High-definition and high-magnification endoscopes

Colorectal Neoplasia in the Setting of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is associated with an increased risk of colorectal cancer (colorectal adenocarcinoma [CRC]) compared with the general population. IBD-related CRC is related to poorer outcomes than non-IBD-related CRC, and it accounts for 10% to 15% of death in patients with IBD. As such, screening guidelines have been made specific to this population recommending shorter intervals of endoscopic screening to detect dysplasia and CRC relative to the general population. Advances in endoscopic technology allow for improved visualization of dysplasia, which has led to widespread adoption of dye-spray chromoendoscopy with targeted biopsy.

Endoscopic characterization of neoplastic and non-neoplastic lesions in inflammatory bowel disease: systematic review in the era of advanced endoscopic imaging

Background

Current guidelines strongly recommend the use of validated classifications to support optical diagnosis of lesions with advanced endoscopic imaging in the lower gastrointestinal tract. However, the optimal strategy in inflammatory bowel disease (IBD) is still a matter of debate.

Objectives

To analyze the accuracy of endoscopic classifications or single predictors for in vivo lesion characterization during endoscopic surveillance of IBD with advanced endoscopic imaging.

Design

Systematic review.

Data sources and methods

Medline and PubMed were used to extract all studies which focused on lesion characterization of neoplastic and non-neoplastic lesions in IBD. The diagnostic accuracy of endoscopic classifications and single endoscopic predictors for lesion characterization were analyzed according to type of patients, lesions, and technology used. When available, the rates of true and false positives or negatives for neoplasia were pooled and the sensitivity (SE), specificity (SP), positive predictive value, and negative predictive value (NPV) were calculated.

Results

We included 35 studies (2789 patients; 5925 lesions - 1149 neoplastic). Advanced endoscopic imaging included dye-based chromoendoscopy, virtual chromoendoscopy (VCE), magnification and high-definition endoscopy, confocal laser endomicroscopy (CLE), endocytoscopy, and autofluorescence imaging. The Kudo classification of pit patterns was most frequently used, with pooled SE 83%, SP 83%, and NPV 95%. The endoscopic criteria with the highest accuracy, with minimum SE ⩾ 90%, SP ⩾ 80%, and NPV ⩾ 90% were: the Kudo-IBD classification used with VCE (Fuji Intelligent Color Enhancement and i-SCAN); combined irregular surface and vascular patterns used with narrow band imaging; the Mainz classification used with CLE. Multiple clinical and technical factors were found to influence the accuracy of optical diagnosis in IBD.

Conclusion

No single endoscopic factor has yet shown sufficient accuracy for lesion characterization in IBD surveillance. Conventional classifications developed in the non-IBD setting have lower accuracy in IBD. The use of new classifications adapted for IBD (Kudo-IBD), and new technologies based on in vivo microscopic analysis show promise.

Intraoperative Anastomotic Evaluation Methods: Rigid Proctoscopy Versus Flexible Endoscopy

INTRODUCTION

Rigid proctosigmoidoscopy (RP) and flexible sigmoidoscopy (FS) are two modalities commonly used for intraoperative evaluation of colorectal anastomoses. This study seeks to determine whether there is an association between the endoscopic modality used to evaluate colorectal anastomoses and the rate of anastomotic leak (AL), organ space infection, and overall infectious complication.

METHODS

The 2012-2018 American College of Surgeons National Surgical Quality Improvement Program database was queried for patients undergoing colorectal anastomoses. Anastomotic evaluation method (RP versus FS) was identified by Current Procedural Terminologycoding and used for group classification. Outcomes measured included AL, organ space infections, and overall infection. Multivariable logistic regression analysis for predicting AL was performed.

RESULTS

We identified 7100 patients who underwent a colorectal anastomosis with intraoperative endoscopic evaluation. RP was utilized in 3397 (47.8%) and FS in 3703 (52.2%) patients. RP was used more commonly in diverticulitis (44.5% versus 36.2%, P < 0.01), while FS was used more frequently in malignancy (47.5% versus 36.7%, P < 0.01). Anastomotic evaluation with FS was associated with lower rates of organ space infection (3.8% versus 4.8%, P = 0.025) and AL (2.9% versus 3.8%, P = 0.028) compared to RP. On multivariate logistic regression modeling, anastomotic evaluation with RP was associated with a higher risk of AL (odds ratio 1.403, 95% CI 1.028-1.916, P = 0.033) compared to FS.

CONCLUSIONS

Compared to FS, rigid proctosigmoidoscopic evaluation of a colorectal anastomosis was associated with an increased rate of AL and organ space infection.

Evaluation of The Three-Dimensional Endoscopy in Basic and Extended Nasal Procedures: A Clinical and Cadaveric Study

Introduction  The three-dimensional (3D) endoscope is considered a new surgical tool used in different approaches in intranasal and anterior skull base surgical procedures. There are many advantages of 3D over two-dimensional (2D) endoscopy that have been demonstrated in clinical applications, surgical training, and different experimental studies. Objective  To show the difference between using the 3D and 2D endoscopes during endonasal and anterior skull base surgery and its importance. Methods  Our study is divided into two phases (clinical and cadaveric phases). In the clinical study we, have performed 52 endonasal and anterior skull base surgical procedures (26 study cases and 26 control cases). We recorded accuracy, duration, and intraoperative complication for each case. The cadaveric study was performed on three cadavers. Differences in accuracy and dissection time were recorded using 3D and 2D endoscopy for each side chosen by randomization. Results  In the clinical study, the cases done by 3D endoscope were significantly faster and more accurate with less intraoperative complications compared with cases done using 2D endoscope. In cadaveric dissection, while using 3D endoscope, there was better depth of perception regarding the anatomical landmarks compared with 2D endoscope. Conclusion  Three-dimensional endoscopy is an advanced instrument that allows better training for the coming generation of ear, nose, and throat surgeons. Both clinical and cadaveric studies offer a promising outcome in both endonasal and anterior skull base surgery.

Gastric Intestinal Metaplasia: Challenges and the Opportunity for Precision Prevention

GIM is a persistent, premalignant lesion whereby gastric mucosa is replaced by metaplastic mucosa resembling intestinal tissue, arising in the setting of chronic inflammation, particularly in the context of Helicobacter pylori. While the overall rates of progression to gastric adenocarcinoma are low, estimated at from 0.25 to 2.5%, there are features that confer a much higher risk and warrant follow-up. In this review, we collate and summarise the current knowledge regarding the pathogenesis of GIM, and the clinical, endoscopic and histologic risk factors for cancer. We examine the current state-of-practice with regard to the diagnosis and management of GIM, which varies widely in the published guidelines and in practice. We consider the emerging evidence in population studies, artificial intelligence and molecular markers, which will guide future models of care. The ultimate goal is to increase the detection of early gastric dysplasia/neoplasia that can be cured while avoiding unnecessary surveillance in very low-risk individuals.

Endoscopic Imaging for the Diagnosis of Neoplastic and Pre-Neoplastic Conditions of the Stomach

Gastric cancer is an aggressive disease with low long-term survival rates. An early diagnosis is essential to offer a better prognosis and curative treatment. Upper gastrointestinal endoscopy is the main tool for the screening and diagnosis of patients with gastric pre-neoplastic conditions and early lesions. Image-enhanced techniques such as conventional chromoendoscopy, virtual chromoendoscopy, magnifying imaging, and artificial intelligence improve the diagnosis and the characterization of early neoplastic lesions. In this review, we provide a summary of the currently available recommendations for the screening, surveillance, and diagnosis of gastric cancer, focusing on novel endoscopy imaging technologies.

