Endoscopic innovations to increase the adenoma detection rate during colonoscopy

Up to a quarter of polyps and adenomas are missed during colonoscopy due to poor visualization behind folds and the inner curves of flexures, and the presence of flat lesions that are difficult to detect. These numbers may however be conservative because they mainly come from back-to-back studies performed with standard colonoscopes, which are unable to visualize the entire mucosal surface. In the past several years, new endoscopic techniques have been introduced to improve the detection of polyps and adenomas. The introduction of high definition colonoscopes and visual image enhancement technologies have been suggested to lead to better recognition of flat and small lesions, but the absolute increase in diagnostic yield seems limited. Cap assisted colonoscopy and water-exchange colonoscopy are methods to facilitate cecal intubation and increase patients comfort, but show only a marginal or no benefit on polyp and adenoma detection. Retroflexion is routinely used in the rectum for the inspection of the dentate line, but withdrawal in retroflexion in the colon is in general not recommended due to the risk of perforation. In contrast, colonoscopy with the Third-Eye Retroscope® may result in considerable lower miss rates compared to standard colonoscopy, but this technique is not practical in case of polypectomy and is more time consuming. The recently introduced Full Spectrum Endoscopy™ colonoscopes maintains the technical capabilities of standard colonoscopes and provides a much wider view of 330 degrees compared to the 170 degrees with standard colonoscopes. Remarkable lower adenoma miss rates with this new technique were recently demonstrated in the first randomized study. Nonetheless, more studies are required to determine the exact additional diagnostic yield in clinical practice. Optimizing the efficacy of colorectal cancer screening and surveillance requires high definition colonoscopes with improved virtual chromoendoscopy technology that visualize the whole colon mucosa while maintaining optimal washing, suction and therapeutic capabilities, and keeping the procedural time as low and patient discomfort as optimal as possible.

Polyp detection rate and pathological features in patients undergoing a comprehensive colonoscopy screening

AIMTo identify the prevalence, and clinical and pathologic characteristic of colonic polyps among Iranian patients undergoing a comprehensive colonoscopy, and determine the polyp detection rate (PDR) and adenoma detection rate (ADR). METHODSIn this cross-sectional study, demographics and epidemiologic characteristics of 531 persons who underwent colonoscopies between 2014 and 2015 at Mehrad gastrointestinal clinic were determined. Demographics, indication for colonoscopy, colonoscopy findings, number of polyps, and histopathological characteristics of the polyps were examined for each person. RESULTSOur sample included 295 (55.6%) women and 236 (44.4%) men, with a mean age of 50.25 ± 14.89 years. Overall PDR was 23.5% (125/531). ADR and colorectal cancer detection rate in this study were 12.8% and 1.5%, respectively. Polyps were detected more significantly frequently in men than in women (52.8% vs 47.2%, P vs 56.4 years, P CONCLUSIONThe prevalence of polyps and adenomas in this study is less than that reported in the Western populations. In our patients, distal colon is more susceptible to developing polyps and cancer than proximal colon.

Does hyoscine butylbromide really improve polyp detection during colonoscopy? A meta-analysis of randomized controlled trials

AIM: To investigate the benefits of hyoscine butylbromide in polyp detection during colonoscopy by a meta-analysis of available randomized controlled trials (RCTs).

Colonoscopy procedural volume increases adenoma and polyp detection rates in gastroenterology trainees

AIM To investigate changes in polyp detection throughout fellowship training, and estimate colonoscopy volume required to achieve the adenoma detection rate(ADRs) and polyp detection rate(PDRs) of attending gastroenterologists.METHODS We reviewed colonoscopies from July 1, 2009 to June 30, 2014. Fellows' procedural logs were used to retrieve colonoscopy procedural volumes, and these were treated as the time variable. Findings from screening colonoscopies were used to calculate colonoscopy outcomes for each fellow for the prior 50 colonoscopies at each time point. ADR and PDR were plotted against colonoscopy procedural volumes to produce individual longitudinal graphs. Repeated measures linear mixed effects models were used to study the change of ADR and PDR with increasing procedural volume.RESULTS During the study period, 12 fellows completed full three years of training and were included in the analysis. The average ADR and PDR were, respectively, 31.5% and 41.9% for all fellows, and 28.9% and 38.2% for attendings alone. There was a statistically significant increase in ADR with increasing procedural volume(1.8%/100 colonoscopies, P = 0.002). Similarly, PDR increased 2.8%/100 colonoscopies(P = 0.0001), while there was no significant change in advanced ADR(0.04%/100 colonoscopies, P = 0.92). The ADR increase was limited to the right side of the colon, while the PDR increased in both the right and left colon. The adenoma per colon and polyp per colon also increased throughout training. Fellows reached the attendings' ADR and PDR after 265 and 292 colonoscopies, respectively.CONCLUSION We found that the ADR and PDR increase with increasing colonoscopy volume throughout fellowship. Our findings support recent recommendations of ≥ 275 colonoscopies for colonoscopy credentialing.

