High definition plus colonoscopy combined with i-scan tone enhancement vs. high definition colonoscopy for colorectal neoplasia: A randomized trial

Recent advances in devices and technologies that might prove revolutionary for colonoscopy procedures

INTRODUCTION

Colorectal cancer (CRC) is the third most common malignancy and second leading cause of cancer-related mortality in the world. Adenoma detection rate (ADR), a quality indicator for colonoscopy, has gained prominence as it is inversely related to CRC incidence and mortality. As such, recent efforts have focused on developing novel colonoscopy devices and technologies to improve ADR.

AREAS COVERED

The main objective of this paper is to provide an overview of advancements in the fields of colonoscopy mechanical attachments, artificial intelligence-assisted colonoscopy, and colonoscopy optical enhancements with respect to ADR. We accomplished this by performing a comprehensive search of multiple electronic databases from inception to September 2023. This review is intended to be an introduction to colonoscopy devices and technologies.

EXPERT OPINION

Numerous mechanical attachments and optical enhancements have been developed that have the potential to improve ADR and AI has gone from being an inaccessible concept to a feasible means for improving ADR. While these advances are exciting and portend a change in what will be considered standard colonoscopy, they continue to require refinement. Future studies should focus on combining modalities to further improve ADR and exploring the use of these technologies in other facets of colonoscopy.

Variability in adenoma detection rate in control groups of randomized colonoscopy trials: a systematic review and meta-analysis

BACKGROUND AND AIMS

Adenoma detection rate (ADR) is still the main surrogate outcome parameter of screening colonoscopy, but most studies include mixed indications, and basic ADR is quite variable. We therefore looked at the control groups in randomized ADR trials using advanced imaging or mechanical methods to find out whether indications or other factors influence ADR levels.

METHODS

Patients in the control groups of randomized controlled trials (RCTs) on ADR increase using various methods were collected based on a systematic review; this control group had to use high-definition white-light endoscopy performed between 2008 and 2021. Random-effects meta-analysis was used to pool ADR in control groups and its 95% confidence interval (CI) according to clinical (indication and demographic), study setting (tandem/parallel, number of centers, sample size), and technical (type of intervention, withdrawal time) parameters. Interstudy heterogeneity was reported with the I² statistic. Multivariable mixed-effects meta-regression was performed for potentially relevant variables.

RESULTS

From 80 studies, 25,304 patients in the respective control groups were included. ADR in control arms varied between 8.2% and 68.1% with a high degree of heterogeneity (I² = 95.1%; random-effect pooled value, 37.5%; 95% CI, 34.6‒40.5). There was no difference in ADR levels between primary colonoscopy screening (12 RCTs, 15%) and mixed indications including screening/surveillance and diagnostic colonoscopy; however, fecal immunochemical testing as an indication for colonoscopy was an independent predictor of ADR (odds ratio [OR], 1.6; 95% CI, 1.1-2.4). Other well-known parameters were confirmed by our analysis such as age (OR, 1.038; 95% CI, 1.004-1.074), sex (male sex: OR, 1.02; 95% CI, 1.01-1.03), and withdrawal time (OR, 1.1; 95% CI, 1.0-1.1). The type of intervention (imaging vs mechanical) had no influence, but methodologic factors did: More recent year of publication and smaller sample size were associated with higher ADR.

CONCLUSIONS

A high level of variability was found in the level of ADR in the control groups of RCTs. With regards to indications, only fecal immunochemical test-based colonoscopy studies influenced basic ADR, and primary colonoscopy screening appeared to be similar to other indications. Standardization for variables related to clinical, methodologic, and technical parameters is required to achieve generalizability and reproducibility.

Electronic chromo-endoscopy: technical details and a clinical perspective

Precise endoscopic assessment is necessary to detect neoplastic changes in an early stage. Electronic or virtual chromo-endoscopy (ECE) is an alternative to conventional dye-based chromo-endoscopy which markedly improves capillary pattern and hence can detect micro-vessel morphological changes of early neoplasia to target biopsies and aid in diagnosis. The clinical significance increased after the advent of endoscopic treatment modalities like ESD/EMR which requires precise delineation of extent and depth of lesion. Most of the studies have used narrow-band imaging (NBI) (Olympus Medical Systems Tokyo, Japan), although data from i-SCAN (PENTAX Endoscopy, Tokyo, Japan) and flexible spectral imaging color enhancement (FICE) (Fujinon, Fujifilm Medical Co, Saitama, Japan) are emerging. Electronic chromo-endoscopy is convenient compared to dye-based chromo-endoscopy in the sense that it is available at the push of a button in endoscope and reduces procedure time substantially with comparable efficacy. Scope of this review is to discuss available electronic chromo-endoscopy modalities and their role in the diagnosis, surveillance, and management of early GI neoplasia.