Accuracy and Inter-observer Agreement Among Endoscopists for Visual Identification of Colorectal Polyps Using Endoscopy Images

BACKGROUND

It is essential to accurately distinguish small benign hyperplastic colon polyps (HP) from sessile serrated lesions (SSL) or adenomatous polyps (TA) based on endoscopic appearances. Our objective was to determine the accuracy and inter-observer agreements for the endoscopic diagnosis of small polyps.

METHODS

High-quality endoscopic images of 30 small HPs, SSLs, and TAs were used randomly to create two-timed PowerPoint slide sets-one with and another one without information on polyp size and location. Seven endoscopists viewed the slides on two separate occasions 90 days apart, identified the polyp type, and graded their confidence level. Overall and polyp-specific accuracies were assessed for the group and individual endoscopists. Chi-square tests and Kappa (κ) statistics were used to compare differences as appropriate.

RESULTS

When polyp size and location were provided, overall accuracy was 67.1% for TAs, 50.0% for SSLs, and 41.4% for HPs; the corresponding accuracies were 60%, 44.3%, and 34.3% when polyp size and location were withheld (p < .001). Inter-observer agreement was moderate for TAs (κ = 0.50) and fair for SSLs (κ = 0.26) and HPs (κ = 0.29); the corresponding inter-observer agreements were 0.44, 0.31, and 0.17 with polyp size and location withheld. Accuracy was not affected by knowledge of polyp size, location, or confidence level. Endoscopists with ≥ 10 years (vs. < 10 years) of colonoscopy experience had marginally higher (56% vs. 40%, p = 0.05) accuracy for SSL diagnosis.

CONCLUSIONS

The ability to distinguish between small TAs, SSLs, and HPs on their endoscopic appearance is poor regardless of the endoscopists' knowledge of polyp size and location.

Comparison of adenoma detection rate between high-definition colonoscopes with different fields of view: 170 degrees versus 140 degrees

In newer generation colonoscopes, the field of view (FOV) varies approximately between 170° and 140°, depending on the type of colonoscopy. To the best of our knowledge, no study has investigated whether the visual field difference of the colonoscope affects quality indicators, such as the adenoma detection rate (ADR), without using additional devices to expand the FOV in colonoscopes with the same resolution. This study aimed to investigate the difference in quality indicators, such as ADR, between 170° and 140° FOV in colonoscopes with the same high-definition resolution. We retrospectively analyzed the medical records of patients who underwent screening or surveillance colonoscopy at the Dong-A University Hospital in Busan, South Korea, between March 2021 and February 2022. We calculated the overall ADR ratios for patients who underwent colonoscopy with 140° and 170° FOV. Polyp detection rate (PDR), sessile serrated PDR, and advanced neoplasia detection rate were calculated for each group. Factors associated with adenoma detection were identified using a logistical regression analysis. A total of 1711 patients were included in the study (838 patients in the 170° group and 873 patients in the 140° group). ADR (43.79 vs 41.92%, P = .434) did not significantly differ between the 2 groups. The generational differences were not statistically significant either for PDR (56.44 vs 53.49%, P = .220), sessile serrated PDR (1.19 vs 0.92%, P = .575), or advanced neoplasia detection rate (5.00 vs 4.58%, P = .735). Multivariate regression analysis revealed that, age, male sex, and long withdrawal time were the most significant factors affecting adenoma detection. This study revealed that there were no differences in ADR while employing high definition colonoscopes with a 170° FOV and a 140° FOV.

Mucosal imaging in colon polyps: New advances and what the future may hold

An expanding range of advanced mucosal imaging technologies have been developed with the goal of improving the detection and characterization of lesions in the gastrointestinal tract. Many technologies have targeted colorectal neoplasia given the potential for intervention prior to the development of invasive cancer in the setting of widespread surveillance programs. Improvement in adenoma detection reduces miss rates and prevents interval cancer development. Advanced imaging technologies aim to enhance detection without significantly increasing procedural time. Accurate polyp characterisation guides resection techniques for larger polyps, as well as providing the platform for the “resect and discard” and “do not resect” strategies for small and diminutive polyps. This review aims to collate and summarise the evidence regarding these technologies to guide colonoscopic practice in both interventional and non-interventional endoscopists.

Updates in narrow-band imaging for colorectal polyps: Narrow-band imaging generations, detection, diagnosis, and artificial intelligence

Narrow-band imaging (NBI) is an optical digital enhancement method that allows the observation of vascular and surface structures of colorectal lesions. Its usefulness in the detection and diagnosis of colorectal polyps has been demonstrated in several clinical trials and the diagnostic algorithms have been simplified after the establishment of endoscopic classifications such as the Japan NBI Expert Team classification. However, there were issues including lack of brightness in the earlier models, poor visibility under insufficient bowel preparation, and the incompatibility of magnifying endoscopes in certain endoscopic platforms, which had impeded NBI from becoming standardized globally. Nonetheless, NBI continued its evolution and the newest endoscopic platform launched in 2020 offers significantly brighter and detailed images. Enhanced visualization is expected to improve the detection of polyps while universal compatibility across all scopes including magnifying endoscopy will promote the global standardization of magnifying diagnosis. Therefore, knowledge related to magnifying colonoscopy will become essential as magnification becomes standardly equipped in future models, although the advent of computer-aided diagnosis and detection may greatly assist endoscopists to ensure quality of practice. Given that most endoscopic departments will be using both old and new models, it is important to understand how each generation of endoscopic platforms differ from each other. We reviewed the advances in the endoscopic platforms, artificial intelligence, and evidence related to NBI essential for the next generation of endoscopic practice.

Colon mucosal injury caused by water jet malfunction during a screening colonoscopy: A case report

BACKGROUND

Screening colonoscopies are routinely performed and have low occurrences of adverse events such as perforation, bleeding, infection, and post-polypectomy syndrome. True device related adverse events are rarely reported in the literature.

CASE SUMMARY

We report a case of a 51-year-old patient without past medical history who presented for her first screening colonoscopy. The patient was thought to have friable mucosa in the cecum and oozed upon water irrigation during screening colonoscopy. It was later identified that the colonoscope used during the index procedure had malfunctioned and produced a pin-point water jet which damaged the colon mucosa of cecum. The maintenance service identified a piece of rubber fragment lodged in the instrument component at the tip of the scope, resulting in high pressure water jet. Repeat colonoscopy with a functioning colonoscope confirmed normal colon mucosa without friability.

CONCLUSION

This is the first report of mucosa injury from a colonoscope water jet malfunction. Endoscopists should recognize the potential for endoscopic malfunction.

