Narrow-band imaging in the diagnosis of colorectal mucosal lesions: a pilot study

Feasibility of observational screening colonoscopy followed by deferred polypectomy

BACKGROUND AND AIM

With the increasing necessity of colorectal cancer screening, observational screening colonoscopy during which only endoscopic observation and diagnosis is performed is worth consideration. However, whether detected lesions can be correctly identified at secondary colonoscopy performed for polypectomy is unclear. Further, whether new neoplastic lesions can be detected at secondary colonoscopy has not been fully examined. This study was performed to investigate the detectability of adenomatous polyps and advanced colorectal neoplasia (ACN) at secondary colonoscopy.

METHODS

Data were analyzed from individuals who underwent initial observational screening colonoscopy followed by secondary colonoscopy for polypectomy. The proportion of correct detection at secondary colonoscopy of the lesions detected at initial colonoscopy was assessed. The number and characteristics of lesions that were newly detected at secondary colonoscopy were also evaluated.

RESULTS

Data of 587 individuals were assessed. Among the 1 331 lesions detected at the initial colonoscopy, 1 151 (86.5%) were properly detected at the secondary colonoscopy. The proportions of correct detection at the secondary colonoscopy for ACN, non-advanced adenomas sized 5 to 9 mm, and non-advanced adenomas sized 1 to 4 mm were 100%, 95.4%, and 70.3%, respectively. In total, 175 adenomatous polyps and ACNs were newly detected at secondary colonoscopy in 112 individuals (19.1% of all individuals). Most of the lesions (165 lesions, 94.3%) were non-advanced adenomas, while advanced adenomas (5.7%) were also found.

CONCLUSION

Screening by observational colonoscopy followed by deferred polypectomy is a feasible option in terms of lesion detectability, particularly when lesions sized ≥ 5 mm are the treatment target.

NIR-II Fluorescence Endoscopy for Targeted Imaging of Colorectal Cancer

Endoscopy is a clinical gold standard to exam the interior of a hollow organ or body cavity. For the first of time, this study presents the design and construction of a fluorescent endoscopic system that harnesses the power of the second near-infrared window II (NIR-II) fluorescence imaging. An NIR-II fluorescent molecular probe, indocyanine green (ICG) conjugated bevacizumab (Bev-ICG) that targets vascular endothelial growth factor (VEGF), is successfully synthesized and evaluated along with the NIR-II endoscopy imaging system. Simultaneous NIR-II fluorescence and white-light (WL) imaging of VEGF is validated in an orthotopic rat colorectal cancer model. This NIR-II endoscopy system is a generalizable design, and it is compatible with the most of current clinic endoscopies. Similar hardware upgrades are expected to greatly promote the application of NIR-II fluorescent imaging in the clinic.

Comparative study of magnifying narrow-band imaging and conventional white light endoscopy in the diagnosis of Helicobacter pylori status after eradication therapy

Predicting Helicobacter pylori (Hp) status by endoscopic finding would be useful in recent clinical condition that the use of proton-pump inhibitors, anti-platelet, and anti-coagulant have become widespread. We aimed to elucidate the diagnostic accuracy of magnifying narrow-band imaging (M-NBI) endoscopy in distinguishing Hp status in patients with or without history of successful Hp eradication and compare this accuracy to the diagnostic accuracy of conventional white light (WL) endoscopy.Two hundred seven endoscopic examinations before and after Hp eradication were performed in prospective 163 patients. Endoscopic images by using the M-NBI and conventional WL were stored electronically and randomly allocated to 2 readers for evaluation. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were assessed by reference to Hp status assessed by conventional clinical test.Sensitivity, specificity, PPV, NPV, and accuracy for predicting Hp status for the conventional WL was 72.2%, 75.5%, 72.2%, 75.5%, and 73.9% for the first reader; 86.6%, 57.3%, 64.1%, 82.9%, and 71.0% for the second reader. On the other hand, sensitivity, specificity, PPV, NPV, and accuracy for predicting Hp status for the M-NBI was 96.9%, 93.6%, 93.1%, 97.1%, and 95.2% for the first reader; 92.8%, 93.6%, 92.8%, 93.6%, and 93.2% for the second reader, respectively. The diagnostic accuracy of M-NBI was significantly higher than that of WL (P < .0001 for both readers). Inter-observer agreement of M-NBI (k = 0.83) was also better than that of WL (k = 0.53).M-NBI was capable of distinguishing Hp status before and after eradication therapy.

Diagnostic value, safety, and histopathologic discrepancy risk factors for endoscopic forceps biopsy and transrectal ultrasound-guided core needle biopsy in rectum lesions

Background

Accurate preoperative pathologic diagnosis is very important for making appropriate therapeutic decisions for patients with rectal lesions. This study aimed (I) to determine diagnostic value and safety of endoscopic forceps biopsy (EFB) and transrectal ultrasound (TRUS)-guided core needle biopsy (CNB), and (II) to analyze the risk factors for their histopathologic discrepancies, with a particular focus in identifying the indicators for re-biopsy using TRUS-guided CNB after EFB.

Methods

We retrospectively reviewed the records of 102 patients who received EFB and TRUS-guided CNB before surgery. The histopathologic concordance and risk factors for underdiagnosis by EFB and TRUS-guided CNB were analyzed.

Results

Compared with postoperative pathology, the histopathologic discrepancy rate of EFB and TRUS-guided CNB was 51.0% (52/102 lesions) and 8.8% (9/102 lesions), respectively. The kappa value for consistency with postoperative pathology findings was 0.420 for EFB and 0.876 for TRUS-guided CNB. The multivariate analyses and receiver operating characteristic (ROC) curve indicated that lesions thickness ≥13.5 mm [OR 1.080 (95% CI: 1.021-1.142), P=0.007] and flat/depressed shape [OR 0.206 (95% CI: 0.076-0.564), P=0.002] were significantly associated with histopathologic discrepancies in EFB.

Conclusions

EFB was of limited clinical value in identifying the preoperative diagnosis of rectal lesions. Lesions thickness and flat/depressed shape at EFB were independent risk factors for pathologic discrepancies. TRUS-guided CNB may serve as a safe and effective supplement to routine EFB.

Prophylactic Snare Tip Soft Coagulation and Its Impact on Adenoma Recurrence After Colonic Endoscopic Mucosal Resection

BACKGROUND

Up to 20% of patients can have recurrence of adenomatous tissue at first surveillance study after colon endoscopic mucosal resection of large polyps.

AIMS

To determine whether an educational intervention discussing thermal ablation of lateral margins of the mucosectomy site of post-endoscopic mucosal resection defect with snare tip soft coagulation (STSC) would decrease adenoma recurrence.

METHODS

We performed a single-center quality improvement project from November 1, 2016, to November 30, 2017. Gastroenterologists underwent an educational intervention demonstrating the treatment of peripheral margins of mucosectomy site with STSC after standard mucosectomy technique. These cases (intervention group) were compared with consecutive procedures performed prior to commencement of the quality improvement study (pre-intervention group). Patients with large colorectal lesions (≥ 20 mm) were included.

RESULTS

Of the 120 patients here included, overall demographics of the groups were similar and the most common histology was sessile serrated adenoma (study group 45% vs 32% control group). Adenoma recurrence on intervention group and pre-intervention group was 12% versus 30%; p = 0.01. On univariate analysis, biopsy prior to mucosectomy, intraprocedural bleeding, and application of STSC on mucosectomy defect were the strongest predictors of adenoma recurrence. Adenoma recurrence in the intervention group was significantly lower than in the pre-intervention group in both univariate (odds ratio, 0.3 [95% CI, 0.11-0.80]) and multivariate analyses (odds ratio, 0.2 [95% CI, 0.12-0.92]).