Can image-enhanced endoscopy improve adenoma detection rate?

An accumulating body of evidence has shown that detection and resection of pre-cancerous adenoma by colonoscopy could effectively prevent colorectal cancer (CRC) and its related mortality. Among various colonoscopy quality indicators, such as cecal intubation rate, withdrawal time, and adenoma detection rate (ADR); ADR is the most important and most closely associated with the subsequent risk of CRC. Image-enhanced endoscopy (IEE), including digital and dye-based IEE, was originally developed to discriminate neoplastic from non-neoplastic lesions but later studies have demonstrated that it can also enhance lesion detection by enhancing the contrast between the lesion and background colonic mucosa. Nevertheless, using IEE in colonoscopy for lesion detection is still not the standard way of practice in the real world. For a better understanding of current IEE modalities, this review introduces and compares the currently available IEE modalities and their efficacy in detecting adenoma from the results of randomized controlled trials or meta-analyses.

Designs of colonoscopic adenoma detection trials: more positive results with tandem than with parallel studies - an analysis of studies on imaging techniques and mechanical devices

BACKGROUND AND AIMS

Adenoma detection rate (ADR) has been shown to correlate with interval cancers after screening colonoscopy and is commonly used as surrogate parameter for its outcome quality. ADR improvements by various techniques have been studied in randomised trials using either parallel or tandem methodololgy.

METHODS

A systematic literature search was done on randomised trials (full papers, English language) on tandem or parallel studies using either adenoma miss rates (AMR) or ADR as main outcome to test different novel technologies on imaging (new endoscope generation, narrow band imaging, iScan, Fujinon intelligent chromoendoscopy/blue laser imaging and wide angle scopes) and mechanical devices (transparent caps, endocuff, endorings and balloons). Available meta analyses were also screened for randomised studies.

RESULTS

Overall, 24 randomised tandem trials with AMR (variable definitions and methodology) and 42 parallel studies using ADR (homogeneous methodology) as primary outcome were included. Significant differences in favour of the new method were found in 66.7% of tandem studies (8222 patients) but in only 23.8% of parallel studies (28 059 patients), with higher rates of positive studies for mechanical devices than for imaging methods. In a random-effects model, small absolute risk differences were found, but these were double in magnitude for tandem as compared with parallel studies (imaging: tandem 0.04 (0.01, 0.07), parallel 0.02 (0.00, 0.04); mechanical devices: tandem 0.08 (0.00, 0.15), parallel 0.04 (0.01, 0.07)). Nevertheless, 94.2% of missed adenomas in the tandem studies were small (<1 cm) and/or non-advanced.

CONCLUSIONS

A tandem study is more likely to yield positive results than a simple parallel trial; this may be due to the use of different parameters, variable definitions and methodology, and perhaps also a higher likelihood of bias. Therefore, we suggest to accept positive results of tandem studies only if accompanied by positive results from parallel trials.

Advanced Endoscopic Imaging in Colonic Neoplasia

BACKGROUND

Endoscopic imaging is a rapidly evolving field with a constant influx of new concepts and technologies. Since the introduction of video endoscopy and subsequently high-definition imaging as the first revolutions in gastrointestinal endoscopy, several technologies of virtual chromoendoscopy have been developed and brought to the market in the past decade, which have shaped and revolutionized for a second time our approach to endoscopic imaging. In parallel to these developments, microscopic imaging technologies, such as endomicroscopy and endocytoscopy, allow us to examine single cells within the mucosa in real time, thereby enabling histological diagnoses during ongoing endoscopy.