Reduced detection rate of artificial intelligence in images obtained from untrained endoscope models and improvement using domain adaptation algorithm

A training dataset that is limited to a specific endoscope model can overfit artificial intelligence (AI) to its unique image characteristics. The performance of the AI may degrade in images of different endoscope model. The domain adaptation algorithm, i.e., the cycle-consistent adversarial network (cycleGAN), can transform the image characteristics into AI-friendly styles. We attempted to confirm the performance degradation of AIs in images of various endoscope models and aimed to improve them using cycleGAN transformation. Two AI models were developed from data of esophagogastroduodenoscopies collected retrospectively over 5 years: one for identifying the endoscope models, Olympus CV-260SL, CV-290 (Olympus, Tokyo, Japan), and PENTAX EPK-i (PENTAX Medical, Tokyo, Japan), and the other for recognizing the esophagogastric junction (EGJ). The AIs were trained using 45,683 standardized images from 1,498 cases and validated on 624 separate cases. Between the two endoscope manufacturers, there was a difference in image characteristics that could be distinguished without error by AI. The accuracy of the AI in recognizing gastroesophageal junction was >0.979 in the same endoscope-examined validation dataset as the training dataset. However, they deteriorated in datasets from different endoscopes. Cycle-consistent adversarial network can successfully convert image characteristics to ameliorate the AI performance. The improvements were statistically significant and greater in datasets from different endoscope manufacturers [original → AI-trained style, increased area under the receiver operating characteristic (ROC) curve, P-value: CV-260SL → CV-290, 0.0056, P = 0.0106; CV-260SL → EPK-i, 0.0182, P = 0.0158; CV-290 → CV-260SL, 0.0134, P < 0.0001; CV-290 → EPK-i, 0.0299, P = 0.0001; EPK-i → CV-260SL, 0.0215, P = 0.0024; and EPK-i → CV-290, 0.0616, P < 0.0001]. In conclusion, cycleGAN can transform the diverse image characteristics of endoscope models into an AI-trained style to improve the detection performance of AI.

A Hybrid Surgical Simulator for Interactive Endoscopic Training

Endoscopy serves as an indispensable minimally-invasive surgical procedure. Due to the limited view and non-intuitive operation of the instrument, the mastery of endoscopic manipulation requires deep medical knowledge as well as complex perception and motor skills of the surgeon. Intensive surgical training is required, and simulation-based training is of more and more importance over traditional animal- or cadaver-based approaches. Here, we developed a hybrid surgical simulator that consists of a realistic physical organ model and an artificial intelligence (AI)-driven cyber model. We built a physical model of the full urinary tract with soft materials and detailed blood vessel structures. Endourological procedures were performed to localize and treat renal calculi by a flexible endoscope. An AI algorithm detects the lesions automatically with high accuracy and provides quantitative feedback about an operator's endoscopic skills. The hybrid simulator system shows great potential as an interactive and personalized learning environment for endoscopic skills. Clinical Relevance- This work establishes a preliminary approach for realistic endoscopic training. The developed hybrid surgical simulator - with high-fidelity physical organ models and quantitative feedback - can deliver effective hands-on learning to surgeons to improve their endoscopic skills.

Does i-scan improve adenoma detection rate compared to high-definition colonoscopy? A systematic review and meta-analysis

Background and study aims  Recent studies evaluated the impact of i-scan in improving the adenoma detection rate (ADR) compared to high-definition (HD) colonoscopy. We aimed to systematically review and analyze the impact of this technique. Methods  A thorough search of the following databases was undertaken: PubMed/Medline, EMBASE, Cochrane and Web of Science. Full-text RCTs and cohort studies directly comparing i-scan and HD colonoscopy were deemed eligible for inclusion. Dichotomous outcomes were pooled and compared using random effects model and DerSimonian-Laird approach. For each outcome, relative risk (RR), 95 % confidence interval (CI), and P value was generated. P  < 0.05 was considered statistically significant. Results  A total of five studies with six arms were included in this analysis. A total of 2620 patients (mean age 58.6 ± 7.2 years and female proportion 44.8 %) completed the study and were included in our analysis. ADR was significantly higher with any i-scan (RR: 1.20, [CI: 1.06-1.34], P  = 0.003) compared to HD colonoscopy. Subgroup analysis demonstrated that ADR was significantly higher using i-scan with surface and contrast enhancement only (RR: 1.25, [CI: 1.07-1.47], P  = 0.004). Conclusions  i-scan has the potential to increase ADR using the surface and contrast enhancement method. Future studies evaluating other outcomes of interest such as proximal adenomas and serrated lesions are warranted.

Enhancing polyp detection: technological advances in colonoscopy imaging

The detection and removal of polyps at colonoscopy is core to the current colorectal cancer (CRC) prevention strategy. However, colonoscopy is flawed with a well described miss rate and variability in detection rates associated with incomplete protection from CRC. Consequently, there is significant interest in techniques and technologies which increase polyp detection with the aim to remedy colonoscopy's ills. Technologic advances in colonoscope imaging are numerous and include; increased definition of imaging, widening field of view, virtual technologies to supplant conventional chromocolonoscopy (CC) and now computer assisted detection. However, despite nearly two decades of technologic advances, data on gains in detection from individual technologies have been modest at best and heterogenous and conflicted as a rule. This state of detection technology science is exacerbated by use of relatively blunt metrics of improvement without consensus, the myopic search for gains over single generations of technology improvement and an unhealthy focus on adenomatous lesions. Yet there remains cause for optimism as detection gains from new technology, while small, may still improve CRC prevention. The technologies are also readily available in current generation colonoscopes and have roles beyond simply detection such as lesion characterization, further improving their worth. Coupled with the imminent expansion of computer assisted detection the detection future from colonoscope imaging advances looks bright. This review aims to cover the major imaging advances and evidence for improvement in polyp detection.

Advances in optical gastrointestinal endoscopy: a technical review

Optical endoscopy is the primary diagnostic and therapeutic tool for management of gastrointestinal (GI) malignancies. Most GI neoplasms arise from precancerous lesions; thus, technical innovations to improve detection and diagnosis of precancerous lesions and early cancers play a pivotal role in improving outcomes. Over the last few decades, the field of GI endoscopy has witnessed enormous and focused efforts to develop and translate accurate, user-friendly, and minimally invasive optical imaging modalities. From a technical point of view, a wide range of novel optical techniques is now available to probe different aspects of light-tissue interaction at macroscopic and microscopic scales, complementing white light endoscopy. Most of these new modalities have been successfully validated and translated to routine clinical practice. Herein, we provide a technical review of the current status of existing and promising new optical endoscopic imaging technologies for GI cancer screening and surveillance. We summarize the underlying principles of light-tissue interaction, the imaging performance at different scales, and highlight what is known about clinical applicability and effectiveness. Furthermore, we discuss recent discovery and translation of novel molecular probes that have shown promise to augment endoscopists' ability to diagnose GI lesions with high specificity. We also review and discuss the role and potential clinical integration of artificial intelligence-based algorithms to provide decision support in real time. Finally, we provide perspectives on future technology development and its potential to transform endoscopic GI cancer detection and diagnosis.

Endoscopic diagnosis and treatment of gastric dysplasia and early cancer: Current evidence and what the future may hold

Gastric cancer accounts for a significant proportion of worldwide cancer-related morbidity and mortality. The well documented precancerous cascade provides an opportunity for clinicians to detect and treat gastric cancers at an endoscopically curable stage. In high prevalence regions such as Japan and Korea, this has led to the implementation of population screening programs. However, guidelines remain ambiguous in lower prevalence regions. In recent years, there have been many advances in the endoscopic diagnosis and treatment of early gastric cancer and precancerous lesions. More advanced endoscopic imaging has led to improved detection and characterization of gastric lesions as well as superior accuracy for delineation of margins prior to resection. In addition, promising early data on artificial intelligence in gastroscopy suggests a future role for this technology in maximizing the yield of advanced endoscopic imaging. Data on endoscopic resection (ER) are particularly robust in Japan and Korea, with high rates of curative ER and markedly reduced procedural morbidity. However, there is a shortage of data in other regions to support the applicability of protocols from these high prevalence countries. Future advances in endoscopic therapeutics will likely lead to further expansion of the current indications for ER, as both technology and proceduralist expertise continue to grow.

