Endoscopic assessment and grading of Barrett's esophagus using magnification endoscopy and narrow band imaging: impact of structured learning and experience on the accuracy of the Amsterdam classification system

A simpler diagnostic algorithm of the Japan Esophageal Society classification for Barrett's esophagus-related superficial neoplasia

BACKGROUND

We previously developed a Japan Esophageal Society Barrett's Esophagus (JES-BE) magnifying endoscopic classification for superficial BE-related neoplasms (BERN) and validated it in a nationwide multicenter study that followed a diagnostic flow chart based on mucosal and vascular patterns (MP, VP) with nine diagnostic criteria. Our present post hoc analysis aims to further simplify the diagnostic criteria for superficial BERN.

METHODS

We used data from our previous study, including 10 reviewers' assessments for 156 images of high-magnifying narrow-band imaging (HM-NBI) (67 dysplastic and 89 non-dysplastic histology). We statistically analyzed the diagnostic performance of each diagnostic criterion of MP (form, size, arrangement, density, and white zone), VP (form, caliber change, location, and greenish thick vessels [GTV]), and all their combinations to achieve a simpler diagnostic algorithm to detect superficial BERN.

RESULTS

Diagnostic accuracy values based on the MP of each single criterion or combined criteria showed a marked trend of being higher than those based on VP. In reviewers' assessments of visible MPs, the combination of irregularity for form, size, or white zone had the highest diagnostic performance, with a sensitivity of 87% and a specificity of 91% for dysplastic histology; in the assessments of invisible MPs, GTV had the highest diagnostic performance among the VP of each single criterion and all combinations of two or more criteria (sensitivity, 93%; specificity, 92%).

CONCLUSION

The present post hoc analysis suggests the feasibility of further simplifying the diagnostic algorithm of the JES-BE classification. Further studies in a practical setting are required to validate these results.

Deep Learning in Barrett's Esophagus Diagnosis: Current Status and Future Directions

Barrett's esophagus (BE) represents a pre-malignant condition characterized by abnormal cellular proliferation in the distal esophagus. A timely and accurate diagnosis of BE is imperative to prevent its progression to esophageal adenocarcinoma, a malignancy associated with a significantly reduced survival rate. In this digital age, deep learning (DL) has emerged as a powerful tool for medical image analysis and diagnostic applications, showcasing vast potential across various medical disciplines. In this comprehensive review, we meticulously assess 33 primary studies employing varied DL techniques, predominantly featuring convolutional neural networks (CNNs), for the diagnosis and understanding of BE. Our primary focus revolves around evaluating the current applications of DL in BE diagnosis, encompassing tasks such as image segmentation and classification, as well as their potential impact and implications in real-world clinical settings. While the applications of DL in BE diagnosis exhibit promising results, they are not without challenges, such as dataset issues and the "black box" nature of models. We discuss these challenges in the concluding section. Essentially, while DL holds tremendous potential to revolutionize BE diagnosis, addressing these challenges is paramount to harnessing its full capacity and ensuring its widespread application in clinical practice.

Computer-aided characterization of early cancer in Barrett's esophagus on i-scan magnification imaging: a multicenter international study

BACKGROUND AND AIMS

We aimed to develop a computer-aided characterization system that could support the diagnosis of dysplasia in Barrett's esophagus (BE) on magnification endoscopy.

METHODS

Videos were collected in high-definition magnification white-light and virtual chromoendoscopy with i-scan (Pentax Hoya, Japan) imaging in patients with dysplastic and nondysplastic BE (NDBE) from 4 centers. We trained a neural network with a Resnet101 architecture to classify frames as dysplastic or nondysplastic. The network was tested on 3 different scenarios: high-quality still images, all available video frames, and a selected sequence within each video.

RESULTS

Fifty-seven patients, each with videos of magnification areas of BE (34 dysplasia, 23 NDBE), were included. Performance was evaluated by a leave-1-patient-out cross-validation method. In all, 60,174 (39,347 dysplasia, 20,827 NDBE) magnification video frames were used to train the network. The testing set included 49,726 i-scan-3/optical enhancement magnification frames. On 350 high-quality still images, the network achieved a sensitivity of 94%, specificity of 86%, and area under the receiver operator curve (AUROC) of 96%. On all 49,726 available video frames, the network achieved a sensitivity of 92%, specificity of 82%, and AUROC of 95%. On a selected sequence of frames per case (total of 11,471 frames), we used an exponentially weighted moving average of classifications on consecutive frames to characterize dysplasia. The network achieved a sensitivity of 92%, specificity of 84%, and AUROC of 96%. The mean assessment speed per frame was 0.0135 seconds (SD ± 0.006).

