High Resolution White Light Endoscopy Research Articles

S1402: Interobserver Variability and Accuracy of High-Resolution Endoscopic Diagnosis for Intestinal Metaplasia Among Experienced and Non-Experienced Endoscopists

Gastric cancer is the second highest cause of cancer-related deaths worldwide. Intestinal metaplasia (IM) has been known to be a premalignant lesion or condition; however there is no gold standard for diagnosing IM. Although several useful techniques combined with the aid of endoscopy have been suggested to accurately diagnose IM, the cost-effectiveness of these modalities has been questioned. Recently, a widely used high-resolution endoscopy made it possible to observe even the mucosal pit pattern and improve diagnostic accuracy of mucosal lesions. The aim of this study was to assess the interobserver variability and accuracy of the high-resolution white-light endoscopy as a diagnostic tool for IM.

Era of Barrett’s surveillance: Does equipment matter?

Barrett's esophagus is a consequence of long standing gastro-esophageal reflux disease and predisposes to the development of esophageal adenocarcinoma. Regular surveillance endoscopies can detect curable early neoplasia in asymptomatic patients, which in turn could improve the prognosis compared to symptomatic cancer. Early neoplastic lesions, which are amenable for local therapy, could be treated endoscopically, avoiding a major surgery. However, in the absence of obvious mucosal lesions, random four quadrant biopsies are done, which is associated with significant sampling error. Newer imaging modalities, such as autofluorescence endoscopy, are helpful in detecting subtle lesions that could be examined in detail with narrow band imaging to characterize and target biopsies. This has the potential benefit of reducing the number of random biopsies with a better yield of dysplasia. Confocal endomicroscopy provides "optical biopsies" and is a valuable tool in targeting biopsies to improve dysplasia detection; however, this is technically challenging. Fuji intelligent chromoendoscopy and I-Scan are recent additions to the imaging armamentarium that have produced notable early results. While all these additional new imaging techniques are promising, a thorough examination by high resolution white light endoscopy after clearing the mucosa with mucolytics should be the minimum standard to improve dysplasia detection during Barrett's surveillance.

Incremental Change in Accuracy of Narrow Band Imaging (NBI) and Acetic Acid Chromoendoscopy (AAC) over High Resolution White Light Endoscopy for Diagnosis of Barrettʼs Esophagus (BE) and Related Neoplasia (BERN)

Incremental Change in Accuracy of Narrow Band Imaging (NBI) and Acetic Acid Chromoendoscopy (AAC) over High Resolution White Light Endoscopy for Diagnosis of Barrettʼs Esophagus (BE) and Related Neoplasia (BERN)

Accuracy and Interobserver Agreement among Experts and Non-Experts for the Diagnosis of Barrettʼs Esophagus (BE) and Related Neoplasia (BERN) using High Resolution White Light Endoscopy with Limited Magnification

Accuracy and Interobserver Agreement among Experts and Non-Experts for the Diagnosis of Barrettʼs Esophagus (BE) and Related Neoplasia (BERN) using High Resolution White Light Endoscopy with Limited Magnification

Combining Autofluorescence Imaging and Narrow-Band Imaging for the Differentiation of Adenomas from Non-Neoplastic Colonic Polyps Among Experienced and Non-Experienced Endoscopists

Endoscopic tri-modal imaging incorporates high-resolution white-light endoscopy (HR-WLE), narrow-band imaging (NBI), and autofluorescence imaging (AFI). Combining these advanced techniques may improve endoscopic differentiation between adenomas and non-neoplastic polyps. In this study, we aimed to assess the interobserver variability and accuracy of HR-WLE, NBI, and AFI for polyp differentiation and to evaluate the combined use of AFI and NBI. First, still images of 50 polyps (22 adenomas; median 3 mm) were randomly displayed to three experienced and four non-experienced endoscopists. All HR-WLE and NBI images were scored for Kudo classification and AFI images for color. Second, the combined AFI and NBI images were assessed using a newly developed algorithm by six additional non-experienced endoscopists. The outcomes measured were interobserver agreement and diagnostic accuracy using histopathology as reference standard. Experienced endoscopists had better interobserver agreement for NBI (kappa=0.77) than for AFI (kappa=0.33), whereas non-experienced endoscopists had better agreement for AFI (kappa=0.58) than for NBI (kappa=0.33). The accuracies of HR-WLE, NBI, and AFI among experienced endoscopists were 65, 70, and 74, respectively. Figures among non-experienced endoscopists were 57, 63, and 77. The algorithm was associated with a significantly higher accuracy of 85% among all observers (P<0.023). These figures were confirmed in the second evaluation study. Non-experienced endoscopists have better interobserver agreement and accuracy for AFI than for HR-WLE or NBI, indicating that AFI is easier to use for polyp differentiation in non-experienced setting. The newly developed algorithm, combining information of AFI and NBI together, had the highest accuracy and obtained equal results between experienced and non-experienced endoscopists.