Latest Generation High-Definition Colonoscopy Increases Adenoma Detection Rate by Trainee Endoscopists

BACKGROUND

Adenoma detection rate (ADR) is an important quality indicator of colonoscopy. High-definition (HD) colonoscopy has been reported to increase ADR compared to standard-definition (SD) colonoscopy. Although there are few reports comparing the latest generation and the previous generation of HD colonoscopy equipment, there are reports that the latest generation colonoscopy equipment improves ADR. However, there are no reports on the impact of the latest generation HD colonoscopy on the ADR of trainee endoscopists.

AIMS

The aim of this study was to investigate whether the latest generation HD colonoscopy increases the ADR of trainee endoscopists compared with the previous generation HD colonoscopy.

METHOD

We conducted a retrospective review of medical records of patients aged 40-79 years old, who underwent screening or surveillance colonoscopy performed by nine gastroenterology fellows at Dong-A University Hospital from March 2019 to February 2020. We calculated the overall ratios of the ADR: the ADRs of the group using the older generation HD colonoscopy equipment and the group using the latest HD colonoscopy equipment. Polyp detection rate (PDR), sessile serrated polyp detection rate (SSPDR), and advanced neoplasia detection rate (ANDR) were calculated for each group. Factors related to adenoma detection were identified using logistic regression analysis.

RESULTS

Altogether, 2189 patients were included in the study (the older HD colonoscopy group comprising 1183 and the latest HD colonoscopy group comprising 1006). We found that PDR (45.98 vs. 51.69%, p = 0.008) and ADR (35.67 vs. 40.85%, p = 0.013) were significantly higher in the latest generation HD colonoscopy group. The generational differences were not statistically significant for SSPDR (1.94 vs. 2.78%, p = 0.195) or ANDR (4.65 vs. 4.97%, p = 0.726). In the multivariate regression analysis, age, male sex, the latest generation HD colonoscopy, and long withdrawal time were the most significant factors affecting adenoma detection.

CONCLUSIONS

The latest generation HD colonoscopy improved PDR and ADR by trainee endoscopists. These findings suggest that latest generation, higher-resolution colonoscopy equipment can improve the quality of colonoscopy for less experienced endoscopists.

Standard vs magnifying narrow-band imaging endoscopy for diagnosis of Helicobacter pylori infection and gastric precancerous conditions

BACKGROUND

Advances in endoscopic imaging enable the identification of patients at high risk of gastric cancer. However, there are no comparative data on the utility of standard and magnifying narrow-band imaging (M-NBI) endoscopy for diagnosing Helicobacter pylori (H. pylori) infection, gastric atrophy, and intestinal metaplasia.

AIM

To compare the diagnostic performance of standard and M-NBI endoscopy for H. pylori gastritis and precancerous conditions.

METHODS

In 254 patients, standard endoscopy findings were classified into mosaic-like appearance (type A), diffuse homogenous redness (type B), and irregular redness with groove (type C). Gastric mucosal patterns visualized by M-NBI were classified as regular round pits with polygonal sulci (type Z-1), more dilated and linear pits without sulci (type Z-2), and loss of gastric pits with coiled vessels (type Z-3).

RESULTS

The diagnostic accuracy of standard and M-NBI endoscopy for H. pylori gastritis was 93.3% and 96.1%, respectively. Regarding gastric precancerous conditions, the accuracy of standard and M-NBI endoscopy was 72.0% vs 72.6% for moderate to severe atrophy, and 61.7% vs. 61.1% for intestinal metaplasia in the corpus, respectively. Compared to type A and Z-1, types B+C and Z-2+Z-3 were significantly associated with moderate to severe atrophy [odds ratio (OR) = 5.56 and 8.67] and serum pepsinogen I/II ratio of ≤ 3 (OR = 4.48 and 5.69).

CONCLUSION

Close observation of the gastric mucosa by standard and M-NBI endoscopy is useful for the diagnosis of H. pylori gastritis and precancerous conditions.

Clinically Available Optical Imaging Technologies in Endoscopic Lesion Detection: Current Status and Future Perspective

Endoscopic optical imaging technologies for the detection and evaluation of dysplasia and early cancer have made great strides in recent decades. With the capacity of in vivo early detection of subtle lesions, they allow modern endoscopists to provide accurate and effective optical diagnosis in real time. This review mainly analyzes the current status of clinically available endoscopic optical imaging techniques, with emphasis on the latest updates of existing techniques. We summarize current coverage of these technologies in major hospital departments such as gastroenterology, urology, gynecology, otolaryngology, pneumology, and laparoscopic surgery. In order to promote a broader understanding, we further cover the underlying principles of these technologies and analyze their performance. Moreover, we provide a brief overview of future perspectives in related technologies, such as computer-assisted diagnosis (CAD) algorithms dealing with exploring endoscopic video data. We believe all these efforts will benefit the healthcare of the community, help endoscopists improve the accuracy of diagnosis, and relieve patients' suffering.

Trends and Clinical Impact of Gastrointestinal Endoscopic Procedures on Acute Heart Failure in Spain (2002-2017)

Introduction: Heart failure decompensation can be triggered by many factors, including anemia. In cases of iron deficiency anemia or iron deficiency without anemia, endoscopic studies are recommended to rule out the presence of gastrointestinal neoplasms or other associated bleeding lesions. Objectives: The aims of this study were to (i) examine trends in the incidence, clinical characteristics, and in-hospital outcomes of patients hospitalized with heart failure from 2002 to 2017 who underwent esophagogastroduodenoscopy (EGD) and/or colonoscopy, and to (ii) identify factors associated with in-hospital mortality (IHM) among patients with heart failure who underwent an EGD and/or a colonoscopy. Methods: We conducted an observational retrospective epidemiological study using the Spanish National Hospital Discharge Database (SNHDD) between 2002 and 2017. We included hospitalizations of patients with a primary discharge diagnosis of heart failure. Cases were reviewed if there was an ICD-9-CM or ICD-10 procedure code for EGD or colonoscopy in any procedure field. Multivariable logistic regression models were constructed to identify predictors of IHM among HF patients who underwent an EGD or colonoscopy. Results: A total of 51,187 (1.32%) non-surgical patients hospitalized with heart failure underwent an EGD and another 72,076 (1.85%) patients had a colonoscopy during their admission. IHM was significantly higher in those who underwent an EGD than in those who underwent a red blood cell transfusion (OR 1.10; 95%CI 1.04–1.12). However, the use of colonoscopy seems to decrease the probability of IHM (OR 0.45; 95%CI 0.41–0.49). In patients who underwent a colonoscopy, older age seems to increase the probability of IHM. However, EGD was associated with a lower mortality (OR 0.60; 95% CI 0.55–0.64). Conclusion: In our study, a decrease in the number of gastroscopies was observed in relation to colonoscopy in patients with heart failure. The significant ageing of the hospitalized HF population seen over the course of the study could have contributed to this. Both procedures seemed to be associated with lower in-hospital mortality, but in the case of colonoscopy, the risk of in-hospital mortality was higher in elderly patients with heart failure and associated neoplasms. Colonoscopy and EGD seemed not to increase IHM in patients with heart failure.