CONCLUSION

Our network can characterize BE dysplasia with high accuracy and speed on high-quality magnification images and sequence of video frames, moving it toward real-time automated diagnosis.

Effect of adding acetic acid when performing magnifying endoscopy with narrow band imaging for diagnosis of Barrett's esophageal adenocarcinoma

Background and study aims  Magnifying endoscopy with narrow band imaging (M-NBI) was developed to diagnose Barrett's esophageal adenocarcinoma (BEA); however, this method remains challenging for inexperienced endoscopists. We aimed to evaluate a modified M-NBI technique that included spraying acetic acid (M-AANBI). Patients and methods  Eight endoscopists retrospectively examined 456 endoscopic images obtained from 28 patients with 29 endoscopically resected BEA lesions using three validation schemes: Validation 1 (260 images), wherein the diagnostic performances of M-NBI and M-AANBI were compared - the dataset included 65 images each of BEA and non-neoplastic Barrett's esophagus (NNBE) obtained using each modality; validation 2 (112 images), wherein 56 pairs of M-NBI and M-AANBI images were prepared from the same BEA and NNBE lesions, and diagnoses derived using M-NBI alone were compared to those obtained using both M-NBI and M-AANBI; and validation 3 (84 images), wherein the ease of identifying the BEA demarcation line (DL) was scored via a visual analog scale in 28 patients using magnifying endoscopy with white-light imaging (M-WLI), M-NBI, and M-AANBI. Results  For validation 1, M-AANBI was superior to M-NBI in terms of sensitivity (90.8 % vs. 64.6 %), specificity (98.5 % vs. 76.9 %), and accuracy (94.6 % vs. 70.4 %) (all P  < 0.05). For validation 2, the accuracy of M-NBI alone was significantly improved when combined with M-AANBI (from 70.5 % to 89.3 %; P  < 0.05). For validation 3, M-AANBI had the highest mean score for ease of DL recognition (8.75) compared to M-WLI (3.63) and M-NBI (6.25) (all P <  0.001). Conclusions  Using M-AANBI might improve the accuracy of BEA diagnosis.

Taking the Next Steps in Endoscopic Visual Assessment of Barrett's Esophagus: A Pilot Study

Purpose

Patients with Barrett's esophagus (BE) undergo surveillance endoscopies to assess for pre-cancerous changes. We developed a simple endoscopic classification method for predicting non-dysplastic BE (NDBE), low-grade dysplasia (LGD)/indefinite for dysplasia (ID) and high-grade dysplasia (HGD)/early esophageal adenocarcinoma (EAC).

Patients and Methods

Twenty-two patients with BE underwent endoscopy using the PENTAX Medical MagniView gastroscope and OPTIVISTA processor. Sixty-six video-still images were analyzed to characterize the microsurface, microvasculature and the presence of a demarcation line. Class A was characterized by regular microvascular and microsurface patterns and absence of a demarcation line, class B by changes in the microvascular and/or microsurface patterns compared to the background mucosa with presence of a demarcation line, and class C by irregular microvascular and/or irregular microsurface patterns with presence of a demarcation line.

Results

Of the class A images, 97.9% were NDBE. For class B, 69.2% were LGD/ID and 30.8% NDBE. One hundred percent of the class C samples were HGD/EAC. The sensitivity of our classification system was 93.8%, specificity 92%, positive predictive value 78.9%, negative predictive value 97.9% and an accuracy 92.4%.

Conclusion

In this study, we developed a simple classification system for the prediction of NDBE, LGD/ID and HGD/EAC. Its real-time clinical applicability will be validated prospectively.

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.

