and adoption of new imaging modalities to identify early neoplastic lesions, which may be small, multifocal, subsurface, and difficult to detect by standard endoscopy. Such advanced imaging is particularly relevant with the emergence of ablative techniques that often require multiple endoscopic sessions and may be complicated by bleeding, pain, strictures, and recurrences. Assessing the specific location, depth of involvement, and features correlated with neoplastic progression or incomplete treatment may optimize treatments. While not comprehensive of all endoscopic imaging modalities, we review here some of the recent advances in endoscopic luminal imaging, particularly with surface contrast enhancement using virtual chromoendoscopy, highly magnified subsurface imaging with confocal endomicroscopy, optical coherence tomography, elastic scattering spectroscopy, angle-resolved low-coherence interferometry, and light scattering spectroscopy. While there is no single ideal imaging modality, various multimodal instruments are also being investigated. The future of combining computer-aided assessments, molecular markers, and improved imaging technologies to help localize and ablate early neoplastic lesions shed hope for improved disease outcome.

Towards screening Barrett's oesophagus: current guidelines, imaging modalities and future developments

Barrett's oesophagus is the only known precursor to oesophageal adenocarcinoma (OAC). Although guidelines on the screening and surveillance exist in Barrett's oesophagus, the current strategies are inadequate. Oesophagogastroduodenoscopy (OGD) is the gold standard method in screening for Barrett's oesophagus. This invasive method is expensive with associated risks negating its use as a current screening tool for Barrett's oesophagus. This review explores current definitions, epidemiology, biomarkers, surveillance, and screening in Barrett's oesophagus. Imaging modalities applicable to this condition are discussed, in addition to future developments. There is an urgent need for an alternative non-invasive method of screening and/or surveillance which could be highly beneficial towards reducing waiting times, alleviating patient fears and reducing future costs in current healthcare services. Vibrational spectroscopy has been shown to be promising in categorising Barrett's oesophagus through to high-grade dysplasia (HGD) and OAC. These techniques need further validation through multicentre trials.

Challenges to diagnostic standardization of Barrett's esophagus in Asia

Barrett's esophagus (BE), a premalignant condition of the lower esophagus, is increasingly prevalent in Asia. However, endoscopic and histopathological criteria vary widely between studies across Asia, making it challenging to assess comparability between geographical regions. Furthermore, guidelines from various societies worldwide provide differing viewpoints and definitions, leading to diagnostic challenges that affect prognostication of the condition. In this review, the authors discuss the controversies surrounding the diagnosis of BE, particularly in Asia. Differences between guidelines worldwide are summarized with further discussion regarding various classifications of BE used, different definitions of gastroesophageal junction used across geographical regions and the clinical implications of intestinal metaplasia in the setting of BE. Although many guidelines recommend the Seattle protocol as the preferred approach regarding dysplasia surveillance in BE, some limitations exist, leading to poor adherence. Newer technologies, such as acetic acid-enhanced magnification endoscopy, narrow band imaging, Raman spectroscopy, molecular approaches and the use of artificial intelligence appear promising in addressing these problems, but further studies are required before implementation into routine clinical practice. The Asian Barrett's Consortium also outlines its ongoing plans to tackle the challenge of standardizing the diagnosis of BE in Asia.

Differences in colonic crypt morphology of spontaneous and colitis-associated murine models via second harmonic generation imaging to quantify colon cancer development

Background

Colorectal cancer remains the second leading cause of cancer death in the United States, and increased risk in patients with ulcerative colitis (a subset of inflammatory bowel disease) has motivated studies into early markers of dysplasia. The development of clinically translatable multiphoton imaging systems has allowed for the potential of in vivo label-free imaging of epithelial crypt structures via autofluorescence and/or second harmonic generation (SHG). SHG has been used to investigate collagen structures in various types of cancer, though the changes that colorectal epithelial collagen structures undergo during tumor development, specifically colitis-associated tumors, have not been fully investigated.

Methods

This study used two murine models, using A/J mice, one for spontaneous carcinoma and one for colitis-associated carcinoma, to investigate and quantify SHG image features that could potentially inform future study designs of endoscopic multiphoton imaging systems. The spontaneous tumor model comprised a series of six weekly injections of azoxymethane (AOM model). The colitis-associated tumor model comprised a single injection of AOM, followed by cycles of drinking water with dissolved dextran sodium sulfate salt (AOM-DSS model). SHG images of freshly resected murine colon were acquired with a multiphoton imaging system, and image features, such as crypt size, shape and distribution, were quantified using an automated algorithm.

Results

The comparison of quantified features of crypt morphology demonstrated the ability of our quantitative image feature algorithms to detect differences between spontaneous (AOM model) and colitis-associated (AOM-DSS model) murine colorectal tissue specimens. There were statistically significant differences in the mean and standard deviation of nearest neighbor (distance between crypts) and circularity between the Control cohort, AOM and AOM-DSS cohorts. We also saw significance between AOM and AOM-DSS cohorts when calculating nearest neighbor in images acquired at fixed depths.

Conclusion

The results provide insight into the ability of SHG imaging to yield relevant data about the crypt microstructure in colorectal epithelium, specifically the potential to distinguish between spontaneous and colitis-associated murine models using quantification of crypt shape and distribution, informing future design of translational multiphoton imaging systems and protocols.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5639-8) contains supplementary material, which is available to authorized users.

Blue-light imaging has an additional value to white-light endoscopy in visualization of early Barrett's neoplasia: an international multicenter cohort study

BACKGROUND AND AIMS

Endoscopic features of early neoplasia in Barrett's esophagus (BE) are subtle. Blue-light imaging (BLI) may improve visualization of neoplastic lesions. The aim of this study was to evaluate BLI in visualization of Barrett's neoplasia.

METHODS

Corresponding white-light endoscopy (WLE) and BLI images of 40 BE lesions were obtained prospectively and assessed by 6 international experts in 3 assessments. Each assessment consisted of overview and magnification images. Assessments were as follows: assessment 1, WLE only; assessment 2, BLI only; and assessment 3, corresponding WLE and BLI images. Outcome parameters were as follows: (1) appreciation of macroscopic appearance and surface relief (visual analog scale scores); (2) ability to delineate lesions (visual analog scale scores); (3) preferred technique for delineation (ordinal scores); and (4) quantitative agreement on delineations (AND/OR scores).

