Narrow-band Imaging Colonoscopy Research Articles

Benchmarking Polyp Segmentation Methods in Narrow-Band Imaging Colonoscopy Images.

In recent years, there has been significant progress in polyp segmentation in white-light imaging (WLI) colonoscopy images, particularly with methods based on deep learning (DL). However, little attention has been paid to the reliability of these methods in narrow-band imaging (NBI) data. NBI improves visibility of blood vessels and helps physicians observe complex polyps more easily than WLI, but NBI images often include polyps with small/flat appearances, background interference, and camouflage properties, making polyp segmentation a challenging task. This paper proposes a new polyp segmentation dataset (PS-NBI2K) consisting of 2,000 NBI colonoscopy images with pixel-wise annotations, and presents benchmarking results and analyses for 24 recently reported DL-based polyp segmentation methods on PS-NBI2K. The results show that existing methods struggle to locate polyps with smaller sizes and stronger interference, and that extracting both local and global features improves performance. There is also a trade-off between effectiveness and efficiency, and most methods cannot achieve the best results in both areas simultaneously. This work highlights potential directions for designing DL-based polyp segmentation methods in NBI colonoscopy images, and the release of PS-NBI2K aims to drive further development in this field.

Multi-Classification of Polyps in Colonoscopy Images Based on an Improved Deep Convolutional Neural Network

Achieving accurate classification of colorectal polyps during colonoscopy can avoid unnecessary endoscopic biopsy or resection. This study aimed to develop a deep learning model that can automatically classify colorectal polyps histologically on white-light and narrow-band imaging (NBI) colonoscopy images based on World Health Organization (WHO) and Workgroup serrAted polypS and Polyposis (WASP) classification criteria for colorectal polyps. White-light and NBI colonoscopy images of colorectal polyps exhibiting pathological results were firstly collected and classified into four categories: conventional adenoma, hyperplastic polyp, sessile serrated adenoma/polyp (SSAP) and normal, among which conventional adenoma could be further divided into three sub-categories of tubular adenoma, villous adenoma and villioustublar adenoma, subsequently the images were re-classified into six categories. In this paper, we proposed a novel convolutional neural network termed Polyp-DedNet for the four- and six-category classification tasks of colorectal polyps. Based on the existing classification network ResNet50, Polyp-DedNet adopted dilated convolution to retain more high-dimensional spatial information and an Efficient Channel Attention (ECA) module to improve the classification performance further. To eliminate gridding artifacts caused by dilated convolutions, traditional convolutional layers were used instead of the max pooling layer, and two convolutional layers with progressively decreasing dilation were added at the end of the network. Due to the inevitable imbalance of medical image data, a regularization method DropBlock and a Class-Balanced (CB) Loss were performed to prevent network overfitting. Furthermore, the 5-fold cross-validation was adopted to estimate the performance of Polyp-DedNet for the multi-classification task of colorectal polyps. Mean accuracies of the proposed Polyp-DedNet for the four- and six-category classifications of colorectal polyps were 89.91% ± 0.92% and 85.13% ± 1.10%, respectively. The metrics of precision, recall and F1-score were also improved by 1%~2% compared to the baseline ResNet50. The proposed Polyp-DedNet presented state-of-the-art performance for colorectal polyp classifying on white-light and NBI colonoscopy images, highlighting its considerable potential as an AI-assistant system for accurate colorectal polyp diagnosis in colonoscopy.

Optical diagnosis by near-focus versus normal-focus narrow band imaging colonoscopy in colorectal polyps based on combined NICE and WASP classification: a randomized controlled trial.

