Is there a role for new imaging techniques in endoscopic surveillance?

L’incidence de la dégénérescence néoplasique dans l’oesophage de Barrett est en nette augmentation dans les pays occidentaux. La surveillance endoscopique visant à détecter cette pathologie à un stade précoce joue un rôle majeur dans la survie globale après chirurgie. Grâce aux techniques nouvelles telles que la résection endoscopique ou l’ablation par radiofréquence, maintenant disponibles pour traiter la maladie de manière moins invasive, la détection précoce de la dysplasie devient un enjeu de tout premier ordre. Récemment, plusieurs procédés nouveaux ont été mis en oeuvre, visant à une meilleure efficacité au niveau de la détection de la dysplasie. Ce sont la chromoendoscopie classique, la chromo endoscopie virtuelle, l’imagerie par auto-fluorescence et l’endomicroscopie confocale. Parmi elles, l’imagerie par autofluorescence semble la plus prometteuse en tant qu’outil d’alerte alors que la chromoendoscopie virtuelle aide à caractériser les lésions. L’endomicroscopie confocale permet une étude histologique in vivo et aide à confirmer le diagnostic de lésions néoplasiques. En règle générale, le rôle exact de ces nouveaux procédés d’imagerie dans un programme général de détection n’a pas été réellement envisagé, si bien qu’actuellement, le gold standard pour la surveillance de l’oesophage de Barrett reste toujours l’endoscopie haute définition en lumière blanche et le protocole de Seattle.The incidence of Barrett’s associated neoplasia is rising in the Western world. Endoscopic surveillance in order to detect this disease in an earlier stage has implication on overall survival after surgery. With new techniques such as endoscopic resection or radiofrequency ablation available now to treat the disease in a less invasive way, early detection of dysplasia becomes even more important. Recently several new imaging modalities have become available with a possible improvement in efficiency for detecting dysplasia. These include classical chromo-endoscopy, virtual chromo-endoscopy, autofluorescence imaging and confocal endomicroscopy. Of these autofluorescence imaging seems most promising as a red flag technique, whereas (virtual) chromoendoscopy helps to characterize lesions. Confocal endomicroscopy enables in vivo histology and helps to confirm neoplastic lesions. In general, the exact role of these new imaging modalities in a general screening program has not been addressed, so currently a thorough inspection with white light high definition endoscopy and the Seattle protocol are still the gold standard to survey Barrett’s patients

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

BACKGROUND AND AIMS: We aimed to develop a computer aided characterization system that can 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/ non-dysplastic BE (NDBE) from 4 centres. We trained a neural network with a Resnet101 architecture to classify frames as dysplastic or non-dysplastic. The network was tested on three different scenarios: high-quality still images, all available video frames and a selected sequence within each video. RESULTS: 57 different patients each with videos of magnification areas of BE (34 dysplasia, 23 NDBE) were included. Performance was evaluated using a leave-one-patient-out cross-validation methodology. 60,174 (39,347 dysplasia, 20,827 NDBE) magnification video frames were used to train the network. The testing set included 49,726 iscan-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 ROC (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 towards real time automated diagnosis

Detection and characterization of colorectal polyps using high-definition white light and i-Scan: Evidence-based consensus recommendations using a modified Delphi process

Background i-Scan is an image enhancement modality, which provides enhanced views of mucosal structures and vascular patterns. Methods A modified Delphi process was used to develop a series of evidence-based statements on the role of high-definition white light (HDWL) and i-Scan for the detection and diagnosis of colorectal neoplasms. Each statement was voted to achieve consensus (i.e. >80% agreement). Results Seven proposed statements achieved consensus: (1) HDWL is recommended rather than standard definition (SD) for detection and diagnosis of colorectal neoplasms; (2) HDWL colonoscopy with i-Scan improves polyp and adenoma detection rates when compared with SD colonoscopy; (3) HDWL + i-Scan is superior to HDWL alone for the optical diagnosis of colorectal neoplasms; (4) HDWL + i-Scan in expert hands meets American Society for Gastrointestinal Endoscopy (ASGE) in the Preservation and Incorporation of Valuable Endoscopic Innovations (PIVI) standards for optical diagnosis of diminutive neoplasms; (5) HDWL + i-Scan in non-expert hands does not meet ASGE PIVI standards for optical diagnosis of diminutive neoplasms; (6) optical diagnosis of polyps with i-Scan has a learning curve and needs systematic training; and (7) the performance of i-Scan for the in vivo diagnosis of colorectal neoplasms is similar to Narrow Band Imaging (NBI) and Fuji Intelligent Chromo Endoscopy (FICE). Conclusions Seven proposed statements on the use of HDWL and i-Scan for the detection and diagnosis of colorectal neoplasms achieved consensus

Endoscopic tissue sampling - Part 2 : Lower gastrointestinal tract. European Society of Gastrointestinal Endoscopy (ESGE) Guideline