CONCLUSIONS

The implementation of STSC of post-endoscopic mucosal resection peripheral defects is clinically feasible and significantly decreased adenoma recurrence.

Estimation of invasion depth of early colorectal cancer using EUS and NBI-ME: a meta-analysis

BACKGROUND

Endoscopic ultrasonography (EUS) and narrow band imaging-magnifying endoscopy (NBI-ME) are often used as diagnostic tools to estimate the depth of invasion in early colorectal cancer (CRC). The aim of this study was to compare NBI-ME with EUS in distinguishing between slight submucosal invasion (invasion depth < 1000 μm) and massive submucosal invasion in patients with early CRC, since slight submucosal invasion is currently considered as an indication for endoscopic resection.

METHODS

For this meta-analysis, relevant studies were identified from PubMed, Embase, Web of Science, Scopus and the Cochrane Library databases between January 1997 and September 2016. Data on the yield of tumors were extracted, pooled, and analyzed by stata12.0 software. The sensitivity, specificity, positive likelihood ratio and negative likelihood ratio in differentiating slight submucosal invasion from massive submucosal invasion were calculated for both diagnostic modalities.

RESULTS

Sixteen studies involving 2197 lesions were included: nine were studies on EUS and 7 were studies on NBI-ME. The pooled sensitivity of EUS was 0.902 (95% CI 0.863-0.930), the specificity was 0.877 (95% CI 0.810-0.922), the positive likelihood ratio was 7.314 (95% CI 4.551-11.755) and the negative likelihood ratio was 0.112 (95% CI 0.076-0.164). The pooled sensitivity and specificity of NBI-ME were 0.981 (95% CI 0.949-0.993) and 0.651 (95% CI 0.600-0.699), respectively, the positive likelihood ratio was 2.815 (95% CI 2.432-3.258) and the negative likelihood ratio was 0.029 (95% CI 0.010-0.080).

CONCLUSIONS

The sensitivity tended to be higher in ME-NBI than EUS for early CRC with slight submucosal invasion, whereas the specificity was significantly lower in NBI-ME than in EUS.

Comparison of optical coherence tomography angiography and narrow-band imaging using a bimodal endoscope

We present coregistered images of tissue vasculature that allow a direct comparison between the performance of narrow-band imaging (NBI) and optical coherence tomography angiography (OCTA). Images were generated with a bimodal endomicroscope having a size of 15  ×  2.4  ×  3.3  ³   ( l  ,  w  ,  h  )   that combines two imaging channels. The white light imaging channel was used to perform NBI, the current gold standard for endoscopic visualization of vessels. The second channel allowed the simultaneous acquisition of optical coherence tomography (OCT) and OCTA images, enabling a three-dimensional (3-D) visualization of morphological as well as functional tissue information. In order to obtain 3-D OCT images scanning of the light-transmitting fiber was implemented by a small piezoelectric tube. A field of view of ∼1.1  mm was achieved for both modalities. Under the assumption that OCTA can address current limitations of NBI, their performance was studied and compared during in vivo experiments. The preliminary results show the potential of OCT regarding an improved visualization and localization of vessel beds, which can be beneficial for diagnosis of pathological conditions.

Randomized, back-to-back trial of a new generation NBI with a high-definition white light (HQ290) for detecting colorectal polyps

Background: The benefits of narrow band imaging (NBI) for improving the detection rate of colorectal polyps remain unclear. New generation NBI using the 290 system (290-NBI) provides an at least two-fold brighter image than that of the previous version. We aimed to compare polyp miss rates between 290-NBI colonoscopy and high-definition white light endoscopy (HDWL). Methods: In total, 117 patients were randomized to undergo either 290-NBI or HDWL from June 2015 to February 2017. In the HDWL group, we performed HDWL as an initial inspection, followed by a second inspection with NBI. In the 290-NBI group, NBI was performed as the initial inspection, followed by a second inspection with HDWL. We compared polyp and adenoma detection rates and polyp miss rates (PMR) between the two groups and analyzed the factors associated with the PMR. Results: In total, 127 polyps were detected in the 117 patients. No differences in adenoma or polyp detection rates were observed between the two groups. The PMR for 290-NBI was 20.6% and that for HDWL was 33.9% (p = .068). However, the non-adenomatous PMR for 290-NBI was significantly lower than that of HDWL (11.5% vs. 52.2%, p = .002). Furthermore, the miss rates of polyps on the left side of the colon, flat-type polyps, and non-adenomatous polyps were significantly lower in the 290-NBI than HDWL. Conclusions: New generation NBI may reduce PMR, especially of flat-type and non-adenomatous polyps and those on the left side of the colon. (UMIN000025505).

Optical Technologies for Endoscopic Real-Time Histologic Assessment of Colorectal Polyps: A Meta-Analysis

OBJECTIVES

Accurate, real-time, endoscopic risk stratification of colorectal polyps would improve decision-making and optimize clinical efficiency. Technologies to manipulate endoscopic optical outputs can be used to predict polyp histology in vivo; however, it remains unclear how accuracy has progressed and whether it is sufficient for routine clinical implementation.

METHODS

A meta-analysis was conducted by searching MEDLINE, Embase, and the Cochrane Library. Studies were included if they prospectively deployed an endoscopic optical technology for real-time in vivo prediction of adenomatous colorectal polyps. Polyposis and inflammatory bowel diseases were excluded. Bayesian bivariate meta-analysis was performed, presenting 95% confidence intervals (CI).

RESULTS

One hundred two studies using optical technologies on 33,123 colorectal polyps were included. Digital chromoendoscopy differentiated neoplasia (adenoma and adenocarcinoma) from benign polyps with sensitivity of 92.2% (90.6%-93.9% CI) and specificity of 84.0% (81.5%-86.3% CI), with no difference between constituent technologies (narrow-band imaging, Fuji intelligent Chromo Endoscopy, iSCAN) or with only diminutive polyps. Dye chromoendoscopy had sensitivity of 92.7% (90.1%-94.9% CI) and specificity of 86.6% (82.9%-89.9% CI), similarly unchanged for diminutive polyps. Spectral analysis of autofluorescence had sensitivity of 94.4% (84.0%-99.1% CI) and specificity of 50.9% (13.2%-88.8% CI). Endomicroscopy had sensitivity of 93.6% (85.3%-98.3% CI) and specificity of 92.5% (81.8%-98.1% CI). Computer-aided diagnosis had sensitivity of 88.9% (74.2%-96.7% CI) and specificity of 80.4% (52.6%-95.7% CI). Prediction confidence and endoscopist experience alone did not significantly improve any technology. The only subgroup to demonstrate a negative predictive value for adenoma above 90% was digital chromoendoscopy, making high confidence predictions of diminutive recto-sigmoid polyps. Chronologic meta-analyses show a falling negative predictive value over time. A significant publication bias exists.

DISCUSSION

This novel approach to meta-analysis demonstrates that existing optical technologies are increasingly unlikely to allow safe "resect and discard" strategies and that step-change innovation may be required. A "diagnose and leave" strategy may be supported for diminutive recto-sigmoid polyps diagnosed with high confidence; however, limitations exist in the evidence base for this cohort.

A study on confocal endomicroscopy in comparison with histopathology for polypoidal lesions of the gastrointestinal tract: A prospective single-centre experience

BACKGROUND

Confocal laser endomicroscopy (CLE) has a potential to make optical diagnosis of neoplastic polypoidal lesions and may replace traditional histology in the proposed "diagnose and discard approach". The present study was planned to assess the accuracy of probe-based CLE in predicting histology of polypoidal lesions of gastrointestinal (GI) tract in vivo before their removal.