Curriculum for optical diagnosis training in Europe: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement

This manuscript represents an official Position Statement of the European Society of Gastrointestinal Endoscopy (ESGE) aiming to guide general gastroenterologists to develop and maintain skills in optical diagnosis during endoscopy. In general, this requires additional training beyond the core curriculum currently provided in each country. In this context, ESGE have developed a European core curriculum for optical diagnosis practice across Europe for high quality optical diagnosis training. 1:  ESGE suggests that every endoscopist should have achieved general competence in upper and/or lower gastrointestinal (UGI/LGI) endoscopy before commencing training in optical diagnosis of the UGI/LGI tract, meaning personal experience of at least 300 UGI and/or 300 LGI endoscopies and meeting the ESGE quality measures for UGI/LGI endoscopy. ESGE suggests that every endoscopist should be able and competent to perform UGI/LGI endoscopy with high definition white light combined with virtual and/or dye-based chromoendoscopy before commencing training in optical diagnosis. 2:  ESGE suggests competency in optical diagnosis can be learned by attending a validated optical diagnosis training course based on a validated classification, and self-learning with a minimum number of lesions. If no validated training course is available, optical diagnosis can only be learned by attending a non-validated onsite training course and self-learning with a minimum number of lesions. 3:  ESGE suggests endoscopists are competent in optical diagnosis after meeting the pre-adoption and learning criteria, and meeting competence thresholds by assessing a minimum number of lesions prospectively during real-time endoscopy. ESGE suggests ongoing in vivo practice by endoscopists to maintain competence in optical diagnosis. If a competent endoscopist does not perform in vivo optical diagnosis on a regular basis, ESGE suggests repeating the learning and competence phases to maintain competence.Key areas of interest were optical diagnosis training in Barrett's esophagus, esophageal squamous cell carcinoma, early gastric cancer, diminutive colorectal lesions, early colorectal cancer, and neoplasia in inflammatory bowel disease. Condition-specific recommendations are provided in the main document.

Barrett’s Esophagus in Romania: what do we know?

Background and aims. The incidence of Barrett’s Esophagus (BE) is increasing worldwide, thus diagnosis is becoming a major key of interest in preventing esophageal adenocarcinoma. Because the status of BE in Romania is unclear, we performed a narrative review to comprehensively evaluate all published articles on BE from Romania.

Methods. We conducted a systematic literature search of PubMed data base and of all Romanian medical journals. The abstracts and the titles of the identified studies were reviewed to exclude the studies that did not answer the search question. In addition we performed a manual search to identify articles on this topic published earlier in local journals or not indexed on internet.

Results. A total of 17 articles were found. 8 studies and 9 reviews were identified, with a total of 8,829 participants enrolled. The results showed that the median age ranges between 54–59 years, with a predominance for male sex, the main risk factors, such as gastroesophageal reflux disease, obesity, smoking, hiatal hernia, are also present in Romania and infection with H. pylori has a protective effect. The diagnosis of Barrett’s esophagus in Romania is established in agreement with international guidelines.

Conclusions. There are not many publications on BE in Romania. However the data in this country are similar to those reported in other countries. The management is carried out according to standard guidelines. Diagnosing BE relies on endoscopic techniques and classification systems. Risk factors such as gastroesophageal reflux, hiatal hernia, obesity and Helicobacter pylori are considered in Romanian articles. More studies are welcome on this matter in our country.

Development and validation of the international Blue Light Imaging for Barrett's Neoplasia Classification

BACKGROUND AND AIMS

Detecting subtle Barrett's neoplasia during surveillance endoscopy can be challenging. Blue-light imaging (BLI) is a novel advanced endoscopic technology with high-intensity contrast imaging that may improve the identification of Barrett's neoplasia. The aim of this study was to develop and validate the first classification to enable characterization of neoplastic and non-neoplastic Barrett's esophagus using BLI.

METHODS

In phase 1, descriptors pertaining to neoplastic and non-neoplastic Barrett's esophagus were identified to form the classification, named the Blue Light Imaging for Barrett's Neoplasia Classification (BLINC). Phase 2 involved validation of these component criteria by 10 expert endoscopists assessing 50 BLI images. In phase 3, a web-based training module was developed to enable 15 general (nonexpert) endoscopists to use BLINC. They then validated the classification with an image assessment exercise in phase 4, and their pre- and post-training results were compared.

RESULTS

In phase 1 the descriptors were grouped into color, pit, and vessel pattern categories to form the classification. In phase 2 the sensitivity of neoplasia identification was 96.0% with a very good level of agreement among the experts (κ = .83). In phase 3, 15 general endoscopists completed the training module. In phase 4 their pretraining sensitivity (85.3%) improved significantly to 95.7% post-training with a good level of agreement (κ = .67).