Narrow-Band Imaging Improves the Detection of Polyps in Patients with Hyperplastic Polyposis Syndrome: A Prospective Randomized Study Comparing Narrow-Band Imaging vs High-Resolution White Light Imaging

Introduction: Hyperplastic polyposis syndrome (HPS) is characterized by the presence of multiple colorectal hyperplastic polyps (HPs). Besides HPs, macroscopically similar sessile serrated adenomas (SSAs) and conventional adenomas are common findings in HPS and are believed to be the pre-malignant polyps. Detection and removal of these high-risk polyps may be an important step in preventing colorectal cancer development in HPS patients. However, polyps in HPS can be difficult to detect due to their unremarkable color and flat shape. Narrow-band imaging (NBI) may improve the detection and differentiation of these polyps. Aims and Methods: To prospectively compare the value of NBI and high-resolution white light endoscopy (WLE) for the detection of polyps in HPS and to assess the value of NBI for the differentiation of these polyps. Consecutive HPS patients undergoing surveillance colonoscopies were included in this study. Each colonic segment was inspected twice, once with WLE and once with NBI, in random order by one experienced endoscopist. Of all detected polyps the size, shape and location was assessed. Kudo pit-pattern analysis was performed in all polyps. Results: In this study, 22 patients were included, in whom a total of 182 polyps were detected: 116 HPs, 42 SSAs and 24 adenomas. The median size of polyps was 5mm (range: 2-20mm). Macroscopically, polyps were classified as flat (60%), sessile (38%) and pedunculated (2%). Proximal location was seen in 54% of HPs, 81% of SSAs and 92% of adenomas. Among patients assigned to inspection with WLE first (n=11), 70 polyps were detected. During subsequent inspection with NBI, 40 additional polyps were visualized. Among patients examined with NBI first (n=11), 65 polyps were detected. Subsequent inspection with WLE rendered 7 additional polyps. The sensitivities of WLE and NBI for overall polyp detection were 64% and 90% respectively (p<0.001). For flat polyps these were 51% and 87% (p<0.001) and for sessile/pedunculated polyps 81% and 96% (ns). The sensitivities of WLE and NBI for HPs was 67% and 90% respectively (p=0.017). For SSAs this was 38% and 86% (p=0.003) and for adenomas 70% and 100% (ns). On NBI, Kudo pit pattern type I-II was seen in 83 (76%) HPs versus 27 (73%) SSAs (ns). Only 6 (25%) adenomas had Kudo type I-II (p<0.001). The accuracy of NBI for discriminating SSAs from HPs was 63% and for differentiating adenomas from HPs this was 75%. Conclusion: NBI significantly improves the detection rate of high-risk SSAs and predominant flat polyps in HPS. Therefore, NBI should be considered as standard practice of care for the endoscopic surveillance of HPS patients.

White light endoscopy, narrow band imaging and chromoendoscopy with magnification in diagnosing colorectal neoplasia

To evaluate the sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of 3 different techniques: high resolution white light endoscopy (WLE), Narrow Band Imaging (NBI) and Chromoendoscopy (CHR), all with magnification in differentiating adenocarcinomas, adenomatous and hyperplastic colorectal polyps. Each polyp was sequentially assessed first by WLE, followed by NBI and finally by CHR. Digital images of each polyp with each modality were taken and stored. Biopsies or polypectomies were then performed followed by blinded histopathological analysis. Each image was blindly graded based on the Kudo's pit pattern (KPP). In the assessment with NBI, the mesh brown capillary network pattern (MBCN) of each polyp was also described. The Sn, Sp, PPV and NPV of differentiating hyperplastic (Type I & II-KPP, Type I-MBCN) adenomatous (Types III, IV-KPP, Type II-MBCN) and carcinomatous polyps (Type V-KPP, Type III-MCBN) was then compared with reference to the final histopathological diagnosis. A total of 50 colorectal polyps (5 adenocarcinomas, 38 adenomas, 7 hyperplastic) were assessed. CHR and NBI [KPP, MBCN or the combined classification (KPP & MBCN)] were superior to WLE in the prediction of polyp histology (P < 0.001, P = 0.002, P = 0.001 and P < 0.001, respectively). NBI, using the MBCN pattern or the combined classification showed higher numerical accuracies compared to CHR, but this was not statistically significant (P = 0.625, 0.250). This feasibility study demonstrated that this combined classification with NBI could potentially be useful in routine clinical practice, allowing the endoscopist to predict histology with higher accuracies using a less cumbersome and technically less challenging method.