Evaluation of Pelvic Anastomosis by Endoscopic and Contrast Studies Prior to Ileostomy Closure: Are Both Necessary? A Single Institution Review

Contrast enema is the gold standard technique for evaluating a pelvic anastomosis (PA) prior to ileostomy closure. With the increasing use of flexible endoscopic modalities, the need for contrast studies may be unnecessary. The objective of this study is to compare flexible endoscopy and contrast studies for anastomotic inspection prior to defunctioning stoma reversal. Patients with a protected PA undergoing ileostomy closure between July 2014 and June 2019 at our institution were retrospectively identified. Demographics and clinical outcomes in patients undergoing preoperative evaluation with endoscopic and/or contrast studies were analyzed. We identified 207 patients undergoing ileostomy closure. According to surgeon's preference, 91 patients underwent only flexible endoscopy (FE) and 100 patients underwent both endoscopic and contrast evaluation (FE + CE) prior to reversal. There was no significant difference in pelvic anastomotic leak (2.2% vs. 1%), anastomotic stricture (1.1% vs. 6%), pelvic abscess (2.2% vs. 3.0%), or postoperative anastomotic complications (4.4% vs. 9%) between groups FE and FE + CE (P > .05). Flexible endoscopy alone appears to be an acceptable technique for anastomotic evaluation prior to ileostomy closure. Further studies are needed to determine the effectiveness of different diagnostic modalities for pelvic anastomotic inspection.

State of the Science on Quality Indicators for Colonoscopy and How to Achieve Them

Colonoscopy is a safe and effective tool, but operator dependent. Room for improvement in the quality of colonoscopy is the impetus for the development and measurement of colonoscopy quality indicators and the focus of many efforts to improve colonoscopy quality indicator prevention and control in provider practices and health systems. We present the preprocedural, intraprocedural, and postprocedural quality indicators and benchmarks for colonoscopy. Every provider and practice must make a commitment to performing high-quality colonoscopy and implement and monitor quality metrics. There are a variety of tools available to assist in improving quality indicators that range from distal attachment devices to education and feedback. Although technology can help, it is not a substitute for proper technique. The commitment also requires provider feedback through audits and report cards. The impact of these efforts on patient outcomes is an important area of further research.

Narrow-band imaging and high-definition white-light endoscopy in patients with serrated lesions not fulfilling criteria for serrated polyposis syndrome: a randomized controlled trial with tandem colonoscopy

BACKGROUND

It is unknown whether narrow-band imaging (NBI) could be more effective than high-definition white-light endoscopy (HD-WLE) in detecting serrated lesions in patients with prior serrated lesions > 5 mm not completely fulfilling serrated polyposis syndrome (SPS) criteria.

METHODS

We conducted a randomized, cross-over trial in consecutive patients with prior detection of at least one serrated polyp ≥10 mm or ≥ 3 serrated polyps larger than 5 mm, both proximal to the sigmoid colon. Five experienced endoscopists performed same-day tandem colonoscopies, with the order being randomized 1:1 to NBI-HD-WLE or HD-WLE-NBI. All tandem colonoscopies were performed by the same endoscopist.

RESULTS

We included 41 patients. Baseline characteristics were similar in the two cohorts: NBI-HD-WLE (n = 21) and HD-WLE-NBI (n = 20). No differences were observed in the serrated lesion detection rate of NBI versus HD-WLE: 47.4% versus 51.9% (OR 0.84, 95% CI: 0.37-1.91) for the first and second withdrawal, respectively. Equally, no differences were found in the polyp miss rate of NBI versus HD-WLE: 21.3% versus 26.1% (OR 0.77, 95% CI: 0.43-1.38). Follow-up colonoscopy in nine patients (22%) allowed them to be reclassified as having SPS.

CONCLUSIONS

In patients with previous serrated lesions, the serrated lesion detection rate was similar with NBI and HD-WLE. A shorter surveillance colonoscopy interval increases the detection of missed serrated polyps and could change the diagnosis of SPS in approximately one in every five patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02406547, registered on April 2, 2015.

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.

Advanced endoscopy technologies to improve the detection and characterisation of colorrectal polyps

Colorectal cancer is a major health problem. An improvement to its survival has been demonstrated by performing colonoscopy screenings and removing its precursor lesions: polyps. However, colonoscopy is not infallible and multiple strategies have been proposed aimed at improving the quality thereof. This report describes the endoscopic systems available to improve the detection and characterization of polyps, the different classifications for histological prediction and the current indications of advanced endoscopic diagnostic techniques.

Submillimeter diameter rotary-pullback fiber-optic endoscope for narrowband red-green-blue reflectance, optical coherence tomography, and autofluorescence in vivo imaging

A fiber-based endoscopic imaging system combining narrowband red-green-blue (RGB) reflectance with optical coherence tomography (OCT) and autofluorescence imaging (AFI) has been developed. The system uses a submillimeter diameter rotary-pullback double-clad fiber imaging catheter for sample illumination and detection. The imaging capabilities of each modality are presented and demonstrated with images of a multicolored card, fingerprints, and tongue mucosa. Broadband imaging, which was done to compare with narrowband sources, revealed better contrast but worse color consistency compared with narrowband RGB reflectance. The measured resolution of the endoscopic system is 25  μm in both the rotary direction and the pullback direction. OCT can be performed simultaneously with either narrowband RGB reflectance imaging or AFI.

Colorectal cancer surveillance in inflammatory bowel disease: Practice guidelines and recent developments

Patients with long-standing inflammatory bowel disease (IBD) involving at least 1/3 of the colon are at increased risk for colorectal cancer (CRC). Advancements in CRC screening and surveillance and improved treatment of IBD has reduced CRC incidence in patients with ulcerative colitis and Crohn’s colitis. Most cases of CRC are thought to arise from dysplasia, and recent evidence suggests that the majority of dysplastic lesions in patients with IBD are visible, in part thanks to advancements in high definition colonoscopy and chromoendoscopy. Recent practice guidelines have supported the use of chromoendoscopy with targeted biopsies of visible lesions rather than traditional random biopsies. Endoscopists are encouraged to endoscopically resect visible dysplasia and only recommend surgery when a complete resection is not possible. New technologies such as virtual chromoendoscopy are emerging as potential tools in CRC screening. Patients with IBD at increased risk for developing CRC should undergo surveillance colonoscopy using new approaches and techniques.

Meta-analysis of dye-based chromoendoscopy compared with standard- and high-definition white-light endoscopy in patients with inflammatory bowel disease at increased risk of colon cancer

BACKGROUND

Patients with ulcerative colitis have an increased risk of colorectal cancer. We sought to assess the comparative efficacy of standard white-light endoscopy (SDWLE) or high-definition white-light endoscopy (HDWLE) versus dye-based chromoendoscopy through a meta-analysis and rate the quality of evidence using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) system.

METHODS

A systematic review of the literature in PubMed, EMBASE, and Web of Science was performed in April 2018. The primary outcome was the number of patients in whom dysplasia was identified using a per patient analysis in randomized controlled trials (RCT) and analyzed separately for non-RCTs. Analysis was performed using RevMan 5.3 reporting random-effects risk ratios.