METHODS

In this prospective single-centre study, patients with upper and/or lower GI polypoidal lesions were enrolled. After detection of polypoidal lesions with white light endoscopy, probe-based CLE examination was performed. Real-time and offline presumptive CLE diagnosis of polypoidal lesions was made as per Miami classification and was compared with histopathology as the gold standard.

RESULTS

A total of 50 GI polyps from 50 patients (28 males) were assessed. The mean (±SD) size of polyps was 13.7 (± 8.5) mm. Most polyps were located at the cecum (24.0%) or stomach (24.0%). On histological examination, hyperplastic and adenomatous polyps, adenocarcinoma, and lipoma were seen in 54%, 26%, 18% and 2% patients, respectively. On comparison of real-time CLE examination with histopathology, 40 (83.3%) and 8 patients (16.7%) had concordant and discordant results, respectively. Two polyps were inconclusively diagnosed on CLE. On offline examination, concordance with histopathology was observed in 85.4% (n = 41) of polyps, which was marginally better than online examination, though the difference was not statistically significant (p = 0.45). On comparing the real-time and offline findings of CLE, concordance was found in 91.7% of the cases. Accuracy, sensitivity, specificity, positive and negative predictive values on real-time evaluation were 83.3%, 87.5%, 79.1%, 80.7%, and 86.3%, respectively.

CONCLUSION

CLE is a useful tool for prediction of histology to assess the polypoidal lesions of the GI tract, and it may avoid polypectomy at least in some patients.

Clinical diagnostic value of digestive endoscopic narrow-band imaging in early esophageal cancer

Clinical diagnostic value of digestive endoscopic narrow-band imaging in early esophageal cancer (EC) and benign lesions was explored. Retrospective analysis was carried out on the clinical data of 186 patients with early EC and benign lesions diagnosed by the Department of Gastroenterology in Cangzhou Central Hospital from February 2011 to April 2018. Among them, 102 patients examined by Narrow Band Imaging (NBI) were regarded as the research group. Eighty-four patients examined by conventional white light staining endoscopy were regarded as the control group. The lesion boundary definition, image clarity, sensitivity, specificity, positive predictive value, negative predictive value, diagnostic compliance rate, detection rate of lesions and adverse reactions were compared between the groups after examination. The results showed that the lesion boundary definition in the research group was higher than that in the control group (P<0.05). The 4-points of image clarity in the research group was higher than that in the control group (P<0.05). The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic compliance rate of the early EC and benign lesions in the research group were higher than those in the control group (P<0.05). The detection rate of the upper, middle and lower segments of lesions in the research group was higher than that in the control group. In conclusion, NBI has higher sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic compliance rate for the diagnosis of early EC and benign lesions. Also it has more accuracy in the detection of lesions and fewer adverse reactions, the screening of early EC and benign lesions is effective, and worth promoting clinically.

Incidence of Advanced Colorectal Neoplasia in Individuals With Untreated Diminutive Colorectal Adenomas Diagnosed by Magnifying Image-Enhanced Endoscopy

OBJECTIVES

Because of the increasing number of detected diminutive colorectal adenomas, the "diagnose-and-do-not-resect" approach has recently attracted attention as an alternative to resection. We evaluated the cumulative incidence of advanced colorectal neoplasia (ACN) in individuals with untreated diminutive adenomas and compared this incidence in individuals without adenomas.

METHODS

Data from 1,378 individuals who underwent first screening colonoscopy (CS) and at least one follow-up CS without polypectomy were analyzed. Patients with no adenomas or with only nonadvanced diminutive adenomas (<5 mm) diagnosed by magnifying image-enhanced endoscopy were scheduled to undergo a follow-up CS within 5 years after the initial CS without treatment. The participants were divided into 2 groups: those with untreated diminutive adenomas (group A) and those with no adenomas (group B). The cumulative incidence of ACN and the hazard ratio were assessed using Gray's test and the Fine and Gray model.

RESULTS

During the median follow-up period of 60.9 months, 21 ACNs were detected. The 5-year cumulative incidences of ACN in group A (n = 361) and group B (n = 1,017) were 1.4% (95% confidence interval [CI]: 0.5-3.4) and 0.8% (95% CI: 0.3-1.7), respectively, without a statistically significant difference (P = 0.23). No ACNs developed from unresected adenomas. The smoking status was significantly associated with the incidence of ACN, and the hazard ratio for ACN in group A vs group B adjusted for smoking status was 1.43 (95% CI: 0.52-3.90; P = 0.48).

DISCUSSION

The low 5-year cumulative incidence of ACN suggests the potential to adopt the "diagnose-and-do-not-resect" strategy as an alternative option for diminutive adenomas not requiring excessive surveillance.

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

Background

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

Methods

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

Results

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

Conclusion

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

Electronic supplementary material

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

Standards of diagnostic colonoscopy for early-stage neoplasia: Recommendations by an Asian private group

BACKGROUND AND AIM

In recent years, the incidence of colorectal cancer has been increasing, and it is now becoming the major cause of cancer death in Asian countries. The aim of the present study was to develop Asian expert-based consensus to standardize the preparation, detection and characterization for the diagnosis of early-stage colorectal neoplasia.

METHODS

A professional group was formed by 36 experts of the Asian Novel Bio-Imaging and Intervention Group (ANBI2 G) members. Representatives from 12 Asia-Pacific countries participated in the meeting. The group organized three consensus meetings focusing on diagnostic endoscopy for gastrointestinal neoplasia. The Delphi method was used to develop the consensus statements.

RESULTS

Through the three consensus meetings with debating, reviewing the literature and regional data, a consensus was reached at third meeting in 2016. The consensus was reached on a total of 10 statements. Summary of statements is as follows: (i) Adequate bowel preparation for high-quality colonoscopy; (ii) Antispasmodic agents for lesion detection; (iii) Image-enhanced endoscopy (IEE) for polyp detection; (iv) Adenoma detection rate for quality indicators; (v) Good documentation of colonoscopy findings; (vi) Complication rates; (vii) Cecal intubation rate; (viii) Cap-assisted colonoscopy (CAC) for polyp detection; (ix) Macroscopic classification using indigocarmine spray for characterization of colorectal lesions; and (x) IEE and/or magnifying endoscopy for prediction of histology.

CONCLUSION

This consensus provides guidance for carrying out endoscopic diagnosis and characterization for early-stage colorectal neoplasia based on the evidence. This will enhance the quality of endoscopic diagnosis and improve detection of early-stage colorectal neoplasia.

Diagnostic yield of the Japan NBI Expert Team (JNET) classification for endoscopic diagnosis of superficial colorectal neoplasms in a large-scale clinical practice database

Background

Magnifying Narrow Band Imaging (NBI) during colonoscopy is a reliable method for differential and depth diagnoses of colorectal lesions. This study examined the diagnostic yield of magnifying NBI based on the Japan NBI Expert Team (JNET) classification in a clinical setting using a large-scale clinical practice database. Types 1, 2A, 2B and 3 correspond to the histopathological classifications of hyperplastic polyp/sessile-serrated polyp, low-grade intramucosal neoplasia, high-grade intramucosal neoplasia/shallow submucosal invasive cancer, and deep submucosal invasive cancer, respectively.

Methods

The prospective records of colonoscopy reports and pathological data of 1558 consecutive superficial colorectal lesions removed by colonoscopy were retrospectively analysed. After excluding 156 lesions, the documented JNET classifications of the remaining 1402 colorectal lesions were analysed. Diagnostic yield was analysed and also compared between expert endoscopists and nonexpert endoscopists.