RESULTS

Experts appreciated BLI significantly better than WLE for visualization of macroscopic appearance (median 8.0 vs 7.0, P < .001) and surface relief (8.0 vs 6.0, P < .001). For both overview and magnification images, experts appreciated BLI significantly better than WLE for ability to delineate lesions (8.0 vs 6.0, P < .001 and 8.0 vs 5.0, P < .001). There was no overall significant difference in AND/OR scores of WLE + BLI when compared with WLE, yet agreement increased significantly with WLE + BLI for cases with a low baseline AND/OR score on WLE, both in overview (mean difference, 0.15; P = .015) and magnification (mean difference, 0.10; P = .01).

CONCLUSIONS

BLI has additional value for visualization of BE neoplasia. Experts appreciated BLI better than WLE for visualization and delineation of BE neoplasia. Quantitative agreement increased significantly when BLI was offered next to WLE for lesions that were hard to delineate with WLE alone. (ISRCTN registry study ID: ISRCTN15916689.).

Endoscopic diagnosis and treatment of esophageal adenocarcinoma: introduction of Japan Esophageal Society classification of Barrett's esophagus

Endoscopic surveillance of Barrett's esophagus has become a foundation of the management of esophageal adenocarcinoma (EAC). Surveillance for Barrett's esophagus commonly involves periodic upper endoscopy with biopsies of suspicious areas and random four-quadrant biopsies. However, targeted biopsies using narrow-band imaging can detect more dysplastic areas and thus reduce the number of biopsies required. Several specific mucosal and vascular patterns characteristic of Barrett's esophagus have been described, but the proposed criteria are complex and diverse. Simpler classifications have recently been developed focusing on the differentiation between dysplasia and non-dysplasia. These include the Japan Esophageal Society classification, which defines regular and irregular patterns in terms of mucosal and vascular shapes. Cancer invasion depth is diagnosed by endoscopic ultrasonography (EUS); however, a meta-analysis of EUS staging of superficial EAC showed favorable pooled values for mucosal cancer staging, but unsatisfactory diagnostic results for EAC at the esophagogastric junction. Endoscopic resection has recently been suggested as a more accurate staging modality for superficial gastrointestinal cancers than EUS. Following endoscopic resection for gastrointestinal cancers, the risk of metastasis can be evaluated based on the histology of the resected specimen. European guidelines describe endoscopic resection as curative for well- or moderately differentiated mucosal cancers without lymphovascular invasion, and these criteria might be extended to lesions invading the submucosa (≤ 500 μm), i.e., to low-risk, well- or moderately differentiated tumors without lymphovascular involvement, and < 3 cm. These criteria were confirmed by a recent study in Japan.

Enhancing the Detection of Barrett Esophagus

In Western countries, the incidence of esophageal adenocarcinoma has increased rapidly in parallel with its premalignant condition, Barrett esophagus (BE). Unlike colonoscopy, endoscopic screening for BE is not currently recommended for all patients; however, surveillance endoscopy is advocated for patients with established BE. Novel imaging and sampling techniques have been developed and investigated for the purpose of improving the detection of Barrett esophagus, dysplasia, and neoplasia. This article discusses several screening and surveillance techniques, including Seattle protocol, chromoendoscopy, electronic chromoendoscopy, wide area transepithelial sampling with 3-dimensional analysis, nonendoscopic sampling devices, and transnasal endoscopy.

Novel Developments in Endoscopic Mucosal Imaging

Endoscopic techniques such as high-definition and optical-chromoendoscopy have had enormous impact on endoscopy practice. Since these techniques allow assessment of most subtle morphological mucosal abnormalities, further improvements in endoscopic practice lay in increasing the detection efficacy of endoscopists. Several new developments could assist in this. First, web based training tools could improve the skills of the endoscopist for enhancing the detection and classification of lesions. Secondly, incorporation of computer aided detection will be the next step to raise endoscopic quality of the captured data. These systems will aid the endoscopist in interpreting the increasing amount of visual information in endoscopic images providing real-time objective second reading. In addition, developments in the field of molecular imaging open opportunities to add functional imaging data, visualizing biological parameters, of the gastrointestinal tract to white-light morphology imaging. For the successful implementation of abovementioned techniques, a true multi-disciplinary approach is of vital importance.

Controversies in Endoscopic Eradication Therapy for Barrett's Esophagus

Advances in endoscopic eradication therapy for Barrett's Esophagus-associated neoplasia have resulted in a significant paradigm shift in the diagnosis and management of this complex disease. A robust body of literature critically evaluating outcomes of resection and ablative strategies has allowed gastroenterologists to make quality, evidence-based decisions for their patients. Despite this progress, there are still many unanswered questions and challenges that remain. Ultimately, identification of a cost-effective screening modality, biomarkers for risk stratification, and strides to eliminate post surveillance endoscopy after endoscopic eradication therapy are essential to reach our long-term goal for eradication of esophageal adenocarcinoma.

Diagnosis and treatment of superficial esophageal cancer

Endoscopy allows for the screening, early diagnosis, treatment and follow up of superficial esophageal cancer. Endoscopic submucosal dissection has become the gold standard for the resection of superficial squamous cell neoplasia. Combinations of endoscopic mucosal resection and radiofrequency ablation are the mainstay of the management of Barrett’s associated neoplasia. However, protruded, non-lifting or large lesions may be better managed by endoscopic submucosal dissection. Novel ablation tools, such as argon plasma coagulation with submucosal lifting and cryoablation balloons, are being developed for the treatment of residual Barrett’s esophagus, since iatrogenic strictures still hamper the development of extensive circumferential resections in the esophagus. Optimal surveillance modalities after endoscopic resection are still to be determined. The assessment of the risk of lymph-node metastases, as well as of the need for additional treatments based on qualitative and quantitative histological criteria, balanced to the patient’s condition, requires a dedicated multidisciplinary team decision process. The need for trained endoscopists, expert pathologists and surgeons, and specialized multidisciplinary meetings underlines the role of expert centers in the management of superficial esophageal cancer.

The Role of Adjunct Imaging in Endoscopic Detection of Dysplasia in Barrett's Esophagus

Advances in imaging technologies have demonstrated promise in early detection of dysplasia and cancer in Barrett's esophagus (BE). Optical chromoendoscopy, dye-based chromoendoscopy, and novel technologies have provided the opportunity to visualize the cellular and subcellular structures. Only narrow-band imaging and acetic acid chromoendoscopy have reached benchmarks for clinical use. Volumetric laser endomicroscopy and molecular imaging are not established for routine use. Best practice in management of BE should be focused on careful endoscopic examination, resection, or ablation of the entire abnormal lesion, as well as the use of available imaging technique that has good diagnostic accuracy.