RESULTS

Of the 27,904 studies identified, 10 studies were included 6 of which were RCTs (3 SDWLE and 3 HDWLE). Seventeen percent (84/494) of patients were noted to have dysplasia using chromoendoscopy compared with 11% (55/496) with white-light endoscopy (relative risk [RR] 1.50; 95% confidence interval [CI], 1.08-2.10). When analyzed separately, chromoendoscopy (n = 249) was more effective at identifying dysplasia than SDWLE (n = 248) (RR, 2.12; 95% CI, 1.15-3.91), but chromoendoscopy (n = 245) was not more effective compared with HDWLE (n = 248) (RR, 1.36; 95% CI, 0.84-2.18). The quality of evidence was moderate. In non-RCTs, dysplasia was identified in 16% (114/698) of patients with chromoendoscopy compared with 6% (62/1069) with white-light endoscopy (RR, 3.41; 95% CI, 2.13-5.47). Chromoendoscopy (n = 58) was more effective than SDWLE (n = 141) for identification of dysplasia (RR, 3.52; 95% CI, 1.38-8.99), and chromoendoscopy (n = 113) was also more effective than HDWLE (n = 257) (RR, 3.15; 95% CI, 1.62-6.13). The quality of the evidence was very low.

CONCLUSION

Based on this meta-analysis, non-RCTs demonstrate a benefit of chromoendoscopy over SDWLE and HDWLE, whereas RCTs only show a small benefit of chromoendoscopy over SDWLE, but not over HDWLE.

A roadmap for the clinical implementation of optical-imaging biomarkers

Clinical workflows for the non-invasive detection and characterization of disease states could benefit from optical-imaging biomarkers. In this Perspective, we discuss opportunities and challenges towards the clinical implementation of optical-imaging biomarkers for the early detection of cancer by analysing two case studies: the assessment of skin lesions in primary care, and the surveillance of patients with Barrett's oesophagus in specialist care. We stress the importance of technical and biological validations and clinical-utility assessments, and the need to address implementation bottlenecks. In addition, we define a translational roadmap for the widespread clinical implementation of optical-imaging technologies.

Systematic review with meta-analysis: Chromoendoscopy versus white light endoscopy in detection of dysplasia in patients with inflammatory bowel disease

OBJECTIVE

To compare chromoendoscopy (CE) and white light endoscopy (WLE) for dysplasia surveillance in patients with inflammatory bowel disease (IBD).

METHODS

We conducted a meta-analysis of 6 randomized controlled trials (RCTs) and 5 prospective studies and compared the CE and WLE groups. A fixed-effect model was used unless the heterogeneity was high.

RESULTS

CE detected more patients with dysplasia (relative risk [RR] 2.05, 95% confidence interval [CI]: 1.62-2.61) and more dysplastic lesions (RR 2.04, 95% CI: 1.40-2.98) than WLE. When magnification was added to CE, the detection rate of patients with dysplasia and dysplastic lesions improved. CE also detected more patients with dysplasia than high-definition WLE (RR 1.60, 95% CI: 1.11-2.29). Compared with WLE, the incremental yield of CE for detecting patients with dysplasia was 9%. CE was superior to WLE in detecting non-polypoid dysplastic lesions (RR 1.38, 95% CI:1.02-1.88). CE had no advantage for detecting polypoid dysplastic lesions compared with WLE.

CONCLUSIONS

CE is superior to WLE in the surveillance of dysplasia in IBD patients. It is thus necessary to use CE in the surveillance of dysplasia in patients with IBD in clinical practice. Adding magnification improves the detection rate.

Quest for the best endoscopic imaging modality for computer-assisted colonic polyp staging

BACKGROUND

It was shown in previous studies that high definition endoscopy, high magnification endoscopy and image enhancement technologies, such as chromoendoscopy and digital chromoendoscopy [narrow-band imaging (NBI), i-Scan] facilitate the detection and classification of colonic polyps during endoscopic sessions. However, there are no comprehensive studies so far that analyze which endoscopic imaging modalities facilitate the automated classification of colonic polyps. In this work, we investigate the impact of endoscopic imaging modalities on the results of computer-assisted diagnosis systems for colonic polyp staging.

AIM

To assess which endoscopic imaging modalities are best suited for the computer-assisted staging of colonic polyps.

METHODS

In our experiments, we apply twelve state-of-the-art feature extraction methods for the classification of colonic polyps to five endoscopic image databases of colonic lesions. For this purpose, we employ a specifically designed experimental setup to avoid biases in the outcomes caused by differing numbers of images per image database. The image databases were obtained using different imaging modalities. Two databases were obtained by high-definition endoscopy in combination with i-Scan technology (one with chromoendoscopy and one without chromoendoscopy). Three databases were obtained by high-magnification endoscopy (two databases using narrow band imaging and one using chromoendoscopy). The lesions are categorized into non-neoplastic and neoplastic according to the histological diagnosis.

RESULTS

Generally, it is feature-dependent which imaging modalities achieve high results and which do not. For the high-definition image databases, we achieved overall classification rates of up to 79.2% with chromoendoscopy and 88.9% without chromoendoscopy. In the case of the database obtained by high-magnification chromoendoscopy, the classification rates were up to 81.4%. For the combination of high-magnification endoscopy with NBI, results of up to 97.4% for one database and up to 84% for the other were achieved. Non-neoplastic lesions were classified more accurately in general than non-neoplastic lesions. It was shown that the image recording conditions highly affect the performance of automated diagnosis systems and partly contribute to a stronger effect on the staging results than the used imaging modality.

CONCLUSION

Chromoendoscopy has a negative impact on the results of the methods. NBI is better suited than chromoendoscopy. High-definition and high-magnification endoscopy are equally suited.

Virtual chromoendoscopy for the real-time assessment of colorectal polyps in vivo: a systematic review and economic evaluation

BACKGROUND

Current clinical practice is to remove a colorectal polyp detected during colonoscopy and determine whether it is an adenoma or hyperplastic by histopathology. Identifying adenomas is important because they may eventually become cancerous if untreated, whereas hyperplastic polyps do not usually develop into cancer, and a surveillance interval is set based on the number and size of adenomas found. Virtual chromoendoscopy (VCE) (an electronic endoscopic imaging technique) could be used by the endoscopist under strictly controlled conditions for real-time optical diagnosis of diminutive (≤ 5 mm) colorectal polyps to replace histopathological diagnosis.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of the VCE technologies narrow-band imaging (NBI), flexible spectral imaging colour enhancement (FICE) and i-scan for the characterisation and management of diminutive (≤ 5 mm) colorectal polyps using high-definition (HD) systems without magnification.

DESIGN

Systematic review and economic analysis.

PARTICIPANTS

People undergoing colonoscopy for screening or surveillance or to investigate symptoms suggestive of colorectal cancer.

INTERVENTIONS

NBI, FICE and i-scan.

MAIN OUTCOME MEASURES

Diagnostic accuracy, recommended surveillance intervals, health-related quality of life (HRQoL), adverse effects, incidence of colorectal cancer, mortality and cost-effectiveness of VCE compared with histopathology.

DATA SOURCES

Electronic bibliographic databases including MEDLINE, EMBASE, The Cochrane Library and Database of Abstracts of Reviews of Effects were searched for published English-language studies from inception to June 2016. Bibliographies of related papers, systematic reviews and company information were screened and experts were contacted to identify additional evidence.

REVIEW METHODS

Systematic reviews of test accuracy and economic evaluations were undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Meta-analyses were conducted, where possible, to inform the independent economic model. A cost-utility decision-analytic model was developed to estimate the cost-effectiveness of VCE compared with histopathology. The model used a decision tree for patients undergoing endoscopy, combined with estimates of long-term outcomes (e.g. incidence of colorectal cancer and subsequent morbidity and mortality) derived from University of Sheffield School of Health and Related Research's bowel cancer screening model. The model took a NHS perspective, with costs and benefits discounted at 3.5% over a lifetime horizon. There were limitations in the data on the distribution of adenomas across risk categories and recurrence rates post polypectomy.