Results

The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were respectively 75%, 96%, 74%, 96% and 93% for type 1; 91%, 70%, 92%, 67% and 87% for type 2A; 42%, 95%, 26%, 98% and 93% for type 2B; and 35%, 100%, 93%, 98% and 98% for type 3. Nonexpert and expert endoscopists alike had specificity, NPV and accuracy >90% for types 1, 2B and 3, and a sensitivity and PPV >90% for type 2A. Type 2B had a low sensitivity of 42% because it included various histological features.

Conclusions

The JNET classification proved useful in a clinical setting both for expert and nonexpert endoscopists, as was expected from the original JNET definition, but type 2B requires further investigation using pit pattern diagnosis.

Endoscopic features of sessile serrated adenoma/polyps under narrowband imaging: A retrospective study

OBJECTIVE

Sessile serrated adenoma/polyps (SSA/P) are recognized as precancerous lesions in the colon and resemble hyperplastic polyps (HP). Definite endoscopic features under narrow band imaging (NBI) with or without magnification may help differentiate these two lesions. Our study aimed to identify specific endoscopic features of SSA/P by NBI.

METHODS

A total of 199 patients with histopathologically proven colorectal SSA/P or HP after a polypectomy were enrolled. Magnifying and non-magnifying NBI pictures of 206 matching lesions were evaluated by one expert and two non-expert endoscopists using various endoscopic characteristics retrospectively.

RESULTS

Multivariate analysis indicated that a clouded surface (odds ratio [OR] 6.48, 95% confidence interval [CI] 2.72-15.44, P = 0.000) and dilated and branching vessels (DBV) (OR 7.95, 95% CI 3.71-17.02, P = 0.000) were significant endoscopic features for diagnosing SSA/P compared with HP. The combination of these two features could improve diagnostic specificity to 96%, and the area under the receiver operating characteristic curve was 0.749. However, it seemed that the presence of dark spots (OR 1.93, 95% CI 0.94-4.00, P = 0.075) was not a definite feature in differentiating these two lesions. Neither a mucus cap nor CP-II meshed capillary vessels showed statistical significance in differentiating SSA/P from HP (P = 0.590 and 0.293, respectively).

CONCLUSIONS

A clouded surface and DBV were two indicators for diagnosing SSA/P. Combining these two factors together under NBI with or without magnification achieved better diagnostic performance than when they were used alone.

An adaptive-coherence light source for hyperspectral, topographic, and flow-contrast imaging

Colorectal cancer accounts for an estimated 8% of cancer deaths in the United States with a five-year survival rate of 55-75%. The early detection and removal of precancerous lesions is critical for reducing mortality, but subtle neoplastic growths, such as non-polypoid lesions, often go undetected during routine colonoscopy. Current approaches to flat or depressed lesion detection are ineffective due to the poor contrast of subtle features in white light endoscopy. Towards improving colorectal lesion contrast, we present an endoscopic light source with custom laser channels for multimodal color, topographic, and speckle contrast flow imaging. Three red-green-blue laser units, paired with laser speckle reducers, are coupled into endoscopic fiber optic light guides in a benchtop endoscope. Tissue phantom topography is reconstructed using alternating illumination of the laser units and a photometric stereo endoscopy algorithm. The contrast of flow regions is enhanced in an optical flow phantom using laser speckle contrast imaging. Further, the system retains the ability to offer white light and narrow band illumination modes with improved power efficiency, a reduced size, and longer lifetimes compared to conventional endoscopic arc lamp sources. This novel endoscopic light source design shows promise for increasing the detection of subtle lesions in routine colonoscopy screening.

Should We Resect and Discard Low Risk Diminutive Colon Polyps

Diminutive colorectal polyps <5 mm are very common and almost universally benign. The current strategy of resection with histological confirmation of all colorectal polyps is costly and may increase the risk of colonoscopy. Accurate, optical diagnosis without histology can be achieved with currently available endoscopic technologies. The American Society of Gastrointestinal Endoscopy Preservation and Incorporation of Valuable endoscopic Innovations supports strategies for optical diagnosis of small non neoplastic polyps as long as two criteria are met. For hyperplastic appearing polyps <5 mm in recto-sigmoid colon, the negative predictive value should be at least 90%. For diminutive low grade adenomatous appearing polyps, a resect and discard strategy should be sufficiently accurate such that post-polypectomy surveillance recommendations based on the optical diagnosis, agree with a histologically diagnosis at least 90% of the time. Although the resect and discard as well as diagnose and leave behind approach has major benefits with regard to both safety and cost, it has yet to be used widely in practice. To fully implement such as strategy, there is a need for better-quality training, quality assurance, and patient acceptance. In the article, we will review the current state of the science on optical diagnose of colorectal polyps and its implications for colonoscopy practice.

Narrow band imaging and white light endoscopy in the characterization of a polypectomy scar: A single-blind observational study

AIM

To assess the incremental benefit of narrow band imaging (NBI) and white light endoscopy (WLE), randomizing the initial technique for the detection of residual neoplasia at the polypectomy scar after an endoscopic piecemeal mucosal resection (EPMR).

METHODS

We conducted an observational study in an academic center to assess the incremental benefit of NBI and WLE randomly applied 1:1 (NBI-WLE or WLE-NBI) in the follow-up of a post-EPMR scar by the same endoscopist.

RESULTS

A total of 112 EPMR scars were included. The median baseline polyp size was 20 mm (interquartile range: 14-30). At first review, NBI and WLE showed good sensitivity (85.0% vs 78.9%), specificity (77.1% vs 84.2%) and overall accuracy (80.0% vs 82.5%). NBI after WLE (WLE-NBI group) improved accuracy, but this difference was not statistically significant [area under the curve (AUC): 86.8% vs 81.6%, P = 0.15]. WLE after NBI (NBI-WLE group) did not improve accuracy (AUC: 81.4% vs 81.1%, P = 0.9). Overall, recurrence was found in 39/112 (34.8%) lesions.

CONCLUSION

Although no statistically significant differences were found between the two techniques at the first post-EPMR assessment, the use of NBI after WLE may improve residual neoplasia detection. Nevertheless, biopsy is still required in the first scar review.

Clinical outcomes of the "resect and discard" strategy using magnifying narrow-band imaging for small (< 10 mm) colorectal polyps

Background and study aim  The "resect and discard" strategy is a new paradigm for the management of small colorectal polyps that reduces the cost and effort related to pathological diagnosis after polypectomy. This retrospective study aimed to clarify the clinical outcome of the "resect and discard" strategy for small colorectal polyps. Patients and methods  The clinical records were reviewed from 501 consecutive patients who underwent the "resect and discard" strategy for colorectal polyps smaller than 10 mm at our hospital between January 2008 and December 2010. All colorectal lesions were evaluated onsite under magnifying narrow-band imaging after careful conventional white-light imaging. In cases of low grade adenoma predicted with high confidence, colonoscopists selected the "resect and discard" option without formal histopathology. The mid-term outcomes were evaluated to validate the curability of the "resect and discard" strategy. Results  The present study included 501 consecutive patients with 816 lesions. The mid-term outcomes were examined for 476 (95 %) patients who received follow-up for at least 1 year after undergoing the "resect and discard" strategy. The median observation period was 83 months (range 12 - 117 months). No patient died from colorectal cancer related to the procedure, resulting in a disease-specific survival rate of 100 %. There were no local and/or distant recurrences detected during follow-up. Conclusions  The "resect and discard" strategy for small colorectal polyps under strict preoperative diagnosis achieves excellent mid-term outcome.