SUMMARY

In this review, we provide an overview on the technical background of different technologies of advanced endoscopic imaging, and then review and discuss their role and applications for the diagnosis and management of colorectal neoplasms as well as limitations and challenges that exist despite all technological improvements.

KEY MESSAGES

Technologies of advanced endoscopic imaging have profound impact not only on our imaging capabilities, they are also about to fundamentally change our approach to managing lesions in the gastrointestinal tract: not every lesion found during colonoscopy has to be excised or sent for histopathologic evaluation. However, before this becomes widespread reality, major obstacles such as patient acceptance, adoption by less trained endoscopists, and also legal aspects need to carefully addressed. The development of computer-aided diagnosis and artificial intelligence algorithms hold the potential to overcome the obstacles associated with the concept of optical biopsy and will most likely fundamentally facilitate, shape, and change decision making in the management of colorectal lesions.

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.

Virtual Chromoendoscopy With FICE for the Classification of Polypoid and Nonpolypoid Raised Lesions in Ulcerative Colitis

GOALS

The aim of this study was to analyze the performance of Fuji Intelligent Color Enhancement (FICE) using the classification of Kudo in the differentiation of neoplastic and non-neoplastic raised lesions in ulcerative colitis (UC).

BACKGROUND

The Kudo classification of mucosal pit patterns is an aid for the differential diagnosis of colorectal polyps in the general population, but no systematic studies are available for all forms of raised lesions in UC.

STUDY

All raised, polypoid and nonpolypoid, lesions found during consecutive surveillance colonoscopies with FICE for long-standing UC were included. In the primary prospective analysis, the Kudo classification was used to predict the histology by FICE. In a post hoc analysis, further endoscopic markers were also explored.

RESULTS

Two hundred and five lesions (mean size, 8 mm; range, 2 to 30 mm) from 59 patients (mean age, 56 y; range, 21 to 79 y) were analyzed. Twenty-three neoplastic (11%), 18 hyperplastic (9%), and 164 inflammatory (80%) lesions were found. Thirty-one lesions (15%), none of which were neoplastic, were unclassifiable according to Kudo. After logistic regression, a strong negative association resulted between endoscopic activity and neoplasia, whereas the presence of a fibrin cap was significantly associated with endoscopic activity. Using FICE, the sensitivity, specificity, and positive and negative likelihood ratios of the Kudo classification were 91%, 76%, 3.8, and 0.12, respectively. The corresponding values by adding the fibrin cap as a marker of inflammation were 91%, 93%, 13, and 0.10, respectively.

CONCLUSIONS

FICE can help to predict the histology of raised lesions in UC. A new classification of pit patterns, based on inflammatory markers, should be developed in the setting of UC to improve the diagnostic performance.

Effect of I-scan Electronic Chromoendoscopy on Detection of Adenomas During Colonoscopy

BACKGROUND & AIMS

I-scan is an electronic chromoendoscopy technology that improves resolution of epithelial and mucosal surfaces and vessels. We performed a randomized controlled trial to compare detection of adenomas by i-scan vs standard high-definition white-light (HDWL) colonoscopy.

METHODS

From February 1 through December 31, 2017, 740 outpatients (50-75 years old) undergoing screening and surveillance for colorectal neoplasia were randomly assigned to groups that received colonoscopies with i-scan 1 (surface and contrast enhancement) or HDWL. When lesions and polyps were detected, endoscopists could switch between i-scan 1 and HDWL imaging to confirm their finding; polyps were collected and analyzed by histology. The primary outcome was adenoma detection rate (ADR, proportion of subjects with at least 1 adenoma of any size); secondary outcomes included detection of sessile serrated polyps and neoplasias, along with location, size, and morphology of polyps. We performed intent to treat and per-protocol analyses (on 357 patients evaluated by i-scan and 358 evaluated by HDWL colonoscopy) to assess the primary and secondary outcomes.

RESULTS

There were no differences in baseline characteristics between the groups. In the intent to treat analysis, the ADR was significantly higher in the i-scan 1 group (47.2%) than in the HDWL colonoscopy group (37.7%) (P = .01). In the per-protocol analysis, the ADR in the i-scan 1 group (47.6%) was also significantly higher than in the HDWL group (37.2%) (P = .005), but this effect was not consistent among all endoscopists. There was no difference between groups in detection of sessile serrated polyps. However, the rate of neoplasia detection was significantly higher in the i-scan 1 group (56.4%) than in the than the HDWL group (46.1%) (P = .005). In secondary analyses, the increase in ADR was associated with improved detection of diminutive flat adenomas in the right colon.