1: ESGE suggests performing segmental biopsies (at least two from each segment), which should be placed in different specimen containers (ileum, cecum, ascending, transverse, descending, and sigmoid colon, and rectum) in patients with clinical and endoscopic signs of colitis.Weak recommendation, low quality of evidence. 2: ESGE recommends taking two biopsies from the right hemicolon (ascending and transverse colon) and, in a separate container, two biopsies from the left hemicolon (descending and sigmoid colon) when microscopic colitis is suspected.Strong recommendation, low quality of evidence. 3: ESGE recommends pancolonic dye-based chromoendoscopy or virtual chromoendoscopy with targeted biopsies of any visible lesions during surveillance endoscopy in patients with inflammatory bowel disease. Strong recommendation, moderate quality of evidence. 4: ESGE suggests that, in high risk patients with a history of colonic neoplasia, tubular-appearing colon, strictures, ongoing therapy-refractory inflammation, or primary sclerosing cholangitis, chromoendoscopy with targeted biopsies can be combined with four-quadrant non-targeted biopsies every 10 cm along the colon. Weak recommendation, low quality of evidence. 5: ESGE recommends that, if pouch surveillance for dysplasia is performed, visible abnormalities should be biopsied, with at least two biopsies systematically taken from each of the afferent ileal loop, the efferent blind loop, the pouch, and the anorectal cuff.Strong recommendation, low quality of evidence. 6: ESGE recommends that, in patients with known ulcerative colitis and endoscopic signs of inflammation, at least two biopsies be obtained from the worst affected areas for the assessment of activity or the presence of cytomegalovirus; for those with no evident endoscopic signs of inflammation, advanced imaging technologies may be useful in identifying areas for targeted biopsies to assess histologic remission if this would have therapeutic consequences. Strong recommendation, low quality of evidence. 7: ESGE suggests not biopsying endoscopically visible inflammation or normal-appearing mucosa to assess disease activity in known Crohn's disease.Weak recommendation, low quality of evidence. 8: ESGE recommends that adequately assessed colorectal polyps that are judged to be premalignant should be fully excised rather than biopsied.Strong recommendation, low quality of evidence. 9: ESGE recommends that, where endoscopically feasible, potentially malignant colorectal polyps should be excised en bloc rather than being biopsied. If the endoscopist cannot confidently perform en bloc excision at that time, careful representative images (rather than biopsies) should be taken of the potential focus of cancer, and the patient should be rescheduled or referred to an expert center.Strong recommendation, low quality of evidence. 10: ESGE recommends that, in malignant lesions not amenable to endoscopic excision owing to deep invasion, six carefully targeted biopsies should be taken from the potential focus of cancer.Strong recommendation, low quality of evidence

A new artificial intelligence system successfully detects and localises early neoplasia in Barrett's esophagus by using convolutional neural networks

BACKGROUND AND AIMS: Seattle protocol biopsies for Barrett's Esophagus (BE) surveillance are labour intensive with low compliance. Dysplasia detection rates vary, leading to missed lesions. This can potentially be offset with computer aided detection. We have developed convolutional neural networks (CNNs) to identify areas of dysplasia and where to target biopsy. METHODS: 119 Videos were collected in high-definition white light and optical chromoendoscopy with i-scan (Pentax Hoya, Japan) imaging in patients with dysplastic and non-dysplastic BE (NDBE). We trained an indirectly supervised CNN to classify images as dysplastic/non-dysplastic using whole video annotations to minimise selection bias and maximise accuracy. The CNN was trained using 148,936 video frames (31 dysplastic patients, 31 NDBE, two normal esophagus), validated on 25,161 images from 11 patient videos and tested on 264 iscan-1 images from 28 dysplastic and 16 NDBE patients which included expert delineations. To localise targeted biopsies/delineations, a second directly supervised CNN was generated based on expert delineations of 94 dysplastic images from 30 patients. This was tested on 86 i-scan one images from 28 dysplastic patients. FINDINGS: The indirectly supervised CNN achieved a per image sensitivity in the test set of 91%, specificity 79%, area under receiver operator curve of 93% to detect dysplasia. Per-lesion sensitivity was 100%. Mean assessment speed was 48 frames per second (fps). 97% of targeted biopsy predictions matched expert and histological assessment at 56 fps. The artificial intelligence system performed better than six endoscopists. INTERPRETATION: Our CNNs classify and localise dysplastic Barrett's Esophagus potentially supporting endoscopists during surveillance

Endoscopic management of patients with high-risk colorectal colitis–associated neoplasia:a Delphi study