High resolution colonoscopy in a bowel cancer screening program improves polyp detection

AIM： To compare high resolution colonoscopy （Olympus Lucera） with a megapixel high resolution system （Pentax HiLine） as an in-service evaluation. METHODS： Polyp detection rates and measures of performance were collected for 269 colonoscopy procedures. Five colonoscopists conducted the study over a three month period, as part of the United Kingdom bowel cancer screening program. RESULTS：There were no differences in procedure duration （x^2 p = 0.98）, caecal intubation rates （x^2 P = 0.67）, or depth of sedation （x^2 P = 0.64）. Mild discomfort was more common in the Pentax group （x^2 p = 0.036）. Adenoma detection rate was significantly higher in the Pentax group （x^2 test for trend P = 0.01）. Most of the extra polyps detected were flat or sessile adenomas. CONCLUSION： Megapixel definition colonoscopes improve adenoma detection without compromising other measures of endoscope performance. Increased polyp detection rates may improve future outcomes in bowel cancer screening programs.

A Polyp Detection Method Based on FBnet

The incidence of colorectal cancer(CRC)in China has increased in recent years.The mortality rate of CRC has become one of the highest among all cancers;CRC increasingly affects the health and quality of people’s lives.However,due to the insufficiency of medical resources in China,the workload on medical doctors has further increased.In the past few decades,the adult CRC mortality and morbidity rate dropped sharply,mainly because of CRC screening and removal of adenomatous polyps.However,due to the differences in polyp itself and the skills of endoscopists,the detection rate of polyps varies greatly.In this paper,we adopt an anchor-free mechanism and introduce a better method to factorize the process of bounding box regression.Firstly,we regress the shape of object by the variant of Faster RCNN.Secondly,we re-define the target function of the location of object.The experimental result shows that our method achieves a mAP of 55.8%,which outperforms other state-of-the-art methods by at least 11.9%.This will greatly help to reduce the missed diagnosis of clinicians during endoscopy and treatment,and provide effective help for early diagnosis,early treatment and prevention of CRC.

Diagnostic yield of third eye retroscope on adenoma detection during colonoscopy:A systematic review and meta-analysis

AIM： To determine the diagnostic yield of the “third eye retroscope”, on adenoma detection rate during screening colonoscopy.METHODS： The “third eye retroscope” when used with standard colonoscopy provides an additional retro-grade view to visualize lesions on the proximal aspects of folds and fexures. We searched MEDLINE （PubMed and Ovid）, SCOPUS （including MEDLINE and EMBASE databases）, Cochrane Database of Systemic Reviews, Google Scholar, and CINAHL Plus databases to identify studies that evaluated diagnostic yield of “third eye retroscope” during screening colonoscopy. DerSimonian Laird random effects model was used to generate the overall effect for each outcome. We evaluated statistical heterogeneity among the studies by using the Cochran Q statistic and quantifed by I2 statistics.RESULTS： Four distinct studies with a total of 920 pa-tients, mean age 59.83 （95%CI： 56.77-62.83） years, were included in the review. The additional adenoma detection rate （AADR） defined as the number of ad-ditional adenomas identified due to “third eye retro-scope” device in comparison to standard colonoscopy alone was 19.9% （95%CI： 7.3-43.9）. AADR for right and left colon were 13.9% （95%CI： 9.4-20） and 10.7 （95%CI： 1.9-42）, respectively. AADR for polyps ≥ 6 mm and ≥ 10 mm were 24.6% （95%CI： 16.6-34.9） and 24.2% （95%CI： 12.9-40.8）, respectively. The ad-ditional polyp detection rate defined as the number of additional polyps identifed due to “third eye retro-scope” device in comparison to standard colonoscopyalone was 19.8% （95%CI： 7.9-41.8）. There were no complications reported with use of “third eye retro-scope” device.CONCLUSION： The “third eye retroscope” device when used with standard colonoscopy is safe and de-tects 19.9% additional adenomas, compared to stan-dard colonoscopy alone.