Narrow band imaging and serology in the assessment of premalignant gastric pathology

BACKGROUND

Patient outcomes in gastric adenocarcinoma are poor due to late diagnosis. Detecting and treating at the premalignant stage has the potential to improve this. Helicobacter pylori is also a strong risk factor for this disease.

AIMS

Primary aims were to assess the diagnostic accuracy of magnified narrow band imaging (NBI-Z) endoscopy and serology in detecting normal mucosa, H. pylori gastritis and gastric atrophy. Secondary aims were to compare the diagnostic accuracies of two classification systems using both NBI-Z and white light endoscopy with magnification (WLE-Z) and evaluate the inter-observer agreement.

METHODS

Patients were prospectively recruited. Images of gastric mucosa were stored with histology and serum for IgG H. pylori and Pepsinogen (PG) I/II ELISAs. Blinded expert endoscopists agreed on mucosal pattern. Mucosal images and serological markers were compared with histology. Kappa statistics determined inter-observer variability for randomly allocated images among four experts and four non-experts.

RESULTS

116 patients were prospectively recruited. Diagnostic accuracy of NBI-Z for determining normal gastric mucosa was 0.87(95%CI 0.82-0.92), H. pylori gastritis 0.65(95%CI 0.55-0.75) and gastric atrophy 0.88(95%CI 0.81-0.94). NBI-Z was superior to serology at detecting gastric atrophy: NBI-Z gastric atrophy 0.88(95%CI 0.81-0.94) vs PGI/II ratio < 3 0.74(95%CI 0.62-0.85) p<.0001. Overall NBI-Z was superior to WLE-Z in detecting disease using two validated classifications. Inter-observer agreement was 0.63(95%CI 0.51-0.73).

CONCLUSIONS

NBI-Z accurately detects changes in the GI mucosa which currently depend on histology. NBI-Z is useful in the detection of precancerous conditions, potentially improving patient outcomes with early intervention to prevent gastric cancer.

Clinical Significance of Diminutive Colonic Polyps in Elderly Patients

Background and Objectives:

Colorectal cancer is the third leading cause of cancer-related death. Excision of premalignant polyps has a significant impact on reducing colorectal cancer mortality and morbidity. Colonoscopy is considered to be the gold standard for the diagnosis and affords an opportunity for treatment of colonic polyps. In recent years, serious debates have taken place because of the biological characteristics of diminutive polyps (DPs), polypectomy complications, and serious costs. There has not yet been a consensus on the management of DPs. The objectives of this study were to demonstrate the real clinical importance of DPs smaller than 5 mm in diameter, which are frequently seen in geriatric patients by new endoscopic techniques, and to help in determining screening and surveillance programs.

Methods:

The patients who underwent colonoscopy and were found to have a diminutive colorectal polyp (<5 mm from September 1, 2016 through September 1, 2017), were classified into 3 groups according to the imaging method used: flexible spectral imaging color enhancement (FICE), narrow band imaging (NBI), or I-SCAN. In all groups, demographic data were compared according to Paris classification (morphologic) and Kudo classification (correlation between the prediction of endoscopic diagnosis and final pathological examination) in terms of sensitivity, specificity, and negative and positive predictive values.

Results:

Two hundred sixty-seven patients were included in the study: 97 in the NBI group, 83 in the FICE group, and 87 in the I-SCAN group. There were no statistically significant differences between NBI, FICE, and I-SCAN in differentiating neoplastic and nonneoplastic polyps, according to the Kruskal-Wallis test (P = .809).

Conclusions:

The estimated progression rates of DPs to advanced adenomas or colorectal cancer (CRC) are very low. Missing these polyps or not excising them may lead to failure to diagnose some cancers. There is a need for further comprehensive studies of removing all polyps to determine whether non–high-risk lesions require further pathologic examination and to re-examine routine surveillance programs.

Optical Diagnosis for Colorectal Polyps: A Useful Technique Now or in the Future?

In the last few years, interest in the optical diagnosis of colorectal polyps has increased among gastroenterologists. Several studies have shown that the optical diagnosis of small colorectal polyps is safe and feasible in routine clinical practice and is comparable to histopathology. The Narrow-band Imaging International Colorectal Endoscopic Classification provides a validated criterion for the classification of neoplastic and nonneoplastic polyps as well as polyps with deep submucosal invasion using narrow band imaging during real-time colonoscopy. The aim of the present review is to assess the current evidence for and limitations of optical diagnosis and to propose a systematic approach for transferring research findings to patient care.

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

INTRODUCTION

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Evaluation of New Technologies in Gastrointestinal Endoscopy

Gastrointestinal (GI) tumors are the most commonly diagnosed cancers worldwide and the second leading cause of cancer-related death. Endoscopy is the gold standard for diagnosis of GI cancers. Early diagnosis of GI tumors by endoscopy at the precancerous or early stage may decrease the prevalence and mortality rate of GI cancers. The preventive role of endoscopic interventions and the limitations of conventional white-light endoscopy have given rise to myriad innovations. Chromoendoscopy with dye injection can be used to detect lesions at an early stage. However, the prolonged procedure duration and steep learning curve are disadvantages of chromoendoscopy. Recent technological advances in imaging enhancement have enabled detection of GI lesions without the need for dye injection, using digital chromoendoscopy systems, of which flexible spectral-imaging color enhancement, narrow-band imaging, and I-Scan are the most frequently used. The combination of endoscopic image magnification and high-definition optical systems using digital endoscopic methods has increased the diagnostic value of endoscopy. The development of confocal laser endomicroscopy has also improved in vivo endoscopic diagnosis. This review focuses on the latest technological innovations in endoscopy.

Magnifying Blue Laser Imaging versus Magnifying Narrow-Band Imaging for the Diagnosis of Early Gastric Cancer: A Prospective, Multicenter, Comparative Study

BACKGROUND/AIMS

The diagnostic efficacy of magnifying blue laser imaging (M-BLI) and M-BLI in bright mode (M-BLI-bright) in the identification of early gastric cancer (EGC) was evaluated for comparison to that of magnifying narrow-band imaging (M-NBI).

METHODS

This prospective, multicenter study evaluated 114 gastric lesions examined using M-BLI, M-BLI-bright, and M-NBI between May 2012 and November 2012; 104 EGCs were evaluated by each modality. The vessel plus surface classification system was used to evaluate the demarcation line (DL), microvascular pattern (MVP), and microsurface pattern (MSP).

RESULTS

M-BLI, M-BLI-bright, and M-NBI revealed a DL for 96.1, 98.1, and 98.1% and irregular MVP for 95.1, 95.1, and 96.2% of lesions, respectively, with no significant difference. Irregular MSP was observed by M-BLI, M-BLI-bright, and M-NBI in 97.1, 90.4, and 78.8% of lesions, respectively, with significant differences (p < 0.001). The proportion of moderately differentiated adenocarcinoma with irregular MSP on M-BLI and absent MSP on M-NBI was significantly higher than that with irregular MSP on M-BLI and M-NBI (35.0 and 9.9%, respectively; p = 0.002).

CONCLUSION

M-BLI and M-BLI-bright provided excellent visualization of microstructures and microvessels similar to M-NBI. Irregular MSP in a moderately differentiated adenocarcinoma might be frequently visualized using M-BLI and M-BLI-bright compared with using M-NBI.