Background/AimsNarrow Band Imaging (NBI) International Colorectal Endoscopic (NICE) and Workgroup Serrated Polyps and Polyposis (WASP) classifications were developed for optical diagnosis of neoplastic and sessile serrated polyps, respectively. Near-focus NBI with NICE combined with WASP criteria for optical diagnosis of colonic polyps has not yet been evaluated. We aimed to compare the accuracy of near-focus NBI (group A) with normal-focus NBI (group B) in real-time optical diagnosis of colorectal polyps using combined NICE and WASP criteria. MethodsAmong 362 patients, 118 with 227 polyps were recruited. Groups A and B included 62 patients with 130 polyps (three lost polyps) and 56 patients with 106 polyps (six lost polyps), respectively. Optical diagnoses were compared with pathological reports. ResultsThe accuracy of optical diagnosis of neoplastic polyps in groups A and B was not significantly different (76% vs. 71%, p=0.52). WASP criteria provided all false positive diagnoses of sessile polyps as serrated polyps in 31 (16.2%) patients. ConclusionsNear-focus NBI was not superior to normal-focus NBI in optical diagnostics of neoplastic polyps using NICE criteria. In our study, WASP classification yielded all false positives in the diagnosis of sessile serrated adenomas/polyps. Routine real-life optical diagnosis of polyps is still unadvisable.

Predicting Histological Healing and Recurrence in Ulcerative Colitis by Assessing Mucosal Vascular Pattern Under Narrow-Band Imaging Endoscopy.

This study investigated the predictive value of narrow-band imaging (NBI) endoscopic staging of different mucosal vascular patterns (MVPs) in patients with ulcerative colitis (UC) for histological healing or clinical recurrence of patients with UC. A total of 124 patients with UC in clinical remission attending the First Affiliated Hospital of Weifang Medical College were included in the study and underwent NBI colonoscopy. Inflammatory activity was assessed in the intestine using the Mayo endoscopic score (MES) and the MVP. Mucosal inflammation was histologically graded using the Nancy index (NI). The colons of 124 patients with UC were staged according to NBI endoscopic MVP staging criteria. The differences between NBI colonoscopy MVP typing and white light endoscopic MES in assessing histological healing (HH) were statistically significant (p < 0.001), and there was a moderate correlation between MES and the degree of HH (r = 0.471, p < 0.001). In addition, there was a significant correlation between the severity of mucosal activity determined by white light endoscopy (WLE) and MVP staging (r = 0.811, p < 0.001). The differences between NBI endoscopic MVP staging and white light endoscopic MES in assessing UC recurrence were statistically significant (p < 0.001). Spearman's correlation analysis showed a moderate correlation between NBI endoscopic MVP staging and clinical recurrence. NBI endoscopic MVP staging can predict HH and clinical recurrence status better than WLE.

Is barium enema examination negligible for the management of colorectal cancer? Comparison with conventional colonoscopy and magnifying colonoscopy.

The aim of this investigation was to evaluate the clinical value of barium enema (BE) examination for the management of colorectal epithelial neoplasms. We reviewed the colonoscopy records at our institution from 2014 to 2019 and identified cases of endoscopically or surgically resected colorectal epithelial neoplasms evaluated by BE, conventional colonoscopy, magnifying narrow-band imaging colonoscopy (M-NBI), and magnifying chromoendoscopy (MCE). The yield of each modality for the diagnosis of massively submucosal invasive (mSM) colorectal cancer was evaluated by a receiver-operating characteristic analysis including the area under the curve (AUC). We analyzed the records of 105 patients (17 adenomas, 53 high-grade dysplasias (HGDs), and 35 cancers). Smooth surface, irregularity in depression, and eccentric deformity on the profile view with BE were observed more frequently in mSM cancers than adenomas/HGDs/slightly submucosal invasive cancers (p < 0.01). The AUC of BE was 0.8355, the value of which was not different from the other three modalities (conventional colonoscopy 0.7678; M-NBI 0.7835; MCE 0.8376). Although the specificity, PPV, and accuracy of BE were lower than those of M-NBI and MCE, the sensitivity and NPV of BE were the highest among the four types of examinations. BE is still available and may serve as a supplementary modality for the diagnosis of mSM cancers.

Predicting Mucosal Proliferation in Ulcerative Colitis by Assessing Mucosal Vascular Pattern Under Narrow Band Imaging Colonoscopy.