CONCLUSION

In a prospective randomized trial, higher proportions of patients with adenomas were identified in a group that underwent colonoscopy with i-scan 1 than in a group evaluated by HDWL colonoscopy. This effect was mainly due to improved detection of diminutive, flat right sided adenomas. I-scan 1 technology may benefit some endoscopists. ClinicalTrials.gov no: NCT02811419.

No Interval Cancers in Endoscopic Practice

Colonoscopy is long time the most preferred method for CRC screening along with diagnosis and treatment for a range of colon diseases. Based on its difficulty in visualizing precursor CRC lesions, mostly those located on the right colon, this method can be subject of improvement. The colonoscopy quality can be influenced by many factors such as colon preparation, retraction time, the colonoscopists medical training and knowledges as well as the performance of endoscopy equipment. The bad quality of colonoscopy will result in the emergence of interval cancers defined, based on the author, as cancers that appear at 3-5 years up to 10 years from the colonoscopy procedure. Interval cancers have predominantly incriminated both the colonoscopy quality and the clinician competences and less the tumor biology. Subsequently there were set quality indicators of colonoscopy in order to raise the quality of the exploration. Among the important indicators, proving their utility in studies, the ADR (adenoma detection rate) is most commonly used along with PDR (polyp detection rate) and APC (adenoma per colonoscopy). Following the purpose of obtaining a higher colonoscopy quality the medical units should keep in check all indicators. Furthermore, there should be an active involvement in an additional training of non-conforming medical personnel or even restrain of practice, given the medical legal actions that have interval cancers as a main cause.

Leaving colorectal polyps in place can be achieved with high accuracy using blue light imaging (BLI)

Objectives

A negative predictive value of more than 90% is proposed by the American Society of Gastrointestinal Endoscopy Preservation and Incorporation of Valuable Endoscopic Innovations (PIVI) statement for a new technology in order to leave distal diminutive colorectal polyps in place without resection. To our knowledge, no prior prospective study has yet evaluated the feasibility of the most recently introduced blue light imaging (BLI) system for real-time endoscopic prediction of polyp histology for the specific endpoint of leaving hyperplastic polyps in place.

Aims

Prospective assessment of real-time prediction of colorectal polyps by using BLI.

Material and methods

In total, 177 consecutive patients undergoing screening or surveillance colonoscopy were included. Colorectal polyps were evaluated in real-time by using high-definition endoscopy and the BLI technology without optical magnification. Before resection, the endoscopist described each polyp according to size, shape and surface characteristics (pit and vascular pattern, colour and depression), and histology was predicted with a level of confidence (high or low).

Results

Histology was predicted with high confidence in 92.5% of polyps. Sensitivity of BLI for prediction of adenomatous histology was 92.68%, with a specificity and accuracy of 94.87 and 93.75%, respectively. Following the recommendation of the PIVI statement, positive and negative predictive values were calculated with values of 95 and 92.5%, respectively. Prediction of surveillance based on both US and European guidelines was correctly predicted in 91% of patients.

Conclusion

The most recently introduced BLI technology is accurate enough to leave distal colorectal polyps in place without resection. BLI also allowed for assignment of postpolypectomy surveillance intervals. This approach therefore has the potential to reduce costs and risks associated with the redundant removal of diminutive colorectal polyps.

G-EYE advanced colonoscopy for improved polyp detection rates - a randomized tandem pilot study with different endoscopists

BACKGROUND AND AIMS

 The most commonly missed polyps in colonoscopy are those located behind haustral folds. The G-EYE system is a standard colonoscope consisting of re-processable balloon at its distal tip. The G-EYE balloon improves the detection of polyps by straightening the haustral folds. In our back-to-back tandem study, we aimed to determine whether and to what extent the G-EYE system could reduce adenoma miss rates in screening colonoscopy.