CONCLUSIONS

We developed and validated a new classification system (BLINC) for the optical diagnosis of Barrett's neoplasia using BLI. Despite the limitations of this image-based study with a high prevalence of neoplasia, we believe it has the potential to improve the optical diagnosis of Barrett's neoplasia given the high degree of sensitivity (96%) noted. It is also a promising tool for training in Barrett's esophagus optical diagnosis using BLI.

Learning curve for endoscopic evaluation of vocal folds lesions with narrow band imaging

Introduction

The endoscopic methods are progressing and becoming more common in routine clinical diagnosis in the field of otorhinolaryngology. Relatively large amount of researches have proved high accuracy of narrow band imaging endoscopy in differentiating benign and malignant lesions within vocal folds. However, little is known about learning curve in narrow band imaging evaluation of laryngeal lesions.

Objective

The aim of this study was to determine the learning curve for the narrow band imaging evaluation of vocal folds pathologies depending on the duration of the procedure.

Methods

Records of 134 narrow band imaging that were analyzed in terms of the duration of the procedure and the accuracy of diagnosis confirmed by histopathological diagnosis were enrolled in the study. The narrow band imaging examinations were performed sequentially by one investigator over a period of 18 months.

Results

The average duration of narrow band imaging recordings was 127.82 s. All 134 studies were divided into subsequent series of several elements. An evident decrease in time of investigation was noticed between 13th and 14th series, when the examinations were divided into 5 elements series, which corresponds to the difference between 65th and 70th subsequent narrow band imaging examination. Parallel groups of 67 examinations were created. Group 1 included 1st to 67th subsequent narrow band imaging examination; Group 2 – 68th to 134th narrow band imaging examinations. The non-parametric U Mann–Whitney test confirmed statistically significant difference between the mean duration of narrow band imaging examination in both groups 160.5 s and 95.1 s, respectively (p < 10⁻⁷). Sensitivity and specificity of narrow band imaging examination in the first group were respectively: 83.7% and 76.7%. In the second group, these indicators amounted 98.1% and 80% respectively.

Conclusions

A minimum of 65th–70th narrow band imaging examinations are required to reach a plateau phase of the learning process in assessment of glottis lesions. Analysis of learning curves is useful for the development of training programs and determination of a mastery level.

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.

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.

Endoscopic classification of the papilla of Vater. Results of an inter- and intraobserver agreement study

BACKGROUND

Many endoscopists acknowledge that the appearance of the papilla of Vater seems to affect biliary cannulation. To assess the association between the macroscopic appearance of the papilla and biliary cannulation and other related clinical issues, a system is needed to define the appearance of the papilla.

OBJECTIVE

The purpose of this study was to validate an endoscopic classification of the papilla of Vater by assessing the interobserver and intraobserver agreements among endoscopist with varying experience.

METHODS

An endoscopic classification, based on pictures captured from 140 different papillae, containing four types of papillae was proposed. The four types are (a) Type 1: regular papilla, no distinctive features, 'classic appearance'; (b) Type 2: small papilla, often flat, with a diameter ≤ 3 mm (approximately 9 Fr); (c) Type 3: protruding or pendulous papilla, a papilla that is standing out, protruding or bulging into the duodenal lumen or sometimes hanging down, pendulous with the orifice oriented caudally; and (d) Type 4: creased or ridged papilla, where the ductal mucosa seems to extend distally, rather out of the papillary orifice, either on a ridge or in a crease. To assess the level of interobserver agreement, a web-based survey was sent out to 18 endoscopists, containing 50 sets of still images of the papilla, distributed between the four different types. Three months later a follow-up survey, with images from the first survey was sent to the same endoscopists.

RESULTS

Interobserver agreement was substantial (κ = 0.62, 95% confidence interval (CI) 0.58-0.65) and were similar for both experts and non-experts. The intraobserver agreement assessed with the second survey was also substantial (κ = 0.66, 95% CI 0.59-0.72).

CONCLUSION

The proposed endoscopic classification of the papilla of Vater seems to be easy to use, irrespective of the level of experience of the endoscopist. It carries a substantial inter- and intraobserver agreement and now the clinical relevance of the four different papilla types awaits to be determined.

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.