Comparison of the diagnostic performance between magnifying chromoendoscopy and magnifying narrow-band imaging for superficial colorectal neoplasms: an online survey

BACKGROUND AND AIMS

Magnifying narrow-band imaging (mag-NBI) and magnifying chromoendoscopy using crystal violet staining for pit pattern analysis (pit pattern) is highly accurate for diagnosing invasion depth of superficial colorectal neoplasms. However, NBI and pit pattern have not been compared.

METHODS

We conducted an online survey of endoscopists interested in image-enhanced endoscopy. Still images using white light, mag-NBI, and pit pattern were collected from lesions diagnosed at the National Cancer Center Hospital (NCCH), Tokyo, Japan. Sixty endoscopists from outside NCCH who typically use magnifying endoscopy were recruited for this survey. We assessed the diagnostic accuracy using receiver operating characteristic (ROC) analysis based on a calculation of the area under the ROC curve.

RESULTS

One hundred early colorectal neoplasms were selected for this survey. Histopathology revealed that, although 67 of the lesions had high-grade dysplasia or carcinoma with superficial submucosal (SM-s) invasion, the other 33 lesions had a carcinoma with deep submucosal invasion (SM-d). Comparing the area under the ROC curve from mag-NBI with that of pit pattern, the latter showed significantly higher diagnostic accuracy for depth invasion (0.83 [95% CI, 0.81-0.85] for mag-NBI, 0.88 [95% CI, 0.85-0.89] for pit pattern, P = .013).

CONCLUSIONS

Pit pattern should be the first choice for diagnosing invasion depth as the most reliable modality rather than mag-NBI.

Prospective Comparative Study of Laparoscopic Narrow Band Imaging (NBI) Versus Standard Imaging in Gynecologic Oncology

BACKGROUND

Narrow band imaging (NBI) is an optic filtration enhancement for endoscopy that uses two wavelengths of light (415 and 540 nm) to highlight superficial microvascular patterns. It has been successfully utilized to improve identification of lesions with abnormal vasculature, which is associated with endometriosis and endometrial cancer. Case studies suggest it may also facilitate surgical staging of gynecologic cancer, which is critical in determining appropriate adjuvant therapies. A technology that enhances the ability to identify metastatic disease during minimally invasive surgery (MIS) could make an important difference in patient outcomes.

METHODS

A prospective comparative study was conducted to evaluate patients with clinical indication for diagnostic or operative laparoscopy. All received white light imaging followed by NBI during the same procedure. Suspicious lesions were examined and photographed, using both modalities, before excision. The two techniques were compared. Positive predictive value, negative predictive value, and diagnostic accuracy in identifying histologically confirmed metastatic lesions were assessed, using appropriate statistical methods.

RESULTS

Of 124 patients enrolled in the study, 94 were evaluable; 30 did not undergo MIS and were therefore excluded. A significantly higher number of peritoneal abnormalities were identified with NBI versus white light imaging (P = 0.0239). However, no statistically significant difference (P = 0.18, patient level) was observed in identification of histologically confirmed metastatic disease.

CONCLUSIONS

NBI imaging provides a unique contrast between peritoneal surface and microvascular patterns. However, the results of this study suggest that NBI-enhanced laparoscopy does not provide superior detection of peritoneal surface malignancy compared with standard white light high-definition laparoscopy.

Optical Design with Narrow-Band Imaging for a Capsule Endoscope

The study proposes narrow-band imaging (NBI) lens design of 415 nm and 540 nm of a capsule endoscope (CE). The researches show that in terms of the rate of accuracy in detecting and screening neoplastic and nonneoplastic intestinal lesions, the NBI system outperformed that of traditional endoscopes and rivaled that of chromoendoscopes. In the proposed NBI CE optical system, the simulation result shows the field of view (FOV) was 109.8°; the modulation transfer function (MTF) could achieve 12.5% at 285 lp/mm and 34.1% at 144 lp/mm. The relative illumination reaches more than 60%, and the system total length was less than 4 mm. Finally, this design provides high-quality images for a 300-megapixel 1/4^″ CMOS image sensor with a pixel size of 1.75 μm.

Application of image-enhanced endoscopy in diagnosis of colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies, and in China the incidence and mortality of CRC are among the top in the world. Early diagnosis of CRC can improve the prognosis significantly. Image enhancement techniques have already been applied to endoscopy, including narrow band imaging, flexible spectral imaging, i-Scan, and blue laser imaging endoscopy system. These techniques, combined with image pre-processing or post-processing method, might improve the detection of lesions by enhancing the color contrast between lesions and their surrounding mucosa. Nowadays, several classification systems for colorectal tumors have been established based on the surface pattern and microvascular morphology of lesions. Image enhancement technology might display the microvascular structures more clearly and determine the malignancy and infiltrating depth of lesions more accurately.

Photoacoustic and hyperspectral dual-modality endoscope

We have developed a dual-modality endoscope composed of photoacoustic (PA) and hyperspectral imaging, capable of visualizing both structural and functional properties of bio-tissue. The endoscope's composition and scanning mechanism was described, and the feasibility of the dual-modality endoscope was verified by mimic phantom experiments. Lately, we demonstrated its endoscopic workability through in vivo experiments. The experimental results showed that the proposed herein hybrid endoscope can provide optical imaging of the surface and tomography imaging for the deeper features, and a functional oxygen saturation rate map of the same imaging area. We demonstrated optical-resolution PA imaging of vascular structures and an oxygen saturation rate map in a rabbit's rectum. It confirmed that this dual-modality endoscope can play an important role in comprehensive clinical applications.

Applications of acetic acid spray combined with narrow band imaging in diagnosis of early gastrointestinal cancers and precancerous lesions

Many new endoscopic techniques have been used for the diagnosis of early gastrointestinal cancers and precancerous lesions, such as magnifying endoscopy, narrow-band imaging (NBI), Fuji intelligent chromoendiscopy, i-scan imaging, confocal laser endomicroscopy, and chromoendoscopy (Lugol's iodine, indigo carmine, methylene blue, acetic acid, and crystal violet). Each technique has its own advantages and disadvantages (e.g., being expensive and prolonged examination duration). Spraying acetic acid onto the mucosal surface can enhance the recognition of mucosal surface architecture, and NBI has the advantage to display the microvascular morphology. Thus, acetic acid spray combined with NBI endoscopy can greatly improve the diagnosis of early gastrointestinal cancers and precancerous lesions. Since this combination has low cost and no adverse reactions, they can be used in primary hospitals without magnification endoscopy.

Comparison of linked color imaging and white-light colonoscopy for detection of colorectal polyps: a multicenter, randomized, crossover trial

BACKGROUND AND AIMS

Linked color imaging (LCI), a recently developed technology, uses a laser endoscopic system to enhance the color separation of red color to depict red and white colors more vividly. The benefits of LCI in the detection of colorectal polyps remain unknown. The aim of this study was to assess the ability of LCI to improve the detection of colorectal polyps compared with white-light (WL) endoscopy.

METHODS

We performed a multicenter, crossover, prospective, randomized controlled trial in 3 hospitals in China. All patients underwent crossover colonoscopies with LCI and WL endoscopy in a randomized order. All lesions were removed during the second endoscopic procedure. The primary outcome measure was the difference in sensitivity between LCI and WL endoscopy for the detection of colorectal polyps. The secondary outcome measures were the adenoma detection rate per patient in the 2 groups and the factors associated with polyp miss rates.

RESULTS

A total of 152 patients were randomized, and 141 were included in the analysis. The overall polyp detection rate increased significantly by 24% for LCI colonoscopy, corresponding to a higher sensitivity with LCI than with WL endoscopy (91% vs 73%, P < .0001). Furthermore, LCI identified significantly more patients (32%) with polyps. The per-patient adenoma detection rate was significantly higher for LCI than for WL endoscopy (37% vs 28%; 95% confidence interval, 2.39%-19.41%).