METHODS

 Patients referred to colonoscopy were randomized into 2 groups. Group A underwent a standard colonoscopy (SC) followed by balloon colonoscopy (BC), and Group B underwent BC followed by SC. In this randomized tandem study, the investigator's level of training and the endoscopists themselves were changed after each withdrawal. Each endoscopist was blinded to the results of the first withdrawal.

RESULTS

 Fifty-eight patients were enrolled and randomized into 2 groups with similar baseline characteristics. Nine patients were excluded from the study. Twenty-five patients underwent SC followed by BC while 24 underwent BC followed by SC. The adenoma miss rate for SC was 41 %, with an additional detection rate of 69 % for BC (ratio 1.69). The overall miss rate for polyps was 60 % for SC, with an additional detection rate of 150 % for BC (ratio 2.5). Experienced investigators who used BC were able to identify an additional 7 polyps while inexperienced investigators.

CONCLUSIONS

 Although our results could not clearly confirm that BC improves adenoma detection, the investigator's experience appears to be a major determinant of the adenoma detection rate.

High-definition i-Scan colonoscopy is superior in the detection of diminutive polyps compared with high-definition white light colonoscopy: a prospective randomized-controlled trial

INTRODUCTION

Recognition of flat and small neoplastic lesions by colonoscopy is still challenging. High-definition (HD) i-Scan colonoscopy is a promising technique to maximize the sensitivity of colonoscopy; however, whether i-Scan can increase the detection rate of polyps is still unclear. The aim of this study was to prospectively compare HD i-Scan colonoscopy with HD colonoscopy for the detection rate of polyps in routine practice.

MATERIALS AND METHODS

A total of 449 patients who underwent total colonoscopy for the first time were randomized in a 1 : 1 ratio to undergo HD+i-Scan colonoscopy or HD colonoscopy. Detected colorectal polyps were judged according to type, location, and size. The primary endpoint was the detection rate and the total number of polyps.

RESULTS

The number of polyps identified in the HD+i-Scan group was significantly higher than that in the HD group (P=0.041), and this difference was more obvious for diminutive polyps (P=0.035). The number of patients with at least one polyp was not significantly different between the two groups irrespective of the size or the location. Overall, 268 polyps were removed, 130 in the HD+i-Scan group and 138 in the HD group. Among these, three high-grade intraepithelial neoplasia were found in diminutive polyps.

CONCLUSION

HD+i-Scan colonoscopy is superior to HD colonoscopy in detecting diminutive polyps on the basis of this prospective randomized-controlled trial.

FICE in Predicting Colorectal Flat Lesion Histology

BACKGROUND AND OBJECTIVES

Colonoscopy is the gold standard for detection of polyps and is preventive against colorectal cancers. Flat adenomas are small, superficial lesions and have a high rate of going undetected during conventional white-light endoscopy. This article adds to the scant body of literature in English regarding in vivo detection and diagnosis of flat adenomas using Fujinon intelligent color enhancement (FICE) system. In this study, we investigated the diagnosis of flat lesions via the FICE endoscopy system and in vivo histologic diagnostic estimations of flat lesions.

METHODS

This prospective study was conducted in patients who underwent colonoscopy that found flat adenomas. Lesions were classified morphologically with regard to the Paris Classification and sent for histopathologic examination after in vivo histologic diagnostic estimations were made according to Kudo's pit pattern classification. The positive predictive value (PPV), negative predictive value (NPV), specificity, sensitivity, and accuracy of in vivo endoscopic diagnostic estimations of flat lesions with the FICE system were analyzed.

RESULTS

A total of 217 flat lesions were identified in 137 patients. Of the lesions, 85.7% were Paris type 0-IIa, and 59.4% were Kudo pit pattern type III. When the FICE diagnostic estimations of flat lesions and final pathology results were considered, PPV was 68.5%, NPV value was 89.6%, sensitivity was 94.7%, specificity was 50.9%, and accuracy was 74.2%.

CONCLUSIONS

Biologic importance of flat lesions is obscure, as they are usually missed during colonoscopy. The use of novel endoscopic techniques may improve their detection and diagnosis rates.