Proliferative abnormalities are believed to represent an early phase of colorectal carcinogenesis. Narrow band imaging (NBI) colonoscopy allows visual assessment of the mucosal vascular pattern (MVP) without dyeing. The aim of this study was to investigate the predictive value of MVP for mucosal proliferation in ulcerative colitis (UC). A total of 119 colorectal lesions were analyzed from 42 patients with UC who underwent NBI colonoscopy. Both the MVP and the Mayo endoscopic score (MES) were assessed. The mucosal inflammation was histologically graded using a colitis score. The proliferation marker Ki-67 was assessed by immunohistochemical staining. The results showed that MVP correlated well with the MES (r = 0.796, P < .001). There was moderate correlation between the distribution of Ki-67 staining and MVP (r = 0.492, P < .001), and the Ki-67 labeling index increased with the orderly patterns of MVP (P < .001). An expansion of Ki-67 staining upward from the crypt base may be caused by active inflammation. MVP based on NBI colonoscopy can predict mucosal proliferation which is associated with inflammation in patients with UC.

Can Vascular Endothelial Growth Factors and CD34 Expression Implement NICE (Narrow-Band Imaging International Colorectal Endoscopic) Classification in Colorectal Polypoid Lesion Diagnosis?

Background: Vascular endothelial growth factor (VEGF) is a subfamily of growth factors involved in angiogenesis; CD34+ cells are normally found in endothelial progenitor cells and endothelial cells of blood vessels. Colonic adenomatous polyps may not always be completely removable endoscopically, and a preoperative diagnosis might still be necessary. The aim of the study was to evaluate whether VEGF-A, VEGF-C and CD34 mRNA expression along colorectal carcinogenesis steps can implement NICE (Narrow-Band Imaging International Colorectal Endoscopic) classification in the diagnosis of malignancy in colorectal polypoid lesions. Methods: Seventy-one subjects with colonic adenoma or cancer who underwent screening narrow-band imaging (NBI) colonoscopy were prospectively enrolled in the MICCE1 project (Treviso center). Polyps were classified according to the NICE classification. Real-time RT-PCR for VEGF-A, VEGF-C and CD34 mRNA expression was performed. Nonparametric statistics, receiver-operating characteristic curve analysis and logistic multiple regression analysis were used. Results: VEGF-A and CD34 mRNA expression was significantly higher in sessile adenomas than in polypoid ones (p < 0.001 and p = 0.01, respectively). VEGF-A, VEGF-C and CD34 mRNA expression was significantly higher in adenocarcinoma than in adenoma (p = 0.01, p = 0.01 and p = 0.01, respectively). The accuracy of VEGF-A, VEGF-C and CD34 mRNA expression for prediction of malignancy was 0.79 (95% CI 0.65–0.90), 0.81 (95% CI 0.66–0.91) and 0.80 (95% CI 0.65–0.90), respectively, while the accuracy of the NICE classification was 0.85 (95% CI 0.72–0.94). The determination coefficient R², which indicates the amount of the variability explained by a regression model, for NICE classification alone was 0.24 (p < 0.001). A regression model that included NICE classification and VEGF-C mRNA expression showed an R² = 0.39 as well as a model including NICE classification and CD34 mRNA levels. Conclusions: This study demonstrated that VEGF-C and CD34 mRNA levels might be useful to stratify colorectal polyps in different risk of progression classes by implementing the accuracy of the NICE classification. Studies on in vivo detection of these markers are warranted.

ESTUDO DA ACURÁCIA NA AVALIAÇÃO DOS PÓLIPOS ENTRE A COLONOSCOPIA CONVENCIONAL, CROMOSCOPIA COM NARROW-BAND IMAGING E CROMOSCOPIA COM ÍNDIGO CARMIN