CONCLUSIONS

LCI improves the detection of colorectal polyps and adenomas during colonoscopy. (Clinical trial registration number: NCT02724397.).

Magnifying NBI Patterns of Gastric Mucosa After Helicobacter pylori Eradication and Its Potential Link to the Gastric Cancer Risk

BACKGROUND

Gastric cancer develops after successful H. pylori eradication in patients with severe atrophic gastritis. We classified atrophic and non-atrophic mucosa of gastric body using magnifying NBI endoscopy in patients after successful H. pylori eradication.

MATERIALS AND METHODS

One hundred and twenty-five patients after successful H. pylori eradication (median period after eradication: 36 months) were enrolled. Magnifying NBI patterns in the uninvolved gastric body were divided into the following: restored-small, round pits, accompanied with honeycomb-like subepithelial capillary networks; atrophic-well-demarcated oval or tubulovillous pits with clearly visible coiled or wavy vessels. The subjects were also classified into the three types: Grade 0-restored pattern is shown in all or almost the entire area of gastric body; Grade 1-mixture of restored and atrophic pattern, there is a considerable portion of the atrophic area in the lesser curvature; Grade 2-atrophic pattern is shown in all or almost the entire area of the gastric body.

RESULTS

Sensitivity and specificity for atrophic type for detection of histological intestinal metaplasia were 95.9 and 98.3%, respectively. No association was observed between the prevalence of Grades 0, 1 and 2 and duration after eradication, while grades 1 and 2 were significantly frequent in gastric cancer patients diagnosed both before (27/35: 77%) and after (23/31: 74%) eradication, compared to the cancer-free subjects (15/59: 25%) (P < 0.001). The grades 1 and 2 were also common in patients who underwent H. pylori eradication for gastric ulcer.

CONCLUSIONS

Magnifying the NBI pattern well correlates with pathological status of gastric mucosa after H. pylori eradication and may predict gastric cancer occurrence.

Risk Stratification for Covert Invasive Cancer Among Patients Referred for Colonic Endoscopic Mucosal Resection: A Large Multicenter Cohort

BACKGROUND & AIMS

Among patients with large colorectal sessile polyps or laterally spreading lesions, it is important to identify those at risk for submucosal invasive cancer (SMIC). Lesions with overt endoscopic evidence of SMIC are referred for surgery, although those without these features might still contain SMIC that is not visible on endoscopic inspection (covert SMIC). Lesions with a high covert SMIC risk might be better suited for endoscopic submucosal dissection than for endoscopic mucosal resection (EMR). We analyzed a group of patients with large colon lesions to identify factors associated with SMIC, and examined lesions without overt endoscopic high-risk signs to determine factors associated with covert SMIC.

METHODS

We performed a prospective cohort study of consecutive patients referred for EMR of large sessile or flat colorectal polyps or laterally spreading lesions (≥20 mm) at academic hospitals in Australia from September 2008 through September 2016. We collected data on patient and lesion characteristics, outcomes of procedures, and histology findings. We excluded serrated lesions from the analysis of covert SMIC due to their distinct phenotype and biologic features.

RESULTS

We analyzed 2277 lesions (mean size, 36.9 mm) from 2106 patients (mean age, 67.7 years; 53.2% male). SMIC was evident in 171 lesions (7.6%). Factors associated with SMIC included Kudo pit pattern V, a depressed component (0-IIc), rectosigmoid location, 0-Is or 0-IIa+Is Paris classification, non-granular surface morphology, and increasing size. After exclusion of lesions that were obviously SMIC or serrated, factors associated with covert SMIC were rectosigmoid location (odds ratio, 1.87; P = .01), combined Paris classification, surface morphology (odds ratios, 3.96-22.5), and increasing size (odds ratio, 1.16/10 mm; P = .012).

CONCLUSIONS

In a prospective study of 2106 patients who underwent EMR for large sessile or flat colorectal polyps or laterally spreading lesions, we associated rectosigmoid location, combined Paris classification and surface morphology, and increasing size with increased risk for covert malignancy. Rectosigmoid 0-Is and 0-IIa+Is non-granular lesions have a high risk for malignancy, whereas proximally located 0-Is or 0-IIa granular lesions have a low risk. These findings can be used to inform decisions on which patients should undergo endoscopic submucosal dissection, EMR, or surgery. ClinicalTrials.gov, Number: NCT02000141.

Magnifying Endoscopy with Blue Laser Imaging Improves the Microstructure Visualization in Early Gastric Cancer: Comparison of Magnifying Endoscopy with Narrow-Band Imaging

BACKGROUNDS

Magnifying endoscopy with blue laser imaging (ME-BLI) for diagnosis of early gastric cancer (EGC) is as effective as magnifying endoscopy with narrow-band imaging (ME-NBI). However, there are different EGCs in microstructure visualization between ME-BLI and ME-NBI. This study aimed to clarify the pathological features of the EGCs, in which microstructure visualization was different between ME-NBI and ME-BLI.

METHODS

EGCs were classified into groups A (irregular microsurface pattern (MSP) in ME-BLI and absent MSP in ME-NBI), B (irregular MSP in two modalities), or C (absent MSP in two modalities), according to the vessel plus surface classification. We compared the pathological features of EGCs between the three groups.

RESULTS

17, four, and five lesions could be evaluated in detail in groups A, B and C, respectively. Well-differentiated adenocarcinomas with shallow crypts were more frequent in group A than in group B (58.8 and 0%, resp.). The mean crypt depth of group A was significantly shallower than that of group B (56 ± 20, 265 ± 64 μm, resp., P = 0.0002).

CONCLUSIONS

ME-BLI could better visualize the microstructures of the EGCs with shallow crypts compared with ME-NBI. Therefore, ME-BLI could enable a more accurate diagnosis of EGC with shallow crypts.

Endoscopic features of lymphoid follicles using blue laser imaging (BLI) endoscopy in the colorectum and its association with chronic bowel symptoms

Background/Aim

In the colorectum, lymphoid follicles hyperplasia (LH) is sometimes observed as small, round, yellowish-white nodules. The novel image-enhanced endoscopy system named blue laser imaging (BLI) provides enhanced the contrast of surface vessels using lasers for light illumination. We investigated the endoscopic features of LH observed by using BLI endoscopy and its association with chronic bowel symptoms.

Patients/Methods

300 participants undergoing colonoscopy for various indications were enrolled. Entire colorectum was observed by using BLI-bright mode with non-magnification view. LH was defined as well demarcated white nodules. Elevated LH with erythema was distinguished as LH severe.

Results

LHs were observed more clearly by using BLI-bright mode compared to conventional white light colonoscopy and were also histologically confirmed as intense infiltration of lymphocytes or plasmacytes. LH was observed in 134 subjects (44.6%) and 67 (22.3%) were LH severe. LH was associated younger age (Odds ratio (OR) = 1.05, 95%Confidence Interval (95%CI) = 1.03–1.07, P<0.0001) and chronic bowel symptoms including constipation, hard stools, diarrhea and loose stools (all LH: OR = 4.03, 95%CI = 2.36–6.89, P<0.0001, LH severe: OR = 5.31, 95%CI = 2.64–10.71, P<0.0001). LH severe was closely associated with both constipation associated symptoms (OR = 3.94, 95%CI = 1.79–8.66, P = 0.0007) and diarrhea associated symptoms (OR = 5.22, 95%CI = 2.09–13.05, P = 0.0004). In particular, LH severe in the ascending colon was strongly associated with bowel symptoms (P<0.0001).