Evaluation of NinePoint Medical's Nvision VLE device for gastrointestinal applications

INTRODUCTION

The incidence of esophageal adenocarcinoma (EAC) has increased over the last few decades. With a known precursor lesion, Barrett's esophagus, this remains a target for screening and surveillance with the goal of detecting and providing curative treatment for early neoplasia. Areas covered: Current surveillance techniques rely on white light endoscopy and random tissue sampling which is time consuming, costly and prone to sampling error. Volumetric laser endomicroscopy (VLE), a second-generation optical coherence technology, has emerged as an advanced imaging modality with the potential to improve dysplasia detection, surveillance and subsequently prevent esophageal adenocarcinoma. This review will focus on the use of VLE for advanced imaging of Barrett's esophagus and summarize its current and potential uses elsewhere in the GI tract. Expert commentary: NinePoint's VLE imaging device enables imaging of large segments of BE facilitating identification of luminal and subsurface abnormalities that may have otherwise been missed. Its diagnostic accuracy is improving and laser-marking system adds the capacity for accurate VLE-histologic correlation. With the adoption of dysplasia scoring systems that utilize very few VLE imaging features, inexperienced endoscopists will likely be able to pick out areas concerning for dysplasia to target therapy.

Tri-Scan: A Three Stage Color Enhancement Tool for Endoscopic Images

Modern endoscopes play a significant role in diagnosing various gastrointestinal (GI) tract related diseases where the visual quality of endoscopic images helps improving the diagnosis. This article presents an image enhancement method for color endoscopic images that consists of three stages, and hence termed as "Tri-scan" enhancement: (1) tissue and surface enhancement: a modified linear unsharp masking is used to sharpen the surface and edges of tissue and vascular characteristics; (2) mucosa layer enhancement: an adaptive sigmoid function is employed on the R plane of the image to highlight micro-vessels of the superficial layers of the mucosa and submucosa; and (3) color tone enhancement: the pixels are uniformly distributed to create an enhanced color effect to highlight the subtle micro-vessels, mucosa and tissue characteristics. The proposed method is used on a large data set of low contrast color white light images (WLI). The results are compared with three existing enhancement techniques: Narrow Band Imaging (NBI), Fuji Intelligent Color Enhancement (FICE) and i-scan Technology. The focus value and color enhancement factor show that the enhancement level achieved in the processed images is higher compared to NBI, FICE and i-scan images.

Quality Indicators in Endoscopic Ablation for Barrett's Esophagus

OPINION STATEMENT

Barrett's esophagus (BE) is a well-established premalignant condition for esophageal adenocarcinoma (EAC); a cancer that is associated with a poor 5-year survival rate. Several strategies have been explored in the context of reducing the burden of EAC. Endoscopic eradication therapy (EET) is considered the standard of care for the management of patients with BE with dysplasia and early neoplasia; a practice that has been endorsed by all gastroenterology societal guidelines. The effectiveness of EET has been demonstrated in multiple studies and contemporary management includes a combination of endoscopic mucosal resection (EMR) of all visible lesions followed by eradication of the remaining BE using ablative techniques of which radiofrequency ablation (RFA) has the best evidence supporting effectiveness and safety. These techniques are being used increasingly at academic tertiary care centers and community practices. In this era of value-based health care, there is increased focus on the establishment, documentation, and reporting of quality indicators; indicators that are important to physicians, patients, and payers. The purpose of this review is to highlight the current status of quality indicators in EET for the management of patients with BE-related neoplasia and discuss the future steps required to ensure that these quality indicators are uniformly incorporated into practice.

Fluorescein as a topical fluorescent contrast agent for quantitative microendoscopic inspection of colorectal epithelium

Fiber bundle microendoscopic imaging of colorectal tissue has shown promising results, for both qualitative and quantitative analysis. A quantitative image quality control and image feature extraction algorithm was previously designed for quantitative image feature analysis of proflavine-stained ex vivo colorectal tissue. We investigated fluorescein as an alternative topical stain. Images of ex vivo porcine, caprine, and human colorectal tissue were used to compare microendoscopic images of tissue topically stained with fluorescein and proflavine solutions. Fluorescein was shown to be comparable for automated crypt detection, with an average crypt detection sensitivity exceeding 90% using a combination of three contrast limit pairs.

Current Endoscopic Approaches for the Treatment of Barrett Esophagus

Barrett esophagus (BE) is the only identifiable premalignant condition for esophageal adenocarcinoma (EAC), a cancer associated with a poor 5-year survival rate. The stepwise pathologic progression of BE to invasive cancer provides an opportunity to halt progression and potentially decrease incidence and ultimately the morbidity and mortality related to this lethal cancer. Endoscopic eradication therapy (EET) in patients at increased risk of progression to invasive EAC (intramucosal EAC, high-grade dysplasia, and low-grade dysplasia) is a practice that is endorsed by multiple societies and has replaced esophagectomy as the standard of care for these patients. Although the effectiveness, safety, and durability of EET have been demonstrated in several studies, this review addresses the several challenges with EET that need to be considered to optimize patient outcomes. Finally, the critical role of training, competence, and quality indicators in EET are emphasized in this era of value-based health care practice.

Diagnosis and Management of Low-Grade Dysplasia in Barrett's Esophagus: Expert Review From the Clinical Practice Updates Committee of the American Gastroenterological Association