RESULTS

Thirty test accuracy studies were included: 24 for NBI, five for i-scan and three for FICE (two studies assessed two interventions). Polyp assessments made with high confidence were associated with higher sensitivity and endoscopists experienced in VCE achieved better results than those without experience. Two economic evaluations were included. NBI, i-scan and FICE are cost-saving strategies compared with histopathology and the number of quality-adjusted life-years gained was similar for histopathology and VCE. The correct surveillance interval would be given to 95% of patients with NBI, 94% of patients with FICE and 97% of patients with i-scan.

LIMITATIONS

Limited evidence was available for i-scan and FICE and there was heterogeneity among the NBI studies. There is a lack of data on longer-term health outcomes of patients undergoing VCE for assessment of diminutive colorectal polyps.

CONCLUSIONS

VCE technologies, using HD systems without magnification, could potentially be used for the real-time assessment of diminutive colorectal polyps, if endoscopists have adequate experience and training.

FUTURE WORK

Future research priorities include head-to-head randomised controlled trials of all three VCE technologies; more research on the diagnostic accuracy of FICE and i-scan (when used without magnification); further studies evaluating the impact of endoscopist experience and training on outcomes; studies measuring adverse effects, HRQoL and anxiety; and longitudinal data on colorectal cancer incidence, HRQoL and mortality.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016037767.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Accuracy of the Narrow-Band Imaging International Colorectal Endoscopic Classification System in Identification of Deep Invasion in Colorectal Polyps

BACKGROUND & AIMS

T1 colorectal polyps with at least 1 risk factor for metastasis to lymph node should be treated surgically and are considered endoscopically unresectable. Optical analysis, based on the Narrow-Band Imaging International Colorectal Endoscopic (NICE) classification system, is used to identify neoplasias with invasion of the submucosa that require endoscopic treatment. We assessed the accuracy of the NICE classification, along with other morphologic characteristics, in identifying invasive polyps that are endoscopically unresectable (have at least 1 risk factor for metastasis to lymph node).

METHODS

We performed a multicenter, prospective study of data collected by 58 endoscopists, from 1634 consecutive patients (examining 2123 lesions) at 17 university and community hospitals in Spain from July 2014 through June 2016. All consecutive lesions >10 mm assessed with narrow-band imaging were included. The primary end point was the accuracy of the NICE classification for identifying lesions with deep invasion, using findings from histology analysis as the reference standard. Conditional inference trees were fitted for the analysis of diagnostic accuracy.

RESULTS

Of the 2123 lesions analyzed, 89 (4.2%) had features of deep invasion and 91 (4.3%) were endoscopically unresectable. The NICE classification system identified lesions with deep invasion with 58.4% sensitivity (95% CI, 47.5-68.8), 96.4% specificity (95% CI, 95.5-97.2), a positive-predictive value of 41.6% (95% CI, 32.9-50.8), and a negative-predictive value of 98.1% (95% CI, 97.5-98.7). A conditional inference tree that included all variables found the NICE classification to most accurately identify lesions with deep invasion (P < .001). However, pedunculated morphology (P < .007), ulceration (P = .026), depressed areas (P < .001), or nodular mixed type (P < .001) affected accuracy of identification. Results were comparable for identifying lesions that were endoscopically unresectable.

CONCLUSIONS

In an analysis of 2123 colon lesions >10 mm, we found the NICE classification and morphologic features identify those with deep lesions with >96% specificity-even in non-expert hands and without magnification. ClinicalTrials.gov number NCT02328066.

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.

A comparison study between Magniview and high definition white light endoscopy in detecting villous atrophy and coeliac disease: A single centre pilot study

BACKGROUND AND AIMS

Coeliac disease may be missed at gastroscopy. We aimed to assess the sensitivity of Pentax optical zoom technology endoscopes in detecting duodenal villous atrophy and the ease of image interpretation by non-coeliac specialists.

METHOD

All patients attending for a gastroscopy were assessed for endoscopic villous atrophy in part one and two of the duodenum with high definition white light endoscopy and magnification endoscopy. Endoscopic findings of the duodenum were compared to histology as the reference standard. A short training video of varying degrees of villous atrophy seen by magnification endoscopy was used to train individuals. They were then assessed for the ability to differentiate between normal duodenum and villous atrophy.

RESULTS

Two hundred and fifty patients were prospectively recruited (145 females, 58%; age range 16-84, median age 50.5). Ninety-six patients had villous atrophy on histology (38.4%) 154 were controls. Magnification endoscopy had a higher sensitivity in detecting villous atrophy compared to high definition white light endoscopy (86.4% versus 78.4%, p = .0005). 9/10 individuals undertaking magnification endoscopy training correctly identified all cases of villous atrophy.

CONCLUSION

Magnification endoscopy has superior diagnostic sensitivity in detecting villous atrophy compared to high definition white light endoscopy and the potential to be easily adopted by all endoscopists.

Narrow-Band Imaging: Clinical Application in Gastrointestinal Endoscopy

Narrow-band imaging is an advanced imaging system that applies optic digital methods to enhance endoscopic images and improves visualization of the mucosal surface architecture and microvascular pattern. Narrow-band imaging use has been suggested to be an important adjunctive tool to white-light endoscopy to improve the detection of lesions in the digestive tract. Importantly, it also allows the distinction between benign and malignant lesions, targeting biopsies, prediction of the risk of invasive cancer, delimitation of resection margins, and identification of residual neoplasia in a scar. Thus, in expert hands it is a useful tool that enables the physician to decide on the best treatment (endoscopic or surgical) and management. Current evidence suggests that it should be used routinely for patients at increased risk for digestive neoplastic lesions and could become the standard of care in the near future, at least in referral centers. However, adequate training programs to promote the implementation of narrow-band imaging in daily clinical practice are needed. In this review, we summarize the current scientific evidence on the clinical usefulness of narrow-band imaging in the diagnosis and characterization of digestive tract lesions/cancers and describe the available classification systems.

Adenoma recurrence after endoscopic mucosal resection: propensity score analysis of old and new colonoscopes and Sydney recurrence tool implementation

BACKGROUND AND STUDY AIMS

 Risk factors for colorectal adenoma recurrence after endoscopic mucosal resection (EMR) have been well documented. We assessed the efficacy of the newer 190 colonoscope versus the standard 180 colonoscope for complete resection of lateral spreading lesions.

PATIENTS AND METHODS

 A single-center, retrospective study of patients who underwent EMR with Olympus 180 or 190 colonoscopes from January 1, 2010 to September 30, 2016. We included patients with lesions ≥ 20 mm and surveillance colonoscopy (SC1) after index EMR. A propensity score approach with inverse probability weighting was used to control for potential confounders. A secondary aim was to identify risk factors for recurrence and assess the applicability of the Sydney EMR recurrence tool (SERT) by grading each lesion of our cohort and analyzing associations with recurrence.

RESULTS

 Two hundred ninety-one lesions met inclusion criteria for the study. Odds ratio (OR) for recurrence with the 190 colonoscope was 1.06 ( P  = .85). Adenoma size ( P  = .02) and use of argon plasma coagulation (APC; P  < .001) were risk factors for recurrence. Lesions with SERT scores > 0 had a higher recurrence risk during follow-up (32 % vs 21 %; OR 1.71; P  = .05). Lesions with SERT scores = 0 reached a plateau for recurrence at 12 and 18 months in Kaplan-Meier curves.