Association of trainee participation with adenoma and polyp detection rates

To investigate whether adenoma and polyp detection rates (ADR and PDR, respectively) in screening colonoscopies performed in the presence of fellows differ from those performed by attending physicians alone. METHODSWe performed a retrospective review of all patients who underwent a screening colonoscopy at Grady Memorial Hospital between July 1, 2009 and June 30, 2015. Patients with a history of colon polyps or cancer and those with poor colon preparation or failed cecal intubation were excluded from the analysis. Associations of fellowship training level with the ADR and PDR relative to attendings alone were assessed using unconditional multivariable logistic regression. Models were adjusted for sex, age, race, and colon preparation quality. RESULTSA total of 7503 colonoscopies met the inclusion criteria and were included in the analysis. The mean age of the study patients was 58.2 years; 63.1% were women and 88.2% were African American. The ADR was higher in the fellow participation group overall compared to that in the attending group: 34.5% vs 30.7% (P = 0.001), and for third year fellows it was 35.4% vs 30.7% (aOR = 1.23, 95%CI: 1.09-1.39). The higher ADR in the fellow participation group was evident for both the right and left side of the colon. For the PDR the corresponding figures were 44.5% vs 40.1% (P = 0.0003) and 45.7% vs 40.1% (aOR = 1.25, 95%CI: 1.12-1.41). The ADR and PDR increased with increasing fellow training level (P for trend < 0.05). CONCLUSIONThere is a stepwise increase in ADR and PDR across the years of gastroenterology training. Fellow participation is associated with higher adenoma and polyp detection.

Artificial intelligence in polyp detection-where are we and where are we headed?

The goal of artificial intelligence in colonoscopy is to improve adenoma detection rate and reduce interval colorectal cancer.Artificial intelligence in polyp detection during colonoscopy has evolved tremendously over the last decade mainly due to the implementation of neural networks.Computer aided detection(CADe)utilizing neural networks allows real time detection of polyps and adenomas.Current CADe systems are built in single centers by multidisciplinary teams and have only been utilized in limited clinical research studies.We review the most recent prospective randomized controlled trials here.These randomized control trials,both non-blinded and blinded,demonstrated increase in adenoma and polyp detection rates when endoscopists used CADe systems vs standard high definition colonoscopes.Increase of polyps and adenomas detected were mainly small and sessile in nature.CADe systems were found to be safe with little added time to the overall procedure.Results are promising as more CADe have shown to have ability to increase accuracy and improve quality of colonoscopy.Overall limitations included selection bias as all trials built and utilized different CADe developed at their own institutions,non-blinded arms,and question of external validity.

Colonoscopy quality with Entonox? vs intravenous conscious sedation:18608 colonoscopy retrospective study

AIM To compare colonoscopy quality with nitrous oxide gas(Entonox?) against intravenous conscious sedation using midazolam plus opioid.METHODS A retrospective analysis was performed on a prospectively held database of 18608 colonoscopies carried out in Lothian health board hospitals between July 2013 and January 2016.The quality of colonoscopies performed with Entonox was compared to intravenous conscious sedation(abbreviated in this article as IVM).Furthermore,the quality of colonoscopies performed with an unmedicated group was compared to IVM.The study used the following key markers of colonoscopy quality:(1) patient comfort scores;(2) caecal intubation rates(CIRs); and (3) polyp detection rates (PDRs).We used binary logistic regression to model the data.RESULTS There was no difference in the rate of moderate-toextreme discomfort between the Entonox and IVM groups (17.9% vs 18.8%; OR = 1.06,95%CI: 0.95-1.18,P = 0.27).Patients in the unmedicated group were less likely to experience moderate-to-extreme discomfort than those in the IVM group(11.4% vs 18.8%; OR = 0.71,95%CI: 0.60-0.83,P < 0.001).There was no difference in caecal intubation between the Entonox and IVM groups(94.4% vs 93.7%; OR = 1.08,95%CI: 0.92-1.28,P = 0.34).There was no difference in caecal intubation between the unmedicated and IVM groups (94.2% vs 93.7%; OR = 0.98,95%CI: 0.79-1.22,P = 0.87).Polyp detection in the Entonox group was not different from IVM group (35.0% vs 33.1%; OR = 1.01,95%CI: 0.93-1.10,P = 0.79).Polyp detection in the unmedicated group was not significantly different from the IVM group (37.4% vs 33.1%; OR = 0.97,95%CI: 0.87-1.08,P = 0.60).CONCLUSION The use of Entonox was not associated with lower colonoscopy quality when compared to intravenous conscious sedation using midazolam plus opioid.