Introdução: As técnicas de cromoendoscopia aperfeiçoaram a acurácia na identificação de pólipos colorretais e contribuíram para a padronização de classificações. A classificação de Kudo avaliam as criptas intestinais através de corantes, enquanto que Japan NBI Expert Team avalia principalmente o padrão vascular da mucosa intestinal por meio da cromoendoscopia eletrônica. Ambos auxiliam na acurácia diagnóstica e rastreamento de câncer colorretal. Objetivo: Comparar a eficácia da colonoscopia convencional, cromoendoscopia com índigo e colonoscopia com Narrow-Band Imaging na acurácia diagnóstica de pólipos colorretais neoplásicos e não-neoplásicos. Materiais e métodos: Foram realizadas 119 polipectomias nos pólipos colorretais pequenos em centro especializado. As imagens dos pólipos foram avaliadas por um médico endoscopista experiente, que avaliou os padrões vasculares e superfícies dos pólipos de acordo com as classificações de Kudo e Japan NBI Expert Team, conforme o método utilizado (corante, Narrow-Band Imaging ou dedução em colonoscopia convencional). Os resultados das classificações foram comparados com o exame histológico. Conclusão: A colonoscopia com índigo, a colonoscopia com NBI e a colonoscopia convencional possuem eficácia no diagnóstico endoscópico, sendo a cromoscopia com índigo a de maior acurácia. Todavia, o diagnóstico endoscópico não deve ser exclusivo, sendo complementado pela avaliação histológica.

Narrow-Band Imaging Colonoscopy to Assess Mucosal Angiogenesis in Ulcerative Colitis.

Background and Aim It has been documented that angiogenesis is a largely unstudied component of the pathogenesis of ulcerative colitis (UC). Under narrow-band imaging (NBI) colonoscopy, the mucosal vascular pattern (MVP) can be visualized without the use of dyes. The aim of this study was to assess the grade of mucosal angiogenesis based on the MVP in UC. Methods A total of 119 colorectal segments taken from 42 patients with UC were observed using NBI colonoscopy. The MVP was classified as follows: clear, obscure, or absent. Quantification of the degree of inflammation was performed using histological colitis scoring. Potent angiogenic activity was assessed by immunohistochemical staining for vascular endothelial growth factor (VEGF). Microvascular density was assessed using vessel counts as revealed by CD31 staining. The correlation between the MVP and histological grades of inflammation and angiogenesis was evaluated. Results The MVP correlated well with the histological severity of inflammation. We also demonstrated an increasing level of microvascular density and VEGF staining along with the ordered types of MVPs. In addition, a statistically strong association existed between microvascular density and VEGF staining. Conclusions NBI colonoscopy might be a useful tool for the in vivo assessment of the grade of mucosal angiogenesis in UC.

Prospective diagnostic study on the use of narrow-band imaging on suspicious lesions during colonoscopy examination.

Colonoscopy is the gold standard to detect colorectal neoplasm. Narrow-band imaging (NBI) has a good diagnostic accuracy to differentiate between neoplastic and non-neoplastic colorectal lesions. This study explores the diagnostic validity of NBI colonoscopy as well as its associated factors related to neoplastic and non-neoplastic colorectal lesions. This study enrolled 100 patients in a single-center tertiary teaching hospital. Patients presented for screening colonoscopy, and those with suspicious colorectal lesions were included in this study. During colonoscopy, the most suspicious lesion in each patient was analyzed using the NBI system based on Sano's classification. Each lesion was biopsied for histopathological analysis, the gold standard. Endoscopic images were captured electronically. The sensitivity, specificity, and diagnostic accuracy of NBI colonoscopy were assessed. Other associated factors related to neoplastic and non-neoplastic lesions were analyzed accordingly. The sensitivity and specificity of the NBI were 88.2% and 71.9%, respectively. The area under the receiver-operator curve was 0.801, indicating that NBI has a good ability to differentiate between disease and non-disease. There are significant associations between histopathological examination outcomes and both presenting symptoms, especially weight loss, and lesion site, even after other variables were controlled (P < 0.05). The NBI system in colonoscopy was capable of distinguishing neoplastic from non-neoplastic colorectal lesions. It indicates an acceptable level of agreement with histopathology, the gold standard. However, the role of NBI in screening and surveillance in Malaysia still needs further evaluation and exploration.

Association between white opaque substance under magnifying colonoscopy and lipid droplets in colorectal epithelial neoplasms.