The purpose of this clinical practice update expert review is to define the key principles in the diagnosis and management of low-grade dysplasia (LGD) in Barrett's esophagus patients. The best practices outlined in this review are based on relevant publications, including systematic reviews and expert opinion (when applicable). Practice Advice 1: The extent of Barrett's esophagus should be defined using a standardized grading system documenting the circumferential and maximal extent of the columnar lined esophagus (Prague classification) with a clear description of landmarks and visible lesions (nodularity, ulceration) when present. Practice Advice 2: Given the significant interobserver variability among pathologists, the diagnosis of Barrett's esophagus with LGD should be confirmed by an expert gastrointestinal pathologist (defined as a pathologist with a special interest in Barrett's esophagus-related neoplasia who is recognized as an expert in this field by his/her peers). Practice Advice 3: Expert pathologists should report audits of their diagnosed cases of LGD, such as the frequency of LGD diagnosed among surveillance patients and/or the difference in incidence of neoplastic progression among patients diagnosed with LGD vs nondysplastic Barrett's esophagus. Practice Advice 4: Patients in whom the diagnosis of LGD is downgraded to nondysplastic Barrett's esophagus should be managed as nondysplastic Barrett's esophagus. Practice Advice 5: In Barrett's esophagus patients with confirmed LGD (based on expert gastrointestinal pathology review), repeat upper endoscopy using high-definition/high-resolution white-light endoscopy should be performed under maximal acid suppression (twice daily dosing of proton pump inhibitor therapy) in 8-12 weeks. Practice Advice 6: Under ideal circumstances, surveillance biopsies should not be performed in the presence of active inflammation (erosive esophagitis, Los Angeles grade C and D). Pathologists should be informed if biopsies are obtained in the setting of erosive esophagitis and if pathology findings suggest LGD, or if no biopsies are obtained, surveillance biopsies should be repeated after the anti-reflux regimen has been further intensified. Practice Advice 7: Surveillance biopsies should be performed in a four-quadrant fashion every 1-2 cm with target biopsies obtained from visible lesions taken first. Practice Advice 8: Patients with a confirmed histologic diagnosis of LGD should be referred to an endoscopist with expertise in managing Barrett's esophagus-related neoplasia practicing at centers equipped with high-definition endoscopy and capable of performing endoscopic resection and ablation. Practice Advice 9: Endoscopic resection should be performed in Barrett's esophagus patients with LGD with endoscopically visible abnormalities (no matter how subtle) in order to accurately assess the grade of dysplasia. Practice Advice 10: In patients with confirmed Barrett's esophagus with LGD by expert GI pathology review that persists on a second endoscopy, despite intensification of acid-suppressive therapy, risks and benefits of management options of endoscopic eradication therapy (specifically adverse events associated with endoscopic resection and ablation), and ongoing surveillance should be discussed and documented. Practice Advice 11: Endoscopic eradication therapy should be considered in patients with confirmed and persistent LGD with the goal of achieving complete eradication of intestinal metaplasia. Practice Advice 12: Patients with LGD undergoing surveillance rather than endoscopic eradication therapy should undergo surveillance every 6 months times 2, then annually unless there is reversion to nondysplastic Barrett's esophagus. Biopsies should be obtained in 4-quadrants every 1-2 cm and of any visible lesions. Practice Advice 13: In patients with Barrett's esophagus-related LGD undergoing ablative therapy, radiofrequency ablation should be used. Practice Advice 14: Patients completing endoscopic eradication therapy should be enrolled in an endoscopic surveillance program. Patients who have achieved complete eradication of intestinal metaplasia should undergo surveillance every year for 2 years and then every 3 years thereafter to detect recurrent intestinal metaplasia and dysplasia. Patients who have not achieved complete eradication of intestinal metaplasia should undergo surveillance every 6 months for 1 year after the last endoscopy, then annually for 2 years, then every 3 years thereafter. Practice Advice 15: Following endoscopic eradication therapy, the biopsy protocol of obtaining biopsies in 4 quadrants every 2 cm throughout the length of the original Barrett's esophagus segment and any visible columnar mucosa is suggested. Practice Advice 16: Endoscopists performing endoscopic eradication therapy should report audits of their rates of complete eradication of dysplasia and intestinal metaplasia and adverse events in clinical practice.

Monitoring the premalignant potential of Barrett's oesophagus'

The landscape for patients with Barrett's oesophagus (BE) has changed significantly in the last decade. Research and new guidelines have helped gastroenterologists to better identify those patients with BE who are particularly at risk of developing oesophageal adenocarcinoma. In parallel, developments in endoscopic image enhancement technology and optical biopsy techniques have improved our ability to detect high-risk lesions. Once these lesions have been identified, the improvements in minimally invasive endoscopic therapies has meant that these patients can potentially be cured of early cancer and high-risk dysplastic lesions without the need for surgery, which still has a significant morbidity and mortality. The importance of reaching an accurate diagnosis of BE remains of paramount importance. More work is needed, however. The vast majority of those undergoing surveillance for their BE do not progress towards cancer and thus undergo a regular invasive procedure, which may impact on their psychological and physical well-being while incurring significant cost to the health service. New work that explores cheaper endoscopic or non-invasive ways to identify the at-risk individual provides exciting avenues for research. In future, the diagnosis and monitoring of patients with BE could move away from hospitals and into primary care.

Variation in preparation for gastroscopy: lessons towards safer and better outcomes

OBJECTIVE

To identify the methods employed within the UK practice prior to diagnostic gastroscopy and compare with published guidelines for patients undergoing general anaesthesia.

DESIGN

National Health Service (NHS) endoscopy units were invited to take part in a structured telephone survey to determine the length of time patients are kept nil-by-mouth (NBM) for food and fluids prior to gastroscopy, and whether a preprocedure mucolytic drink was used.

METHODS

212 NHS Trusts providing endoscopy services were identified from the Joint Advisory Group on GI Endoscopy. Trusts were excluded if they were children's hospitals (n=5).

RESULTS

207 NHS Trusts were telephoned. 193 completed the survey (93%), 11 Trusts declined and there was no response from 3 Trusts. 13 separate policies regarding NBM timings were identified. 51 Trusts (21%) used the timings ratified by Surgical and Anaesthetic Societies (6 h NBM for food, 2 h for clear fluid). 135 Trusts (70%) used a policy which starved patients in excess of the standard surgical guidelines. No Trust used a mucolytic drink prior to gastroscopy.

CONCLUSIONS

The survey revealed large variation in NHS Trust's policies regarding the times patients were starved prior to gastroscopy. Results of surgical studies demonstrate increased risk of significant pulmonary aspiration with increased fluid-starvation periods, 68% of NHS endoscopy policy would be deemed excessive by surgical practice. There is no routine use of a mucolytic drink to improve mucosal visualisation in the UK practice.

Narrow band imaging improves observer reliability in evaluation of upper aerodigestive tract lesions

OBJECTIVES/HYPOTHESIS

Visualization by endoscopy is essential in the diagnosis of upper aerodigestive tract lesions. Recent studies showed that narrow band imaging (NBI) increases the diagnostic potential of conventional white light imaging (WLI) by highlighting the superficial vessels. The objective of this study was to evaluate whether the use of NBI would influence inter- and intraobserver agreement while making diagnostic decisions using rigid endoscopy of the upper aerodigestive tract.