Randomized controlled trial of self-directed versus in-classroom teaching of narrow-band imaging for diagnosis of Barrett's esophagus-associated neoplasia

BACKGROUND AND AIMS

Previous studies have shown that narrow-band imaging (NBI) can be taught to inexperienced gastroenterologists. However, it is unknown whether in-person training is more effective than self-directed training. The objective of this study was to compare the accuracy of diagnosing Barrett's esophagus (BE)-associated neoplasia by trainees with no prior NBI experience between in-classroom and self-directed didactic training programs.

METHODS

This was a randomized controlled trial that took place at 2 tertiary-care medical centers, involving 33 participants--12 second-year medical students, 8 first-year gastroenterology fellows, 7 second-year gastroenterology fellows, and 6 third-year gastroenterology fellows. A teaching module was developed for all participants to review. Half of the participants were taught in a classroom setting by an endoscopist with expertise in NBI, whereas the other participants were in a self-directed group that received an automated version of the presentation with audio commentary. Participants completed a test of 40 randomized NBI images, predicting the histology and indicating their confidence levels in the diagnosis.

RESULTS

There was no difference in accuracy between the in-classroom and self-directed groups (57.5% vs 57.2%; P = 1.0). The in-classroom group had a significantly higher percentage of high-confidence answers (57.2% vs 41.1%; P ≤ .01), but there was no significant difference in accuracy with these high-confidence answers (60.7% vs 66.4%; P = .34). There was no significant difference in overall accuracy or accuracy with high-confidence predictions between the 2 study sites (57.4% vs 55.9%, P = .58; 63.1% vs 61.4%, P = .69) or between gastroenterology fellows and medical students (57.8% vs 54.6%, P = .27; 62.8% vs 60.8%, P = .62).

CONCLUSIONS

The overall accuracy of predicting NBI patterns in BE were modest in our study participants, and there was no difference between self-directed and in-classroom didactic training. Self-directed learning of NBI is adequate for teaching NBI to trainees.

Pathophysiology of Barrett's esophagus-associated neoplasia: circumferential spatial predilection

The prevalence rates of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) arising from BE show striking geographic patterns as they are much more common in Western as compared with Asian countries. However, recent epidemiological studies indicate that the number of patients with BE and EAC are gradually increasing in Asia including Japan, corresponding to the increase in prevalence of gastroesophageal reflux disease (GERD). Because the prognosis of patients with advanced-stage EAC remains poor, early detection of neoplastic lesion in those with BE has led to recent interest in effective treatment. Several promising studies have revealed that early neoplasia in BE is mainly located in the right anterior wall of the distal esophagus. Interestingly, this endoscopic characteristic has been found in both Western and Japanese populations. Potential pathophysiologic explanations underlying the circumferential distribution of neoplasia in BE include a nonuniform asymmetric distribution of esophageal acid exposure, with a tendency toward mucosal acid-related injury on the right side of the esophageal wall in patients with GERD, and the functional structure of the lower esophageal sphincter. Findings of the present study should improve lesion detection and aid in developing a target biopsy protocol for surveillance of BE.

Electronic chromoendoscopy

Electronic chromoendoscopy technologies provide image enhancement and may improve the diagnosis of mucosal lesions. Although strides have been made in standardization of image characterization, especially with NBI, further image-to-pathology correlation and validation are required. There is promise for the development of a resect and discard policy for diminutive adenomas by using electronic chromoendoscopy; however, before this can be adopted, further community-based studies are needed. Further validated training tools for NBI, FICE, and i-SCAN will also be required for the use of these techniques to become widespread.

Narrow-band imaging and white-light endoscopy with optical magnification in the diagnosis of dysplasia in Barrett's esophagus: results of the Asia-Pacific Barrett's Consortium

OBJECTIVE

The advent and utility of new endoscopic imaging modalities for predicting the histology of Barrett's esophagus (BE) in real time with high accuracy appear promising and could potentially obviate the need to perform random biopsies where guidelines are poorly adhered to. We embarked on evaluating the performance characteristics of white-light endoscopy with magnification (WLE-z), narrow-band imaging with magnification (NBI-z) and a combination of both modalities.