Withdrawal time in excellent or very poor bowel preparation qualities

AIM: To evaluate association(s) between withdrawal time and polyp detection in various bowel preparation qualities. METHODS: Retrospective cohort analysis of screening colonoscopies performed between January 2005 and June 2011 for patients with average risk of colorectal cancer. Exclusion criteria included patients with a personal history of adenomatous polyps or colon cancer, prior colonic resection, significant family history of colorectal cancer, screening colonoscopy after other abnormal screening tests such as flexible sigmoidoscopy or barium enema, and screening colonoscopies during in-patient care. All procedures were performed or directly supervised by gastroenterologists. Main measurements were number of colonic segments with polyps and total number of colonic polyps.RESULTS: Multivariate analysis of 8331 colonosco-pies showed longer withdrawal time was associated with more colonic segments with polyps in good(adjusted OR = 1.16; 95%CI: 1.13-1.19), fair(OR = 1.13; 95%CI: 1.10-1.17), and poor(OR = 1.18; 95%CI: 1.11-1.26) bowel preparation qualities. A higher number of total polyps was associated with longer withdrawal time in good(OR = 1.15; 95%CI: 1.13-1.18), fair(OR = 1.13; 95%CI: 1.10-1.16), and poor(OR = 1.20; 95%CI: 1.13-1.29) bowel preparation qualities. Longer withdrawal time was not associated with more colonic segments with polyps or greater number of colonic polyps in bowel preparations with excellent(OR = 1.07, 95%CI: 0.99-1.26; OR = 1.11, 95%CI: 0.99-1.24, respectively) and very poor(OR = 1.02, 95%CI: 0.99-1.12; OR = 1.05, 95%CI: 0.99-1.10, respectively) qualities.CONCLUSION: Longer withdrawal time is not associated with higher polyp number detected in colonoscopies with excellent or very poor bowel preparation quality.

Improving Colonoscopy Polyp Detection Rate Using Semi-Supervised Learning

Colorectal cancer is one of the biggest health threats to humans and takes thousands of lives every year.Colonoscopy is the gold standard in clinical practice to inspect the intestinal wall,detect polyps and remove polypsin early stages,preventing polyps from becoming malignant and forming colorectal cancer instances.In recentyears,computer-aided polyp detection systems have been widely used in colonoscopies to improve the qualityof colonoscopy examination and increase the polyp detection rate.Currently,the most efficient computer-aidedsystems are built with machine learning methods.However,developing such a computer-aided detection systemrequires experienced doctors to label a large number of image data from colonoscopy videos,which is extremelytime-consuming,laborious and expensive.One possible solution is to adopt a semi-supervised learning,which canbuild a detection system on a dataset where part of its data is not necessary to be labeled.In this paper,on thebasis of state-of-the-art object detection method and semi-supervised learning technique,we design and implementa semi-supervised colonoscopy polyp detection system containing four main steps:running standard supervisedtraining with all labeled data;running inference on unlabeled data to obtain pseudo labels;applying a set ofstrong augmentation to both unlabeled data and pseudo label;combining labeled data,and unlabeled data withits pseudo labels to retrain the detector.The semi-supervised learning system is evaluated both on public datasetand our original private dataset and proves its effectiveness.Also,the inference speed of the semi-supervisedlearning system can meet the requirement of real-time operation.