STUDY DESIGN

Retrospective study.

METHODS

One hundred routinely collected pictures of laryngeal, hypopharyngeal, and oropharyngeal lesions were used. Rigid endoscopies and patient data collection were performed according to standard protocol. Twelve observers, grouped in different levels of experience, assessed all lesions twice with a 2 to 4 week interval. Fleiss and Cohen's kappa (κ) values were calculated to assess inter- and intraobserver agreement.

RESULTS

Overall interobserver agreement increased from κ = 0.34 to κ = 0.40 by adding NBI to WLI (WLI and WLI + NBI, respectively). In experienced observers, an improvement from κ = 0.39 to κ = 0.43 was observed; in less-experienced observers an improvement from κ = 0.30 to κ = 0.37 was observed. Overall intraobserver agreement increased from moderate (κ = 0.54) to substantial (κ = 0.63) with addition of NBI. Intraobserver agreement for less-experienced observers improved remarkably when WLI was combined with NBI (κ = 0.51 vs. κ = 0.67).

CONCLUSIONS

Addition of NBI during rigid endoscopies of the upper aerodigestive tract led to improvement of both inter- and intraobserver agreement.

LEVEL OF EVIDENCE

4 Laryngoscope, 126:2276-2281, 2016.

Endoscopic imaging of Barrett’s esophagus

The incidence of esophageal adenocarcinoma (EAC) has dramatically increased in the United States as well as Western European countries. The majority of esophageal adenocarcinomas arise from a backdrop of Barrett’s esophagus (BE), a premalignant lesion that can lead to dysplasia and cancer. Because of the increased risk of EAC, GI society guidelines recommend endoscopic surveillance of patients with BE. The emphasis on early detection of dysplasia in BE through surveillance endoscopy has led to the development of advanced endoscopic imaging technologies. These techniques have the potential to both improve mucosal visualization and characterization and to detect small mucosal abnormalities which are difficult to identify with standard endoscopy. This review summarizes the advanced imaging technologies used in evaluation of BE.

Development and Validation of a Classification System to Identify High-Grade Dysplasia and Esophageal Adenocarcinoma in Barrett's Esophagus Using Narrow-Band Imaging

BACKGROUND & AIMS

Although several classification systems have been proposed for characterization of Barrett's esophagus (BE) surface patterns based on narrow-band imaging (NBI), none have been widely accepted. The Barrett's International NBI Group (BING) aimed to develop and validate an NBI classification system for identification of dysplasia and cancer in patients with BE.

METHODS

The BING working group, composed of NBI experts from the United States, Europe, and Japan, met to develop a validated, consensus-driven NBI classification system for identifying dysplasia and cancer in BE. The group reviewed 60 NBI images of nondysplastic BE, high-grade dysplasia, and esophageal adenocarcinoma to characterize mucosal and vascular patterns visible by NBI; these features were used to develop the BING criteria. We then recruited adult patients undergoing surveillance or endoscopic treatment for BE at 4 institutions in the United States and Europe, obtaining high-quality NBI images and performing histologic analysis of biopsies. Experts individually reviewed 50 NBI images to validate the BING criteria, and then evaluated 120 additional NBI images (not previously viewed) to determine whether the criteria accurately predicted the histology results.

RESULTS

The BING criteria identified patients with dysplasia with 85% overall accuracy, 80% sensitivity, 88% specificity, 81% positive predictive value, and 88% negative predictive value. When dysplasia was identified with a high level of confidence, these values were 92%, 91%, 93%, 89%, and 95%, respectively. The overall strength of inter-observer agreement was substantial (κ = 0.681).

CONCLUSIONS

The BING working group developed a simple, internally validated system to identify dysplasia and EAC in patients with BE based on NBI results. When images are assessed with a high degree of confidence, the system can classify BE with >90% accuracy and a high level of inter-observer agreement.

Quality Assurance in Endoscopy: Which Parameters?

BACKGROUND

The verbalisation of quality standards and parameters by medical societies are relevant for qualitative improvement but may also be an instrument to demand more resources for health care or be a unique characteristic. Within the health care system 3 different quality levels can be defined: structure, process and result quality.

METHODS

The current S2k guideline of the German Society for Gastroenterology (quality requirements for gastrointestinal endoscopy) AWMF registry no. 021-022 provides recommendations based on the available evidence for the structure quality (requirements for equipment, human resources) as well as for the process quality (patient preparation, conduct, documentation) and result quality (follow-up of specific endoscopic procedures).

RESULTS

Based on these recommendations, measurable quality indicators/parameters for the endoscopy have been selected and formulated. General quality parameters for endoscopic examinations are given as well as quality parameters for specific procedures for the preparation, conduct, and follow-up of specific endoscopic interventions.

CONCLUSION

Only the regular review of processes and courses by means of defined measurement parameters builds up the basis for corrections based on facts. In addition, the implementation of recommended standards may be an instrument in demanding more resources from the health care system and, therefore, should be embedded as routine.

Diagnosis by Endoscopy and Advanced Imaging of Barrett's Neoplasia

Evaluation of patients with Barrett's esophagus (BE) using dye-based chromoendoscopy, optical chromoendoscopy, autofluorescence imaging, or confocal laser endomicroscopy does not significantly increase the number of patients with a diagnosis of early neoplasia compared with high-definition white light endoscopy (HD-WLE) with random biopsy analysis. These newer imaging techniques are not more effective in standard surveillance of patients with BE because the prevalence of early neoplasia is low and HD-WLE with random biopsy analysis detects most cases of neoplasia. The evaluation and treatment of patients with BE and early stage neoplasia should be centralized in tertiary referral centers, where procedures are performed under optimal conditions, by expert endoscopists. Lesions that require resection are almost always detected by HD-WLE, although advanced imaging techniques can detect additional flat lesions. However, these are of limited clinical significance because they are effectively eradicated by ablation therapy. No endoscopic imaging technique can reliably assess submucosal or lymphangio invasion. Endoscopic resection of early stage neoplasia in patients with BE is important for staging and management. Optical chromoendoscopy can also be used to evaluate lesions before endoscopic resection and in follow-up after successful ablation therapy.