British Society of Gastroenterology position statement on serrated polyps in the colon and rectum

Serrated polyps have been recognised in the last decade as important premalignant lesions accounting for between 15% and 30% of colorectal cancers. There is therefore a clinical need for guidance on how to manage these lesions; however, the evidence base is limited. A working group was commission by the British Society of Gastroenterology (BSG) Endoscopy section to review the available evidence and develop a position statement to provide clinical guidance until the evidence becomes available to support a formal guideline. The scope of the position statement was wide-ranging and included: evidence that serrated lesions have premalignant potential; detection and resection of serrated lesions; surveillance strategies after detection of serrated lesions; special situations-serrated polyposis syndrome (including surgery) and serrated lesions in colitis; education, audit and benchmarks and research questions. Statements on these issues were proposed where the evidence was deemed sufficient, and re-evaluated modified via a Delphi process until >80% agreement was reached. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) tool was used to assess the strength of evidence and strength of recommendation for finalised statements. Key recommendation: we suggest that until further evidence on the efficacy or otherwise of surveillance are published, patients with sessile serrated lesions (SSLs) that appear associated with a higher risk of future neoplasia or colorectal cancer (SSLs ≥10 mm or serrated lesions harbouring dysplasia including traditional serrated adenomas) should be offered a one-off colonoscopic surveillance examination at 3 years (weak recommendation, low quality evidence, 90% agreement).

Tri-Scan: A Three Stage Color Enhancement Tool for Endoscopic Images

Modern endoscopes play a significant role in diagnosing various gastrointestinal (GI) tract related diseases where the visual quality of endoscopic images helps improving the diagnosis. This article presents an image enhancement method for color endoscopic images that consists of three stages, and hence termed as "Tri-scan" enhancement: (1) tissue and surface enhancement: a modified linear unsharp masking is used to sharpen the surface and edges of tissue and vascular characteristics; (2) mucosa layer enhancement: an adaptive sigmoid function is employed on the R plane of the image to highlight micro-vessels of the superficial layers of the mucosa and submucosa; and (3) color tone enhancement: the pixels are uniformly distributed to create an enhanced color effect to highlight the subtle micro-vessels, mucosa and tissue characteristics. The proposed method is used on a large data set of low contrast color white light images (WLI). The results are compared with three existing enhancement techniques: Narrow Band Imaging (NBI), Fuji Intelligent Color Enhancement (FICE) and i-scan Technology. The focus value and color enhancement factor show that the enhancement level achieved in the processed images is higher compared to NBI, FICE and i-scan images.

Expert opinions and scientific evidence for colonoscopy key performance indicators

Colonoscopy is a widely performed procedure with procedural volumes increasing annually throughout the world. Many procedures are now performed as part of colorectal cancer screening programmes. Colonoscopy should be of high quality and measures of this quality should be evidence based. New UK key performance indicators and quality assurance standards have been developed by a working group with consensus agreement on each standard reached. This paper reviews the scientific basis for each of the quality measures published in the UK standards.

Electronic Imaging in Colonoscopy: Clinical Applications and Future Prospects

Electronic chromoendoscopy (EC) is an equipment-based technology which could be easily activated by push of a button. There are four EC techniques available for use at present: narrow band imaging (NBI), i-Scan, flexible spectral chromoendoscopy and blue laser imaging. Out of the four techniques, NBI has been extensively evaluated for the detection and characterization of dysplasia in colonic polyps and dysplasia associated with inflammatory bowel disease. In this review, we will focus on the new developments and applications of EC.

Seeing better - Evidence based recommendations on optimizing colonoscopy adenoma detection rate

Colorectal cancer is one of the three most frequent causes of cancer deaths in men and women in Europe and North America. Diagnosis and resection of adenomas has convincingly demonstrated its utility in diminishing colorectal cancer incidence. Therefore, colonoscopy is now the gold standard for colorectal cancer screening. But it is also known that colonoscopy effectiveness varies among endoscopists. Among different quality indicators, the most used is the adenoma detection rate (ADR) which is the percentage of average-risk patients for colorectal cancer who are found to have at least one adenoma or adenocarcinoma during a screening colonoscopy. There is compelling evidence supporting an inverse correlation between ADR and interval colorectal cancer (cancer found after a screening colonoscopy). Many factors such as quality of precolonoscopy preparation, additional observers, manoeuvres with the endoscope (second view, retroflexion, water inflation rather than air), time spent during withdrawal, changes in patient position, fold-flattener devices, new imaging or endoscopic modalities and use of intravenous or through the scope sprayed drugs, have been studied and developed with the aim of increasing the ADR. This reviews discusses these factors, and the current evidence, to “see better” in the colon and optimize ADR.