CONCLUSIONS

 The use of 190 colonoscopes did not measurably affect adenoma recurrence at SC1. Recurrence was associated with adenoma size, complementary APC for resection, and SERT scores > 0. Lesions with SERT scores = 0 that remain negative for recurrence at 18 months may return to routine surveillance.

Multispectral light scattering endoscopic imaging of esophageal precancer

Esophageal adenocarcinoma is the most rapidly growing cancer in America. Although the prognosis after diagnosis is unfavorable, the chance of a successful outcome increases tremendously if detected early while the lesion is still dysplastic. Unfortunately, the present standard-of-care, endoscopic surveillance, has major limitations, since dysplasia is invisible, often focal, and systematic biopsies typically sample less than one percent of the esophageal lining and therefore easily miss malignancies. To solve this problem we developed a multispectral light scattering endoscopic imaging system. It surveys the entire esophageal lining and accurately detects subcellular dysplastic changes. The system combines light scattering spectroscopy, which detects and identifies invisible dysplastic sites by analyzing light scattered from epithelial cells, with rapid scanning of the entire esophageal lining using a collimated broadband light beam delivered by an endoscopically compatible fiber optic probe. Here we report the results of the first comprehensive multispectral imaging study, conducted as part of routine endoscopic procedures performed on patients with suspected dysplasia. In a double-blind study that characterized the system's ability to serve as a screening tool, 55 out of 57 patients were diagnosed correctly. In addition, a smaller double-blind comparison of the multispectral data in 24 patients with subsequent pathology at locations where 411 biopsies were collected yielded an accuracy of 90% in detecting individual locations of dysplasia, demonstrating the capability of this method to serve as a guide for biopsy.

Endoscopic Therapeutic Approach for Dysplasia in Inflammatory Bowel Disease

Long-standing intestinal inflammation in patients with inflammatory bowel disease (IBD) induces dysplastic change in the intestinal mucosa and increases the risk of subsequent colorectal cancer. The evolving endoscopic techniques and technologies, including dye spraying methods and high-definition images, have been replacing random biopsies and have been revealed as more practical and efficient for detection of dysplasia in IBD patients. In addition, they have potential usefulness in detailed characterization of lesions and in the assessment of endoscopic resectability. Most dysplastic lesions without an unclear margin, definite ulceration, non-lifting sign, and high index of malignant change with suspicion for lymph node or distant metastases can be removed endoscopically. However, endoscopic resection of dysplasia in chronic IBD patients is usually difficult because it is often complicated by submucosal fibrosis. In patients with dysplasias that demonstrate submucosa fibrosis or a large size (≥20 mm), endoscopic submucosal dissection (ESD) or ESD with snaring (simplified or hybrid ESD) is an alternative option and may avoid a colectomy. However, a standardized endoscopic therapeutic approach for dysplasia in IBD has not been established yet, and dedicated specialized endoscopists with interest in IBD are needed to fully investigate recent emerging techniques and technologies.

Ultra-compact optical zoom endoscope using solid tunable lenses

We report an ultra-compact optical zoom endoscope containing two tunable Alvarez lenses. The two tunable lenses are controlled synchronously by piezoelectric benders to move in directions perpendicular to the optical axis to achieve optical zoom while keeping images in clear focus without moving the scope. The piezoelectric benders are arranged circumferentially surrounding the endoscope optics with a diameter about 2 mm, which results in an ultra-compact form. The demonstrated endoscope is capable of optical zoom close to 3 × from field of view (FOV) 50° to 18° continuously with the required movements for its constituent optical elements less than 110 μm. Such optical zoom endoscopes may find their potential uses in healthcare and industrial inspection systems.

Colorectal endoscopic submucosal dissection (ESD)

Endoscopic submucosal dissection (ESD) is an interventional procedure for en-bloc resection of gastrointestinal lesions. ESD is a challenging and can involve a reasonable degree of risk, therefore case selection is of crucial importance, especially in the colo-rectum. This procedure should be mainly used for dissection of lesions when there is a high suspicion of superficial malignant invasion; several classifications have been proposed in order to better identify lesions suitable for ESD. However, case selection is still an issue, since only about 8-10% of dissected lesions are superficially invading cancer and most of cases involve benign or massively invading cancer. In addition, significant differences have been reported between Asian and Western countries in regard to main outcomes, and therefore measures should be adopted as soon as possible to reduce this discrepancy.

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.

A guide to multimodal endoscopy imaging for gastrointestinal malignancy - an early indicator

Multimodality imaging is an essential aspect of endoscopic surveillance for the detection of neoplastic lesions, such as dysplasia or intramucosal cancer, because it improves the efficacy of endoscopic surveillance and therapeutic procedures in the gastrointestinal tract. This approach reveals mucosal abnormalities that cannot be detected by standard endoscopy. Currently, these imaging techniques are divided into those for primary detection and those for targeted imaging and characterization, the latter being used to visualize areas of interest in detail and permit histological evaluation. This Review outlines the use of virtual chromoendoscopy, narrow-band imaging, autofluorescence imaging, optical coherence tomography, confocal endomicroscopy and volumetric laser endomicroscopy as new imaging techniques for diagnostic investigation of the gastrointestinal tract. Insights into use of multimodal endoscopic imaging for early disease detection, in particular for pre-malignant lesions, in the oesophagus, stomach and colon are described.

Endoscope field of view measurement

The current International Organization for Standardization (ISO) standard (ISO 8600-3: 1997 including Amendment 1: 2003) for determining endoscope field of view (FOV) does not accurately characterize some novel endoscopic technologies such as endoscopes with a close focus distance and capsule endoscopes. We evaluated the endoscope FOV measurement method (the FOV_WS method) in the current ISO 8600-3 standard and proposed a new method (the FOV_EP method). We compared the two methods by measuring the FOV of 18 models of endoscopes (one device for each model) from seven key international manufacturers. We also estimated the device to device variation of two models of colonoscopes by measuring several hundreds of devices. Our results showed that the FOV_EP method was more accurate than the FOV_WS method, and could be used for all endoscopes. We also found that the labelled FOV values of many commercial endoscopes are significantly overstated. Our study can help endoscope users understand endoscope FOV and identify a proper method for FOV measurement. This paper can be used as a reference to revise the current endoscope FOV measurement standard.

Advanced imaging in colonoscopy: contemporary approach to dysplasia surveillance in inflammatory bowel disease

Inflammatory bowel disease (IBD) (ulcerative colitis (UC) and Crohn's disease (CD)) is a chronic relapsing/remitting condition characterised by intestinal inflammation. One of the main concerns in patients with longstanding ulcerative and Crohn's colitis is development of colonic dysplasia and colorectal cancer (CRC), a risk higher than that of the general population. Colonoscopy surveillance programmes have been developed by major societies worldwide to improve early dysplasia detection and treatment, thus preventing progression to colorectal cancer. Colonoscopy is an imperfect tool as lesions can be missed, an issue even more relevant to colitic patients, where mucosal inspection and lesion recognition may prove challenging. Extensive research has been undertaken on performance improvement in this area while technical advances in optical imaging, such as high-definition, have made their way into modern endoscopy units. Techniques and technologies available to enhance optical diagnosis of dysplasia in inflammatory bowel disease are reviewed in this paper, focusing on those that are realistic, widely available and feasible for everyday practice.