Comparison of high-resolution magnification narrow-band imaging and white-light endoscopy in the prediction of histology in Barrett's oesophagus

Objective. To evaluate whether there is any appreciable difference in imaging characteristics between high-resolution magnification white-light endoscopy (WLE-Z) and narrow-band imaging (NBI-Z) in Barrett's oesophagus (BE) and if this translates into superior prediction of histology. Material and methods. This was a prospective single-centre study involving 21 patients (75 areas, corresponding NBI-Z and WLE-Z images) with BE. Mucosal patterns (pit pattern and microvascular morphology) were evaluated for their image quality on a visual analogue scale (VAS) of 1–10 by five expert endoscopists. The endoscopists then predicted mucosal morphology based on four subtypes which can be visualized in BE. Type A: round pits, regular microvasculature; type B: villous/ridge pits, regular microvasculature; type C: absent pits, regular microvasculature; type D: distorted pits, irregular microvasculature. The sensitivity (Sn), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV) and accuracy (Acc) were then compared with the final histopathological analysis and the interobserver variability calculated. Results. The overall pit and microvasculature quality was significantly higher for NBI-Z, pit: NBI-Z=6, WLE-Z=4.5, p<0.001; microvasculature: NBI-Z=7.3, WLE-Z=4.9, p<0.001. This translated into a superior prediction of histology (Sn: NBI-Z: 88.9, WLE-Z: 71.9, p<0.001). For the prediction of dysplasia, NBI-Z was superior to WLE-Z (χ2=10.3, p<0.05). The overall kappa agreement among the five endoscopists for NBI-Z and WLE-Z, respectively, was 0.59 and 0.31 (p<0.001). Conclusions. NBI-Z is superior to WLE-Z in the prediction of histology in BE, with good reproducibility. This novel imaging modality could be an important tool for surveillance of patients with BE.

Mucosal morphology in Barrett’s esophagus: interobserver agreement and role of narrow band imaging

We have recently proposed a classification of mucosal morphology in Barrett's esophagus based on three criteria: regularity of mucosal pattern, regularity of vascular pattern, and presence of abnormal blood vessels. We aimed to evaluate the interobserver agreement with the proposed mucosal morphology classification and to assess the additional value of narrow band imaging (NBI) over high resolution white light endoscopy (HR-WLE). Five international experts in the field of Barrett's imaging and seven community endoscopists with no expertise in this field independently evaluated magnified still images from 50 areas, obtained with HR-WLE and NBI, in Barrett's esophagus patients. Visual analogue scales (VAS) were used for scoring imaging quality. Interobserver agreement for mucosal morphology and yield for identifying early neoplasia were assessed. Imaging qualities of NBI were rated more highly than HR-WLE, when evaluated separately as well as in a side-by-side comparison. The interobserver agreement ranged from 0.40 to 0.56 and did not significantly differ between expert and non-expert endoscopists. The overall yield for correctly identifying images of early neoplasia was 81 % for HR-WLE, 72 % for NBI and 83 % for HR-WLE + NBI, with no significant difference between experts and non-experts. Interobserver agreement for the classification of mucosal morphology was moderate. Although NBI was rated more highly than HR-WLE for imaging quality, this did not result in improved interobserver agreement or increased yield for identifying early neoplasia in Barrett's esophagus. This applied to non-expert as well as expert endoscopists.

This Month in Gastroenterology

This Month in Gastroenterology

Chromoendoscopy and Narrow-Band Imaging Compared With High-Resolution Magnification Endoscopy in Barrett’s Esophagus