Endoscopic modalities for the diagnosis of Barrett's oesophagus

Barrett's oesophagus is a pre-malignant condition associated with the development of oesophageal adenocarcinoma. Currently white light endoscopy and biopsy is the mainstay diagnostic tool. Yet this approach is troubled by issues related to cumbersome biopsy sampling, biopsy sampling errors and cost. Therefore in order to overcome such adversity, there needs to be evolutionary advancement in terms of diagnosis, which should address these concerns and ideally enhance risk stratification in order to provide timely management in real time. This review highlights the current endoscopic tools aimed to enhance the diagnosis of Barrett's oesophagus and its subsequent progression.

Image enhancement and space-variant color reproduction method for endoscopic images using adaptive sigmoid function

This paper presents an image enhancement and space-variant color reproduction method based on adaptive sigmoid function for endoscopic image. At first, using YCBCR conversion matrix, the color image is separated into luminance and chrominance components. The adaptive sigmoid function with two controlling parameters is applied on the uniformly distributed luminance pixels. The space-variant color reproduction generates new chrominance components by transferring and modifying old chrominance based on texture information. Finally, new luminance and chrominance components are converted into RGB color image. The proposed method highlights some of the tissue and vascular characteristics as well as pit patterns in lesion and polyp. The performance of the proposed scheme is compared with other related methods in terms of image quality, focus value, efficiency of color reproduction and statistic of visual representation.

Advances in the management of Barrett's esophagus and early esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has markedly increased in the United States over the last few decades. Barrett’s esophagus (BE) is the most significant known risk factor for this malignancy. Theoretically, screening and treating early BE should help prevent EAC but the exact incidence of BE and its progression to EAC is not entirely known and cost-effectiveness studies for Barrett’s screening are lacking. Over the last few years, there have been major advances in our understanding of the epidemiology, pathogenesis and endoscopic management of BE. These developments focus on early recognition of advanced histology and endoscopic treatment of high-grade dysplasia. Advanced resection techniques now enable us to endoscopically treat early esophageal cancer. In this review, we will discuss these recent advances in diagnosis and treatment of Barrett’s esophagus and early esophageal adenocarcinoma.

Red flag imaging in Barrett's esophagus: does it help to find the needle in the haystack?

Esophageal Adenocarcinoma (EAC) has suffered a sharp increase on its incidence for the last decades, and it is associated with a poor prognosis. Barrett's Esophagus (BE) is the most important identifiable risk factor for the progression to esophageal adenocarcinoma. The key to prevent and provide a curative treatment of esophageal adenocarcinoma is the detection and eradication of early neoplasia in patients with esophagus. Endoscopic surveillance is evolving from a blind or random four quadrant biopsies protocol (Seattle protocol) to a more targeted approach. A detailed white light examination with high-resolution endoscopy is the cornerstone for recognition of early neoplastic lesions in BE. Additional imaging modalities may enhance targeting of lesions or provide more information at a focused level. There are emerging data that some of these new modalities can increase the yield of detecting dysplasia, although its routine use has yet to be validated.

Detection and characterization of early malignancy in the esophagus: what is the best management algorithm?

Barrett's esophagus is a known precursor for esophageal adenocarcinoma. Early detection of dysplasia provides a window of opportunity for curative intervention. Several image-enhanced technologies have been developed to improve visualization of neoplasia. These however have not been found to be superior to the standard four quadrant random biopsy protocol. Patients are risk-stratified based on the degree of dysplasia found on biopsies and undergo either surveillance or treatment. Endoscopic therapy has become the mainstay of treatment for early neoplasia.

Advanced Imaging in Barrett's Esophagus

Barrett's esophagus (BE) is present in up to 5.6% of the US population and is the precursor lesion for esophageal adenocarcinoma. Surveillance endoscopy is the primary management approach for BE. However, standard protocol biopsies have been associated with significant miss rates of dysplastic lesions in patients with BE. Thus, a variety of methods to optimize the imaging of BE have been developed to improve the efficiency and diagnostic yield of surveillance endoscopy in detecting early neoplasia. These techniques use changes that occur at macroscopic, microscopic, and subcellular levels in early neoplasia and are the focus of this article.

Color Enhancement in Endoscopic Images Using Adaptive Sigmoid Function and Space Variant Color Reproduction

Modern endoscopes play an important role in diagnosing various gastrointestinal (GI) tract related diseases. The improved visual quality of endoscopic images can provide better diagnosis. This paper presents an efficient color image enhancement method for endoscopic images. It is achieved in two stages: image enhancement at gray level followed by space variant chrominance mapping color reproduction. Image enhancement is achieved by performing adaptive sigmoid function and uniform distribution of sigmoid pixels. Secondly, a space variant chrominance mapping color reproduction is used to generate new chrominance components. The proposed method is used on low contrast color white light images (WLI) to enhance and highlight the vascular and mucosa structures of the GI tract. The method is also used to colorize grayscale narrow band images (NBI) and video frames. The focus value and color enhancement factor show that the enhancement level in the processed image is greatly increased compared to the original endoscopic image. The overall contrast level of the processed image is higher than the original image. The color similarity test has proved that the proposed method does not add any additional color which is not present in the original image. The algorithm has low complexity with an execution speed faster than other related methods.

Diagnosis by endoscopy and advanced imaging

Evaluation of patients with Barrett's oesophagus (BO) using dye-based chromoendoscopy, optical chromoendoscopy, autofluorescence imaging, or confocal laser endomicroscopy does not significantly increase the number of patients with a diagnosis of early neoplasia compared with high-definition white light endoscopy (HD-WLE) with random biopsy analysis. These newer imaging techniques are not more effective in standard surveillance of patients with BO because the prevalence of early neoplasia is low and HD-WLE with random biopsy analysis detects most cases of neoplasia. The evaluation and treatment of patients with BO and early-stage neoplasia should be centralized in tertiary referral centers, where procedures are performed under optimal conditions, by expert endoscopists. Lesions that require resection are almost always detected by HD-WLE, although advanced imaging techniques can detect additional flat lesions. However, these are of limited clinical significance because they are effectively eradicated by ablation therapy. No endoscopic imaging technique can reliably assess submucosal or lymphangio-invasion. Endoscopic resection of early-stage neoplasia in patients with BO is important for staging and management. Optical chromoendoscopy can also be used to evaluate lesions before endoscopic resection and in follow-up after successful ablation therapy.