Increased Detection of Colorectal Polyps in Screening Colonoscopy Using High Definition i-SCAN Compared with Standard White Light

Background/Aims:

The aim of this study was to evaluate the efficacy of high definition (HD) i-SCAN for colorectal polyp detection in screening colonoscopy.

Methods:

We retrospectively analyzed the records of 501 patients who had undergone screening colonoscopy performed by three endoscopists with either HD i-SCAN (n=149) or standard white light (n=352) from January 2, 2014 through June 30, 2014. Patient information and inter-endoscopist variation as well as polyp number, endoscopic findings, and pathologic characteristics were reviewed.

Results:

The detection rates of colorectal and neoplastic polyps were significantly higher using HD i-SCAN than standard white light colonoscopy (52% vs. 38.1%, p=0.004 for colorectal polyps; and 37.2% vs. 27.9%, p=0.041 for neoplastic polyps). Analysis of endoscopic findings revealed no difference in detected polyp size between HD i-SCAN and standard white light colonoscopy (4.59±2.35 mm vs. 4.82±2.81 mm, p=0.739), but non-protruding polyps were more commonly detected by i-SCAN than by standard white light colonoscopy (24.6% vs. 13.5%, p=0.007).

Conclusions:

Colonoscopy using HD i-SCAN had a significantly higher detection rate of colorectal polyps, including neoplastic polyps, because of improved sensitivity for detecting non-protruding lesions.

Diagnostic value of high definition magnifying endoscopy combined with i-scan electronic staining in early gastric cancer

AIM: To evaluate the diagnostic value of high-definition magnifying endoscopy (HD-ME) combined with i-scan electronic staining in early gastric cancer.

METHODS: Seventy patients with suspected gastric cancer treated at Wuxi City People's Hospital from January 2011 to December 2013 were included. All patients underwent HD-ME combined with i-scan electronic staining. Using surgical biopsy as the gold standard, the diagnostic performance of HD-ME combined with i-scan electronic staining was evaluated.

RESULTS: Pathological analysis revealed 50 cases of benign lesions and 20 cases of malignant lesions. By HD-ME combined with i-scan electronic staining, 48 cases were diagnosed to be benign lesions and 22 cases to be malignant lesions. The sensitivity and specificity of HD-ME combined with i-scan electronic staining were 95.0% and 94.0%, respectively, and there was a good consistency between HD-ME combined with i-scan electron staining and histologic diagnosis (Kappa = 0.825). Of 20 patients with early gastric cancer, 8 underwent endoscopic submucosal dissection, and 12 were treated by surgery. The consistency between HD-ME combined with i-scan electron staining and histology in assessing the depth of invasion was 90.0% (Kappa = 0.981).

CONCLUSION: HD-ME combined with i-scan electron staining has good diagnostic performance and relatively high diagnostic sensitivity and specificity in early gastric cancer.

Chromocolonoscopy

Chromoendoscopy techniques improve the visualization of mucosal structures. This article reviews and summarizes key studies addressing the impact of chromoendoscopy on colonic neoplasia detection and differentiation of neoplastic from non-neoplastic polyps in average and high-risk populations, including patients with colonic inflammatory bowel disease (IBD). In this context, there are convincing data that chromoendoscopy differentiates neoplastic from non-neoplastic polyps in average-risk populations with high accuracy. Moreover, dye-based chromoendoscopy improves neoplasia detection in colonic IBD surveillance.

Can I improve my adenoma detection rate?

Adenoma detection rate (ADR) has emerged as a key quality metric for colonoscopy. Despite limitations, its major strength is based on its proven correlation with interval colorectal cancer. This has prompted extensive efforts to identify factors and interventions that improve ADR. Potentially modifiable factors that may influence ADR can be patient related (eg, bowel preparation), endoscopist related (eg, withdrawal time, quality of mucosal inspection, additional observers), or procedure related (eg, water infusion, additional examination of right colon, change in position, antispasmodics, colonoscopic equipment, and accessories). Providing endoscopists with educational material and/or feedback also seems to improve ADR.