The aim of this study was to compare magnified still images obtained with high-resolution white light endoscopy, indigo carmine chromoendoscopy, acetic acid chromoendoscopy, and narrow-band imaging to determine the best technique for use in Barrett's esophagus. We obtained magnified images from 22 areas with the 4 aforementioned techniques. Seven endoscopists with no specific expertise in Barrett's esophagus or advanced imaging techniques and 5 international experts in this field evaluated these 22 areas for overall image quality, mucosal image quality, and vascular image quality. In addition, the regularity of mucosal and vascular patterns and the presence of abnormal blood vessels were evaluated, and this was correlated with histology. The interobserver agreement for the 3 features of mucosal morphology with white light images ranged from kappa = 0.51 (95% confidence interval [CI]: 0.46-0.55) to kappa = 0.53 (95% CI: 0.50-0.57) for all observers, from kappa = 0.43 (95% CI: 0.33-0.54) to kappa = 0.53 (95% CI: 0.41-0.64) for experts, and from kappa = 0.51 (95% CI: 0.15-0.33) to kappa = 0.64 (95% CI: 0.58-0.70) for nonexperts. The interobserver agreement in these groups did not improve by adding one of the enhancement techniques. The yield for identifying early neoplasia with white light images was 86% for all observers, 90% for experts, and 84% for nonexperts. The addition of enhancement techniques did not improve the yield neoplasia. The addition of indigo carmine chromoendoscopy, acetic acid chromoendoscopy, or narrow-band imaging to white light images did not improve interobserver agreement or yield identifying early neoplasia in Barrett's esophagus.

Endoscopic Trimodality Imaging (ETMI) for the Detection and Classification of Colonic Polyps

Background and Aim: Endoscopic detection and removal of colonic adenomas prevents the development of colorectal cancer (CRC). During standard colonoscopy 13-26% of small adenomas are missed and 17-40% of detected polyps are non-adenomatous. A new endoscopic trimodality imaging (ETMI) system has been developed, incorporating high resolution white light endoscopy (WLE), autofluorescence imaging (AFI) and narrow band imaging (NBI). In this ongoing randomized cross-over study we are assessing the value of ETMI for the detection and classification of colonic polyps in patients at increased risk for adenomas.

Endoscopic Trimodality Imaging (ETMI) for Detection and Classification of Neoplasia in Patients with Longstanding Ulcerative Colitis

Background and Aims: Patients with longstanding ulcerative colitis (UC) are recommended to undergo regular colonoscopic surveillance with targeted and random biopsies for the detection of neoplasia. However, the sensitivity of this method is low. Recently, Endoscopic TriModality Imaging (ETMI) has been developed, incorporating high resolution White Light Endoscopy (WLE), AutoFluorescence Imaging (AFI) and Narrow Band Imaging (NBI). We performed a pilot study, in which we assessed the feasibility and accuracy of ETMI and compared AFI with WLE for the detection of neoplasia in patients with longstanding UC. Methods: Consecutive UC patients, scheduled for surveillance colonoscopy, were invited to participate in this study. During withdrawal, each colonic segment was inspected twice; once with WLE and once with AFI, in randomized order. All detected lesions were subsequently inspected by NBI for assessing Kudo classification. Hereafter, targeted as well as random biopsies were taken. The histology of the biopsies was used as the gold standard. Results: Informed consent was obtained from 58 patients. Three patients had to be excluded because of insufficient colon preparation and 5 because of active inflammation despite a low disease activity index. Among 25 patients randomized to start with AFI, 8 neoplastic lesions were found with AFI (in 4 patients). Second inspection with WLE revealed 1 extra neoplastic lesion (1 additional patient). Among 25 patients examined with WLE first, 4 neoplastic lesions were found with WLE (2 patients). Subsequent AFI yielded 3 additional neoplastic lesions (2 extra patients). A mean number of 40 (SD 7) random biopsies was taken per patient, revealing neoplasia in 4 biopsies (one additional patient with neoplasia in whom WLE and subsequent AFI were both normal). The sensitivity of AFI and WLE for the detection of patients with neoplasia was 75% and 50% respectively (p = 0.580). The positive predictive values were 21% and 12% respectively (p = 0.470). The Kudo classification based on NBI for predicting histological outcome of detected lesions had a sensitivity of 75%, specificity of 80%, positive predictive value of 43% and negative predictive value (NPV) of 94%. A detected lesion which was green with AFI never revealed neoplasia. Conclusion: The use of ETMI in patients with UC is feasible, provided that the colon is properly prepared and the mucosa is not actively inflamed. In this pilot study, the sensitivity of AFI seems to be better than WLE for the detection of neoplasia, but the small sample size of our study prevents drawing any firm conclusion. Once a lesion has been detected, ETMI has a high NPV for histology.

Night Vision Goggles for Surveillance of Barrett’s Esophagus: A Paradigm Shift is Coming!

Night Vision Goggles for Surveillance of Barrett’s Esophagus: A Paradigm Shift is Coming!