Molecular markers and imaging tools to identify malignant potential in Barrett's esophagus

Due to its rapidly rising incidence and high mortality, esophageal adenocarcinoma is a major public health concern, particularly in Western countries. The steps involved in the progression from its predisposing condition, gastroesophageal reflux disease, to its premalignant disorder, Barrett’s esophagus, and to cancer, are incompletely understood. Current screening and surveillance methods are limited by the lack of population-wide utility, incomplete sampling of standard biopsies, and subjectivity of evaluation. Advances in endoscopic ablation have raised the hope of effective therapy for eradication of high-risk Barrett’s lesions, but improvements are needed in determining when to apply this treatment and how to follow patients clinically. Researchers have evaluated numerous potential molecular biomarkers with the goal of detecting dysplasia, with varying degrees of success. The combination of biomarker panels with epidemiologic risk factors to yield clinical risk scoring systems is promising. New approaches to sample tissue may also be combined with these biomarkers for less invasive screening and surveillance. The development of novel endoscopic imaging tools in recent years has the potential to markedly improve detection of small foci of dysplasia in vivo. Current and future efforts will aim to determine the combination of markers and imaging modalities that will most effectively improve the rate of early detection of high-risk lesions in Barrett’s esophagus.

High definition versus standard definition white light endoscopy for detecting dysplasia in patients with Barrett's esophagus

High-definition endoscopy systems provide superior image resolution. The aim of this study was to assess the utility of high definition compared with standard definition endoscopy system for detecting dysplastic lesions in patients with Barrett's esophagus. A retrospective cohort study of patients with non-dysplastic Barrett's esophagus undergoing routine surveillance was performed. Data were retrieved from the central hospital electronic database. Procedures performed for non-surveillance indications, Barrett's esophagus Prague C0M1 classification with no specialized intestinal metaplasia on histology, patients diagnosed with any dysplasia or cancer on index endoscopy, and procedures using advanced imaging techniques were excluded. Logistic regression models were constructed to estimate adjusted odds ratios and 95% confidence intervals comparing outcomes with standard definition and high-definition systems. The high definition was superior to standard definition system in targeted detection of all dysplastic lesions (odds ratio 3.27, 95% confidence interval 1.27-8.40) as well as overall dysplasia detected on both random and target biopsies (odds ratio 2.36, 95% confidence interval 1.50-3.72). More non-dysplastic lesions were detected with the high-definition system (odds ratio 1.16, 95% confidence interval 1.01-1.33). There was no difference between high definition and standard definition endoscopy in the overall (random and target) high-grade dysplasia or cancers detected (odds ratio 0.93, 95% confidence interval 0.83-1.04). Trainee endoscopists, number of biopsies taken, and male sex were all significantly associated with a higher yield for dysplastic lesions. The use of the high-definition endoscopy system is associated with better targeted detection of any dysplasia during routine Barrett's esophagus surveillance. However, high-definition endoscopy cannot replace random biopsies at present time.

Endoscopic assessment and management of early esophageal adenocarcinoma

Esophageal carcinoma affects more than 450000 people worldwide and the incidence is rapidly increasing. In the United States and Europe, esophageal adenocarcinoma has superseded esophageal squamous cell carcinoma in its incidence. Esophageal cancer has a high mortality rates secondary to the late presentation of most patients at advanced stages. Endoscopic screening is recommended for patients with multiple risk factors for cancer in Barrett’s esophagus. These risk factors include chronic gastroesophageal reflux disease, hiatal hernia, advanced age, male sex, white race, cigarette smoking, and obesity. The annual risk of esophageal cancer is approximately 0.25% for patients without dysplasia and 6% for patients with high-grade dysplasia. Twenty percent of all esophageal adenocarcinoma in the United States is early stage with disease confined to the mucosa or submucosa. The significant morbidity and mortality of esophagectomy make endoscopic treatment an attractive option. The American Gastroenterological Association recommends endoscopic eradication therapy for patients with high-grade dysplasia. Endoscopic modalities for treatment of early esophageal adenocarcinoma include endoscopic resection techniques and endoscopic ablative techniques such as radiofrequency ablation, photodynamic therapy and cryoablation. Endoscopic therapy should be precluded to patients with no evidence of lymphovascular invasion. Local tumor recurrence is low after endoscopic therapy and is predicted by poor differentiation of tumor, positive lymph node and submucosal invasion. Surgical resection should be offered to patients with deep submucosal invasion.

Digital chrome endoscopy for diagnosis of Barrett's esophagus

AIM: To evaluate the diagnostic value of digital chrome endoscopy (I-Scan) in Barrett's esophagus (BE).

METHODS: From August 2012 to March 2013, a total of 420 patients with reflux esophageal disease were enrolled. The patients were randomized into two groups: one group (n = 220) received I-Scan and the other received ordinary endoscopy. Those suspected to have BE were observed closely and underwent biopsy. The detection rate and diagnostic accuracy were compared between the two endoscopic modes.

RESULTS: Suspected BE was diagnosed in 35 patients (15.91%) by I-Scan and in 24 (12.00%) by ordinary endoscopy. There was no significant difference in the detection rate for BE between the two methods (P > 0.05). The coincidence rate of diagnosis between I-Scan and pathology was 87.10%, and was 70.83% for the ordinary endoscopy, with a significant difference between the two groups (P < 0.05). The image score of paliform blood vessels was significant difference between squamoucolumnar junction (SCJ) and gastroesophageal junction (GEJ) (P < 0.05).

CONCLUSION: I-Scan could play an important role in the observation of paliform blood vessels between SCJ and GEJ in BE. The dignostic rate of I-Scan might be better than that of ordinary endoscopy. I-Scan can improve the detection rate for BE.