Background and Aims: Current guidelines recommend endoscopic resection of visible and endoscopically resectable colorectal colitis–associated neoplasia (CAN) in patients with inflammatory bowel disease (IBD). However, patients with high-risk CAN (HR-CAN) are often not amenable to conventional resection techniques, and a consensus approach for the endoscopic management of these lesions is presently lacking. This Delphi study aims to reach consensus among experts on the endoscopic management of these lesions. Methods: A 3-round modified Delphi process was conducted to reach consensus among worldwide IBD and/or endoscopy experts (n = 18) from 3 continents. Consensus was considered if ≥75% agreed or disagreed. Quality of evidence was assessed by the criteria of the Cochrane Collaboration group. Results: Consensus was reached on all statements (n = 14). Experts agreed on a definition for CAN and HR-CAN. Consensus was reached on the examination of the colon with enhanced endoscopic imaging before resection, the endoscopic resectability of an HR-CAN lesion, and endoscopic assessment and standard report of CAN lesions. In addition, experts agreed on type of resections of HR-CAN (20 mm, with or without good lifting), endoscopic success (technical success and outcomes), histologic assessment, and follow-up in HR-CAN. Conclusions: This is the first step in developing international consensus–based recommendations for endoscopic management of CAN and HR-CAN. Although the quality of available evidence was considered low, consensus was reached on several aspects of the management of CAN and HR-CAN. The present work and proposed standardization might benefit future studies

Optical diagnosis of colorectal polyps with Blue Light Imaging using a new international classification

Background Blue Light Imaging (BLI) is a new imaging technology that enhances mucosal surface and vessel patterns. A specific BLI classification was recently developed to enable better characterisation of colorectal polyps (BLI Adenoma Serrated International Classification (BASIC)). The aim of this study was to validate the diagnostic performance of BASIC in predicting polyp histology in experienced and trainee endoscopists. Methods Five experienced and five trainee endoscopists evaluated high-definition white light (HDWL) and BLI images from 45 small polyps to assess baseline accuracy, sensitivity, specificity, and positive and negative predictive values (NPVs) of polyp histology. Each endoscopist was trained with the BLI classification before repeating the exercise. Results were compared pre- and post-training. Results The overall pre-training accuracy improved from 87% to 94%. The sensitivity and NPV of adenoma diagnosis also improved significantly from 79% to 96% and 81% to 95% with BASIC training. This improvement was noted in both groups. The interobserver level of agreement was very good (K = 0.90) in the experienced cohort and good (K = 0.66) in the trainee group post-training. Conclusions BLI is a useful tool for optical diagnosis, and the use of BASIC with adequate training can significantly improve the accuracy, sensitivity and NPV of adenoma diagnosis

Performance measures for small-bowel endoscopy: A European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative

The European Society of Gastrointestinal Endoscopy (ESGE) together with the United European Gastroenterology (UEG) recently developed a short list of performance measures for small-bowel endoscopy (i.e. small-bowel capsule endoscopy and device-assisted enteroscopy) with the final goal of providing endoscopy services across Europe with a tool for quality improvement. Six key performance measures both for small-bowel capsule endoscopy and for device-assisted enteroscopy were selected for inclusion, with the intention being that practice at both a service and endoscopist level should be evaluated against them. Other performance measures were considered to be less relevant, based on an assessment of their overall importance, scientific acceptability, and feasibility. Unlike lower and upper gastrointestinal endoscopy, for which performance measures had already been identified, this is the first time small-bowel endoscopy quality measures have been proposed

Dysplastic Recurrence After Successful Treatment for Early Barrett's Neoplasia:Development and Validation of a Prediction Model

Background & Aims: The combination of endoscopic resection and radiofrequency ablation is the treatment of choice for eradication of Barrett's esophagus (BE) with dysplasia and/or early cancer. Currently, there are no evidence-based recommendations on how to survey patients after successful treatment, and most patients undergo frequent follow-up endoscopies. We aimed to develop and externally validate a prediction model for visible dysplastic recurrence, which can be used to personalize surveillance after treatment. Methods: We collected data from the Dutch Barrett Expert Center Registry, a nationwide registry that captures outcomes from all patients with BE undergoing endoscopic treatment in the Netherlands in a centralized care setting. We used predictors related to demographics, severity of reflux, histologic status at baseline, and treatment characteristics. We built a Fine and Gray survival model with least absolute shrinkage and selection operator penalization to predict the incidence of visible dysplastic recurrence after initial successful treatment. The model was validated externally in patients with BE treated in Switzerland and Belgium. Results: A total of 1154 patients with complete BE eradication were included for model building. During a mean endoscopic follow-up of 4 years, 38 patients developed recurrent disease (1.0%/person-year). The following characteristics were independently associated with recurrence (strongest to weakest predictor): a new visible lesion during treatment phase, higher number of endoscopic resection treatments, male sex, increasing BE length, high-grade dysplasia or cancer at baseline, and younger age. External validation showed a C-statistic of 0.91 (95% confidence interval, 0.86–0.94) with good calibration. Conclusions: This is the first externally validated model to predict visible dysplastic recurrence after successful endoscopic eradication treatment of BE with dysplasia or early cancer. On external validation, our model has good discrimination and calibration. This model can help clinicians and patients to determine a personalized follow-up strategy