Conclusion

LH, visualized by using BLI endoscopy was associated with bowel symptom, raising the possibility of pathogenic role of this endoscopic finding in the functional lower gastrointestinal disorders.

Effectiveness of computer-aided diagnosis of colorectal lesions using novel software for magnifying narrow-band imaging: a pilot study

BACKGROUND AND STUDY AIMS

 Magnifying narrow-band imaging (M-NBI) enables detailed observation of microvascular architecture and can be used in endoscopic diagnosis of colorectal lesion. However, in clinical practice, differential diagnosis and estimation of invasion depth of colorectal lesions based on M-NBI findings require experience. Therefore, developing computer-aided diagnosis (CAD) for M-NBI would be beneficial for clinical practice. The aim of this study was to evaluate the effectiveness of software for CAD of colorectal lesions.

MATERIALS AND METHODS

In collaboration with Yamaguchi University, we developed novel software that enables CAD of colorectal lesions using M-NBI images. This software for CAD further specifically divides original Sano's colorectal M-NBI classification into 3 groups (group A, capillary pattern [CP] type I; group B, CP type II + CP type IIIA; group C, CP type IIIB), which describe hyperplastic polyps (HPs), adenoma/adenocarcinoma (intramucosal [IM] to submucosal [SM]-superficial) lesions, and SM-deep lesions, respectively. We retrospectively reviewed 121 lesions evaluated using M-NBI.

RESULTS

The 121 reviewed lesions included 21 HP, 80 adenoma/adenocarcinoma (IM to SM-superficial), and 20 SM-deep lesions. The concordance rate between the CAD and the diagnosis of the experienced endoscopists was 90.9 %. The sensitivity, specificity, positive and negative predictive values, and accuracy of the CAD for neoplastic lesions were 83.9 %, 82.6 %, 53.1 %, 95.6 %, and 82.8 %, respectively. The values for SM-deep lesions were 83.9 %, 82.6 %, 53.1 %, 95.6 %, and 82.8 %, respectively.

CONCLUSION

 Relatively high diagnostic values were obtained using CAD. This software for CAD could possibly lead to a wider use of M-NBI in the endoscopic diagnosis of colorectal lesions.

A Benchmark for Endoluminal Scene Segmentation of Colonoscopy Images

Colorectal cancer (CRC) is the third cause of cancer death worldwide. Currently, the standard approach to reduce CRC-related mortality is to perform regular screening in search for polyps and colonoscopy is the screening tool of choice. The main limitations of this screening procedure are polyp miss rate and the inability to perform visual assessment of polyp malignancy. These drawbacks can be reduced by designing decision support systems (DSS) aiming to help clinicians in the different stages of the procedure by providing endoluminal scene segmentation. Thus, in this paper, we introduce an extended benchmark of colonoscopy image segmentation, with the hope of establishing a new strong benchmark for colonoscopy image analysis research. The proposed dataset consists of 4 relevant classes to inspect the endoluminal scene, targeting different clinical needs. Together with the dataset and taking advantage of advances in semantic segmentation literature, we provide new baselines by training standard fully convolutional networks (FCNs). We perform a comparative study to show that FCNs significantly outperform, without any further postprocessing, prior results in endoluminal scene segmentation, especially with respect to polyp segmentation and localization.

Recent advances in pediatric gastrointestinal endoscopy: an overview

Pediatric gastrointestinal endoscopy has become a fundamental component of health care for infants and children. New imaging technologies and creative extraluminal applications have brought exciting and clinically important benefits to pediatric gastrointestinal endoscopy. Areas covered: The impact of different new technologies in pediatric endoscopy and focused on improvements in mucosa visualization and the application of new noninvasive tools and procedures to avoid biopsies or surgery are reviewed. Expert commentary: Enhancement in mucosal visualization and reduction of anesthesia and biopsies are the main goals that guide the endoscopy development in pediatrics. The advent of newer imaging modalities has allowed clinicians to characterize and evaluate subtle mucosal lesions better, while advancements in current endoscopes have created the opportunity to monitor chronic conditions noninvasively. Continued expansion of these modalities seems certain, with increased utilization in pediatric gastroenterology.

Multicenter randomised controlled trial comparing the high definition white light endoscopy and the bright narrow band imaging for colon polyps

AIM

To compare high definition white light endoscopy and bright narrow band imaging for colon polyps' detection rates.

METHODS

Patients were randomised to high definition white light endoscopy (HD-WLE) or the bright narrow band imaging (bNBI) during withdrawal of the colonoscope. Polyps identified in either mode were characterised using bNBI with dual focus (bNBI-DF) according to the Sano's classification. The primary outcome was to compare adenoma detection rates (ADRs) between the two arms. The secondary outcome was to assess the negative predictive value (NPV) in differentiating adenomas from hyperplastic polyps for diminutive rectosigmoid lesions.

RESULTS

A total of 1006 patients were randomised to HD-WLE (n = 511) or bNBI (n = 495). The mean of adenoma per patient was 1.62 and 1.84, respectively. The ADRs in bNBI and HD-WLE group were 37.4% and 39.3%, respectively. When adjusted for withdrawal time (OR = 1.19, 95%CI: 1.15-1.24, P < 0.001), the use of bNBI was associated with a reduced ADR (OR = 0.69, 95%CI: 0.52-0.92). Nine hundred and thirty three polyps (86%) in both arms were predicted with high confidence. The sensitivity (Sn), specificity (Sp), positive predictive value and NPV in differentiating adenomatous from non-adenomatous polyps of all sizes were 95.9%, 87.2%, 94.0% and 91.1% respectively. The NPV in differentiating an adenoma from hyperplastic polyp using bNBI-DF for diminutive rectal polyps was 91.0%.

CONCLUSION

ADRs did not differ between bNBI and HD-WLE, however HD-WLE had higher ADR after adjustment of withdrawal time. bNBI surpassed the PIVI threshold for diminutive polyps.

Magnifying narrow-band imaging of gastric mucosal morphology predicts the H. pylori-related epigenetic field defect

DNA methylation is associated with "field defect" in the gastric mucosa. To characterize "field defect" morphologically, we examined DNA methylation of non-neoplastic gastric mucosa in relation to their morphology seen by narrow-band imaging (NBI) with magnifying endoscopy. Magnifying NBI of non-neoplastic gastric body was classified as follows: normal-small and round pits with uniform subepithelial capillary networks; type 1-a little enlarged round pits with indistinct subepithelial capillary networks; type 2-remarkably enlarged pits with irregular vessels; and type 3-clearly demarcated oval or tubulovillous pits with bulky coiled or wavy vessels. Methylation of nine candidate genes (MYOD1, SLC16A12, GDNF, IGF2, MIR 124A1, CDH1, PRDM5, RORA and MLF1) were determined by bisulfite pyrosequencing. Infinium HumanMethylation450 array was used to characterize the methylation of >450,000 CpG sites. Mean Z score methylation of nine genes positively correlated with the changes of mucosal patterns from normal to types 1, 2, and 3 (P < 0.0001). Genome-wide analysis showed that development of mucosal patterns correlated with methylation accumulation especially at CpG islands. Genes with promoter CpG islands that were gradually methylated with the development of mucosal patterns significantly enriched the genes involved in zinc-related pathways. The results indicates that gastric mucosal morphology predicts a "field defect" in this tissue type. Accumulation of DNA methylation is associated with "field defect" in the non-neoplastic gastric mucosa. Endoscopic identification of "field defect" has important implications for preventing gastric cancer. Our results suggest that magnifying NBI of gastric mucosal morphology predicts a "field defect" in the gastric mucosa.