State of the art in advanced endoscopic imaging for the detection and evaluation of dysplasia and early cancer of the gastrointestinal tract

Ideally, endoscopists should be able to detect, characterize, and confirm the nature of a lesion at the bedside, minimizing uncertainties and targeting biopsies and resections only where necessary. However, under conventional white-light inspection – at present, the sole established technique available to most of humanity – premalignant conditions and early cancers can frequently escape detection. In recent years, a range of innovative techniques have entered the endoscopic arena due to their ability to enhance the contrast of diseased tissue regions beyond what is inherently possible with standard white-light endoscopy equipment. The aim of this review is to provide an overview of the state-of-the-art advanced endoscopic imaging techniques available for clinical use that are impacting the way precancerous and neoplastic lesions of the gastrointestinal tract are currently detected and characterized at endoscopy. The basic instrumentation and the physics behind each method, followed by the most influential clinical experience, are described. High-definition endoscopy, with or without optical magnification, has contributed to higher detection rates compared with white-light endoscopy alone and has now replaced ordinary equipment in daily practice. Contrast-enhancement techniques, whether dye-based or computed, have been combined with white-light endoscopy to further improve its accuracy, but histology is still required to clarify the diagnosis. Optical microscopy techniques such as confocal laser endomicroscopy and endocytoscopy enable in vivo histology during endoscopy; however, although of invaluable assistance for tissue characterization, they have not yet made transition between research and clinical use. It is still unknown which approach or combination of techniques offers the best potential. The optimal method will entail the ability to survey wide areas of tissue in concert with the ability to obtain the degree of detailed information provided by microscopic techniques. In this respect, the challenging combination of autofluorescence imaging and confocal endomicroscopy seems promising, and further research is awaited.

Meta-analysis of the effects of endoscopy with narrow band imaging in detecting dysplasia in Barrett's esophagus

Narrow band imaging (NBI) is a real-time imaging technique. The aim of this meta-analysis was to estimate the sensitivity, specificity, and diagnostic accuracy on the role of NBI in the detection and characterization of specialized intestinal metaplasia (SIM), high-grade dysplasia (HGD) in the Barrett's esophagus. We identified studies by performing a literature search of Medline, EMBASE, and the Cochrane Library databases up to May 2013. We performed data analysis using Meta-DiSc (version 1.4) software. To assess study quality and potential for bias, we used the Quality Assessment of Diagnostic Accuracy Studies-2 tool (QUADAS-2). Overall, seven eligible studies including over 3988 lesions of 502 patients were retrieved. The results showed that endoscopic diagnosis of dysplasia performed using NBI has a high diagnostic performance, with an area under the summary receiver operating characteristic (SROC) curve near 0.90 both in HGD lesions and SIM lesions. We also found that NBI has a sensitive and specificity of 0.91 (95% confidence interval [CI] = 0.86-0.94) and 0.85 (95% CI = 0.76-0.92) on a per-patient element, and 0.97 (95% CI = 0.95-0.98) and 0.64 (95% CI = 0.59-0.68) on a per-lesion element for SIM diagnosis, respectively. The pooled per-patient sensitivity and specificity for identifying HGD are 0.91 (95% CI = 0.75-0.98) and 0.95 (95% CI = 0.91-0.97). The pooled per-lesion sensitivity and specificity for identifying HGD are 0.69 (95% CI = 0.63-0.74) and 0.90 (95% CI = 0.88-0.91). In conclusion, we found that endoscopic diagnosis with NBI is an accurate test to diagnosis dysplasia of Barrett's esophagus.

Near-infrared fluorescence cholangiopancreatoscopy: initial clinical feasibility results

BACKGROUND

The recent clinical propagation of targeted fluorescence agents brings a promising alternative in endoscopy by complementing visual disease detection with molecular biomarkers.

OBJECTIVE

Development of near-infrared (NIR) fluorescence cholangiopancreatoscopy in real-time and validation of its clinical use.

DESIGN

Feasibility study.

SETTING

Tertiary referral center at a large university hospital.

PATIENTS

Patients with pancreatic and biliary diseases.

INTERVENTIONS

Routine cholangiopancreatoscopy with additional wide-field NIR fluorescence imaging.

MAIN OUTCOME MEASUREMENTS

We adapted a miniature cholangioscope for real-time concurrent wide-field color and NIR fluorescence imaging. Illumination is provided through a custom-designed fiber bundle, and the acquired images are relayed via a dichroic beam splitter to 2 charge-coupled devices for simultaneous measurement. We characterize the sensitivity and resolution and demonstrate the clinical feasibility by detecting indocyanine green localization in 2 patients.

RESULTS

A spatial optical resolution of approximately 50 μm was achieved, and fluorescent dye concentrations of 17.3 nM could be detected. Elevated fluorescence signals were detected during clinical measurements, and biopsy specimens confirmed the presence of malignancy in both patients.

LIMITATIONS

Feasibility study, limited number of patients.

CONCLUSIONS

The results demonstrate that real-time wide-field fluorescence detection in the NIR range is possible in humans by using adapted endoscopes. The feasibility of detecting indocyanine green in the pancreatobiliary ducts is verified, suggesting that cancer screening at a molecular level might play an increasingly important role in the future.

The clinical consequences of advanced imaging techniques in Barrett's esophagus

Evaluation of patients with Barrett's esophagus (BE) using dye-based chromoendoscopy, optical chromoendoscopy, autofluorescence imaging, or confocal laser endomicroscopy does not significantly increase the number of patients with a diagnosis of early neoplasia compared with high-definition white light endoscopy (HD-WLE) with random biopsy analysis. These newer imaging techniques are not more effective in standard surveillance of patients with BE because the prevalence of early neoplasia is low and HD-WLE with random biopsy analysis detects most cases of neoplasia. The evaluation and treatment of patients with BE and early-stage neoplasia should be centralized in tertiary referral centers, where procedures are performed under optimal conditions, by expert endoscopists. Lesions that require resection are almost always detected by HD-WLE, although advanced imaging techniques can detect additional flat lesions. However, these are of limited clinical significance because they are effectively eradicated by ablation therapy. No endoscopic imaging technique can reliably assess submucosal or lymphangio-invasion. Endoscopic resection of early-stage neoplasia in patients with BE is important for staging and management. Optical chromoendoscopy can also be used to evaluate lesions before endoscopic resection and in follow-up after successful ablation therapy.

Advanced endoscopic imaging: a review of commercially available technologies

The rapid strides made in innovative endoscopic technology to improve mucosal visualization have revolutionized endoscopy. Improved lesion detection has allowed the modern endoscopist to provide real-time optical diagnosis. Improvements in image resolution, software processing, and optical filter technology have resulted in the commercial availability of high-definition endoscopy as well as optical contrast techniques such as narrow-band imaging, flexible spectral imaging color enhancement, and i-scan. Along with autofluorescence imaging and confocal laser endomicroscopy, these techniques have complemented and enhanced traditional white light endoscopy. They have the potential to serve as red-flag techniques to improve detection of mucosal abnormalities as well as allow optical diagnosis and virtual histology of detected lesions. This review will focus on these emerging commercially available technologies and aims to provide an overview of the technologies, their clinical applicability, and current status.