AIMTo examine the association between white opaque substance (WOS) and histologically verified lipid droplets in colorectal epithelial neoplasms.METHODSWe reviewed colonoscopy records at our institution from 2014 to 2016 and identified cases of endoscopically or surgically resected colorectal epithelial neoplasms observed by magnifying narrow-band imaging (M-NBI) colonoscopy. Immunohistochemistry was used to stain tumors with a monoclonal antibody specific to adipophilin as a marker of lipids. The expression and distribution of adipophilin were compared between WOS-positive and WOS-negative lesions and among tumors classified by histologic type and depth of invasion.RESULTSUnder M-NBI colonoscopy, 81 lesions were positive for WOS and 48 lesions were negative for WOS. The rate of adipophilin expression was significantly higher in WOS-positive lesions (95.1%) than in WOS-negative lesions (68.7%) (P = 0.0001). The incidence of deep adipophilin expression was higher in WOS-positive lesions (24.7%) than in WOS-negative lesions (4.2%) (P = 0.001). The incidence of deep expression was predominant among cancers with massive submucosal invasion (62.5%) compared to adenoma (7.2%) and high-grade dysplasia or cancers with slight submucosal invasion (12.7%) (P = 0.0001).CONCLUSIONThe distribution of lipid droplets may be closely associated with the visibility of WOS under M-NBI colonoscopy, and with histologic grade and depth of tumor invasion.

The role of narrow band imaging in colorectal polyp detection.

Colonoscopic detection and removal of polyps represent the most important prevention method for colorectal cancer. We aimed to investigate the diagnostic yield of narrow band imaging (NBI) colonoscopy for polyp detection compared with standard colonoscopy. In this prospective study, 505 patients that underwent total colonoscopy were randomized into two groups: 226 patients in NBI group and 279 in non-NBI group (standard colonoscopy). The primary endpoints were polyp detection rate (PDR) and adenoma detection rate (ADR) in both groups. Polyps detected with NBI technique were characterized according to the NBI International Colorectal Endoscopic (NICE) classification. The total number of polyps detected in NBI group was significantly higher compared with non-NBI group (325 polyps in 226 patients versus 189 polyps in 279 patients, respectively). PDR in NBI group was 55.3%, versus 43.3% in non-NBI group. ADR in NBI group was significantly higher compared with non-NBI group (35.3% versus 20%, respectively). The proportion of detected adenomas in the left-sided colon was significantly higher in NBI group (72.8% versus 61.06% in non-NBI group), which was related to an increased number of small adenomas detected in NBI group. Also, in NBI group, a significant number of flat adenomas were detected (28 versus 9 in non-NBI group). A total of 147 (45.2%) polyps were classified according to the NICE classification, and showed a good correlation with histological analysis. In conclusion, this study demonstrated increased PDR and ADR for NBI colonoscopy. A good correlation between the NICE classification and histological analysis was also observed.

Narrow Band Imaging Can Be Used for Anastomotic Assessment

Background: Anastomotic leak is the most dreaded complication and it accounts for one third of post-operative deaths in colorectal surgery. There is strong need of research in this field in order to reduce anastomotic leak rate. If there was a test available to signify probability of leak at the time of surgery, it would potentially avoid a leak at a later date. Aim: We propose that intra operative use of narrow band imaging colonoscopy in left sided colonic anastomosis can predict and detect anastomosis related problems, problems i.e. vascularity, anastomotic lumen patency and rigidness of anastomosis which in turn lead to correction at the time of surgery resulting in significant decrease in anastomotic leak rate associated with morbidity and mortality. Methodology: A pilot, single blind, prospective, randomised controlled trial. Aim is to divide patient in 2 groups, containing 15 patients in each group. One group will be assessed by intra-operative NBI colonoscopy and other with standard technique. Analysis: This will be performed using SPSS with the help of statistician. Significance: This area of research is particularly important because it improves survival by reducing morbidity and mortality associated with anastomotic leak. If a leak is avoided then it does not only mean early recovery but it also saves NHS in terms of ICU care, NHS bed, inpatient nursing care and home help, unfortunately all required if leak is to occur. As a result, this research will have better financial implication with significantly improve patient care.