DESIGN

This was a prospective online study with 28 endoscopists from 11 countries (Asia-Pacific region) participating as assessors. In total, 35 patients with BE were assessed using 150 slides from WLE-z and NBI-z randomly arranged using a simple classification with corresponding histology. The overall Accuracy (Acc), Sensitivity (Sn), Specificity (Sp), Positive Predictive Value (PPV), and Negative Predictive Value (NPV) of WLE-z, NBI-z and a combination of both were calculated.

RESULTS

The overall Acc for WLE-z and NBI-z images was 87.1 % and 88.7 %, respectively. When images from the two modalities were placed side by side, the Acc increased to 90.3 %. The Sn, Sp, PPV, and NPV of WLE-z were 48 %, 92 %, 45 %, and 93 % while with NBI-z, these improved to 89 %, 89 %, 56 %, and 98 %, respectively. When both imaging modalities were viewed together, they improved further to 93 %, 90 %, 61 %, and 99 %.

CONCLUSION

The high NPV (99 %) when both WLE-z and NBI-z were used simultaneously indicates that areas with regular appearance that are diagnosed with confidence can effectively be left alone and not biopsied when performed at a skilled resourced center. This approach could potentially lead to a paradigm shift of how patients with BE are assessed.

Simplified classification of capillary pattern in Barrett esophagus using magnifying endoscopy with narrow band imaging: implications for malignant potential and interobserver agreement

The classification of Barrett esophagus (BE) using magnifying endoscopy with narrow band imaging (ME-NBI) is not widely used in clinical settings because of its complexity. To establish a new simplified available classification using ME-NBI.We conducted a cross-sectional study in a single-referral center. One hundred eight consecutive patients with BE using ME-NBI and crystal violet (CV) chromoendoscopy, and histological findings were enrolled. BE areas observed by ME-NBI were classified as type I or II on the basis of capillary pattern (CP), and as closed or open type on the basis of a mucosal pit pattern using CV chromoendoscopy; then, biopsy samples were obtained. We evaluated the relation between CP and pit pattern, expression of the factors with malignant potential, percentage of microvascular density, and interobserver agreement.One hundred thirty lesions from 91 patients were analyzed. Type II CP had more open type pit pattern areas and significantly greater microvascular density than type I. The presence of dysplasia, specialized intestinal metaplasia, expressions of COX-2, CDX2, and CD34, and PCNA index were significantly higher in type II, whereas the multivariate analysis showed that type II was the best predictor for the presence of dysplasia (OR 11.14), CD34 expression (OR 3.60), and PCNA (OR 3.29). Interobserver agreement for this classification was substantial (κ = 0.66).A simplified CP classification based on observation with ME-NBI is presented. Our results indicate that the classification may be useful for surveillance of BE with high malignant potential.

Assessment of the diagnostic performance and interobserver variability of endocytoscopy in Barrett’s esophagus: A pilot ex-vivo study

AIM: To investigate a classification of endocytoscopy (ECS) images in Barrett’s esophagus (BE) and evaluate its diagnostic performance and interobserver variability.

METHODS: ECS was applied to surveillance endoscopic mucosal resection (EMR) specimens of BE ex-vivo. The mucosal surface of specimen was stained with 1% methylene blue and surveyed with a catheter-type endocytoscope. We selected still images that were most representative of the endoscopically suspect lesion and matched with the final histopathological diagnosis to accomplish accurate correlation. The diagnostic performance and inter-observer variability of the new classification scheme were assessed in a blinded fashion by physicians with expertise in both BE and ECS and inexperienced physicians with no prior exposure to ECS.

RESULTS: Three staff physicians and 22 gastroenterology fellows classified eight randomly assigned unknown still ECS pictures (two images per each classification) into one of four histopathologic categories as follows: (1) BEC1-squamous epithelium; (2) BEC2-BE without dysplasia; (3) BEC3-BE with dysplasia; and (4) BEC4-esophageal adenocarcinoma (EAC) in BE. Accuracy of diagnosis in staff physicians and clinical fellows were, respectively, 100% and 99.4% for BEC1, 95.8% and 83.0% for BEC2, 91.7% and 83.0% for BEC3, and 95.8% and 98.3% for BEC4. Interobserver agreement of the faculty physicians and fellows in classifying each category were 0.932 and 0.897, respectively.

CONCLUSION: This is the first study to investigate classification system of ECS in BE. This ex-vivo pilot study demonstrated acceptable diagnostic accuracy and excellent interobserver agreement.