A Randomized Controlled Clinical Study Comparing the Diagnostic Accuracy of the Histologic Prediction for Colorectal Polyps Depending on the Use of Either Magnified or Nonmagnified Narrow Band Imaging.

Background/Aims:The aim of this study was to compare the diagnostic capabilities of narrow band imaging (NBI) colonoscopy with and without optical magnification in differentiating neoplastic from nonneoplastic colorectal polyps.Methods:Between April 2012 and March 2013, 122 patients with colorectal polyps detected by using diagnostic conventional colonoscopy were prospectively enrolled. A total of 236 polyps were evaluated with NBI, in vivo in real time during therapeutic colonoscopy, by one experienced endoscopist. Whether magnification was used or not was determined by randomization. After an in vivo real-time endoscopic prediction of histology, all lesions were endoscopically excised. Surgical pathologic reports were used as the criterion standards. The sensitivity (Sn), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) of identifying neoplastic polyps were calculated.Results:A total of 236 lesions with an average size of 5.6 mm in 122 patients were assessed (159 neoplastic, 77 nonneoplastic). The Sn, Sp, PPV, and NPV in differentiating neoplastic from nonneoplastic lesions with the magnified NBI were 97.5%, 83.3%, 94.0%, and 92.6%, respectively, whereas those of the nonmagnified NBI group were 97.5%, 85.1%, 91.7%, and 95.2%, respectively.Conclusions:Nonmagnified NBI colonoscopy distinguishes neoplastic from nonneoplastic colorectal polyps as accurately as does magnified NBI colonoscopy.

Narrow Band Imaging as an Efficient and Economical Tool in Diagnosing Colorectal Polyps.

Narrow Band Imaging as an Efficient and Economical Tool in Diagnosing Colorectal Polyps.

Significance of a white opaque substance under magnifying narrow-band imaging colonoscopy for the diagnosis of colorectal epithelial neoplasms

The aim of this study was to examine the significance of a white opaque substance (WOS) found on magnifying narrow-band imaging (M-NBI) for the diagnosis of colorectal neoplastic lesions. We retrospectively reviewed colonoscopy records from 2006 to 2012 at our institution and identified cases of endoscopically or surgically resected colorectal epithelial neoplasms observed by M-NBI colonoscopy. The colonoscopic and histologic characteristics of the lesions were compared between WOS-positive and WOS-negative lesions. We further classified the WOS as regular or irregular and compared the histologic characteristics between the two types of lesions. There were 105 WOS-positive lesions and 451 WOS-negative lesions. The former were subdivided into lesions with regular and irregular WOS. The incidence of high-grade dysplasia or carcinoma was significantly higher in WOS-positive lesions (61.9%) than in WOS-negative lesions (28.6%) (P < .05). Among the WOS-positive lesions, massive submucosal invasion was more frequent in lesions with irregular WOS (82.4%) than in those with regular WOS (1.4%) (P < .05). Among cancers with massive submucosal invasion, lymph node metastasis was more frequent in cancers with irregular WOS (17.4%) than in those with regular WOS or without the WOS (0%) (P < .05). A WOS in colorectal neoplasms may be an optical marker for high-grade dysplasia and cancer. An irregular WOS may be indicative of massive submucosal invasion and lymph node metastasis.

Narrow-band imaging versus white light for the detection of proximal colon serrated lesions: a randomized, controlled trial

The value of narrow-band imaging (NBI) for detecting serrated lesions is unknown. To assess NBI for the detection of proximal colon serrated lesions. Randomized, controlled trial. Two academic hospital outpatient units. Eight hundred outpatients 50 years of age and older with intact colons undergoing routine screening, surveillance, or diagnostic examinations. Randomization to colon inspection in NBI versus white-light colonoscopy. The number of serrated lesions (sessile serrated polyps plus hyperplastic polyps) proximal to the sigmoid colon. The mean inspection times for the whole colon and proximal colon were the same for the NBI and white-light groups. There were 204 proximal colon lesions in the NBI group and 158 in the white light group (P = .085). Detection of conventional adenomas was comparable in the 2 groups. Lack of blinding, endoscopic estimation of polyp location. NBI may increase the detection of proximal colon serrated lesions, but the result in this trial did not reach significance. Additional study of this issue is warranted. ( NCT01572428.).

Next-generation narrow band imaging system for colonic polyp detection: a prospective multicenter randomized trial.

Previous studies have yielded conflicting results on the colonic polyp detection rate with narrow-band imaging (NBI) compared with white-light imaging (WLI). We compared the mean number of colonic polyps detected per patient for NBI versus WLI using a next-generation NBI system (EVIS LUCERA ELITE; Olympus Medical Systems) used with standard-definition (SD) colonoscopy and wide-angle (WA) colonoscopy. this study is a 2 × 2 factorial, prospective, multicenter randomized controlled trial. this study was conducted at five academic centers in Japan. patients were allocated to one of four groups: (1) WLI with SD colonoscopy (H260AZI), (2) NBI with SD colonoscopy (H260AZI), (3) WLI with WA colonoscopy (CF-HQ290), and (4) NBI with WA colonoscopy (CF-HQ290). the mean numbers of polyps detected per patient were compared between the four groups: WLI with/without WA colonoscopy and NBI with/without WA colonoscopy. Of the 454 patients recruited, 431 patients were enrolled. The total numbers of polyps detected by WLI with SD, NBI with SD, WLI with WA, and NBI with WA were 164, 176, 188, and 241, respectively. The mean number of polyps detected per patient was significantly higher in the NBI group than in the WLI group (2.01 vs 1.56; P = 0.032). The rate was not higher in the WA group than in the SD group (1.97 vs 1.61; P = 0.089). Although WA colonoscopy did not improve the polyp detection, next-generation NBI colonoscopy represents a significant improvement in the detection of colonic polyps.

Real-time optical diagnosis for diminutive colorectal polyps using narrow-band imaging: the VALID randomised clinical trial

BackgroundDiminutive (≤5 mm) colorectal polyps are common, and overwhelmingly benign. Routinely, after polypectomy, they are examined pathologically to determine the surveillance intervals. Advances in equipment and techniques, such as narrow-band...

Accuracy of in vivo colorectal polyp discrimination by using dual-focus high-definition narrow-band imaging colonoscopy

Discriminating neoplastic from non-neoplastic polyps can significantly reduce the cost of colonoscopy. The American Society for Gastrointestinal Endoscopy (ASGE) recently set threshold levels for optical diagnostic accuracy to be acceptable for clinical use. In this study, we compare a novel colonoscope capable of dual-focus imaging with standard colonoscopy with respect to the ASGE guidelines. An academic medical center ambulatory surgical center. Patients at average risk were randomized to standard colonoscopy (Olympus CF-H180 and Exera II 180 colonoscopes, Olympus America, Center Valley, Pa) or dual-focus colonoscopy (Olympus CF-HQ190 and Exera III 190 colonoscopes, Olympus America). All polyps were given an optical diagnosis and compared with histology. A total of 600 patients were consented and 522 completed all aspects of the procedure. A total of 927 polyps were analyzed. Optical diagnostic accuracy was 79% (95% confidence interval, 74%-83%) for the 190 and 77% (95% confidence interval, 73%-81%) for the 180 colonoscope. Adenoma detection rates were also similar between the 2 groups (50% for the 190 vs 52% for the 180 colonoscope). For small distal rectosigmoid polyps with a high confidence diagnosis, the negative predictive value for adenoma was 96% (range 89%-99%) for the 180 in the narrow-band imaging (NBI) mode and 97% (range 88%-99%) for the 190 colonoscope in NBI mode. Agreement of surveillance intervals by using optical diagnosis was 94% to 95% for all modalities (180 and 190 colonoscopes, white light imaging, NBI). Our study evaluated the accuracy of the 180 and 190 colonoscopes at a center with already-established expertise in endoscopic imaging. Both traditional and new dual-focus colonoscopes provide highly accurate optical polyp discrimination. There was no difference between the 2 systems in terms of discrimination or adenoma detection. Both systems are consistent with ASGE guidelines for optical diagnosis of selected colorectal polyps without histological confirmation.