Impact of wide-angle, high-definition endoscopy in the diagnosis of colorectal neoplasia: a randomized controlled trial

Evaluation of super resolution technology for digestive endoscopic images

Object

This study aims to evaluate the value of super resolution (SR) technology in augmenting the quality of digestive endoscopic images.

Methods

In the retrospective study, we employed two advanced SR models, i.e., SwimIR and ESRGAN. Two discrete datasets were utilized, with training conducted using the dataset of the First Affiliated Hospital of Soochow University (12,212 high-resolution images) and evaluation conducted using the HyperKvasir dataset (2,566 low-resolution images). Furthermore, an assessment of the impact of enhanced low-resolution images was conducted using a 5-point Likert scale from the perspectives of endoscopists. Finally, two endoscopic image classification tasks were employed to evaluate the effect of SR technology on computer vision (CV).

Results

SwinIR demonstrated superior performance, which achieved a PSNR of 32.60, an SSIM of 0.90, and a VIF of 0.47 in test set. 90 % of endoscopists supported that SR preprocessing moderately ameliorated the readability of endoscopic images. For CV, enhanced images bolstered the performance of convolutional neural networks, whether in the classification task of Barrett's esophagus (improved F1-score: 0.04) or Mayo Endoscopy Score (improved F1-score: 0.04).

Conclusions

SR technology demonstrates the capacity to produce high-resolution endoscopic images. The approach enhanced clinical readability and CV models' performance of low-resolution endoscopic images.

Factors Associated with Polyp Detection Rate in European Colonoscopy Practice: Findings of The European Colonoscopy Quality Investigation (ECQI) Group

Background: The European Colonoscopy Quality Investigation (ECQI) Group aims to raise awareness for improvement in colonoscopy standards across Europe. We analysed data collected on a sample of procedures conducted across Europe to evaluate the achievement of the polyp detection rate (PDR) target. We also investigated factors associated with PDR, in the hope of establishing areas that could lead to a quality improvement. Methods: 6445 form completions from 12 countries between 2 June 2016 and 30 April 2018 were considered for this analysis. We performed an exploratory analysis looking at PDR according to European Society of Gastrointestinal Endoscopy (ESGE) definition. Stepwise multivariable logistic regression analysis was conducted to determine the most influential associated factors after adjusting for the other pre-specified variables. Results: In our sample there were 3365 screening and diagnostic procedures performed in those over 50 years. The PDR was 40.5%, which is comparable with the ESGE minimum standard of 40%. The variables found to be associated with PDR were in descending order: use of high-definition equipment, body mass index (BMI), patient gender, age group, and the reason for the procedure. Use of HD equipment was associated with a significant increase in the reporting of flat lesions (14.3% vs. 5.7%, p < 0.0001) and protruded lesions (34.7% vs. 25.4%, p < 0.0001). Conclusions: On average, the sample of European practice captured by the ECQI survey meets the minimum PDR standard set by the ESGE. Our findings support the ESGE recommendation for routine use of HD colonoscopy.

Diagnostic Ability of High-definition Imaging Using Ultraslim Endoscopes in Early Gastric Cancer

Purpose

It is unclear whether high-definition (HD) imaging improves visibility and diagnostic ability in early gastric cancer (EGC) compared with standard-definition (SD) imaging. We aimed to compare the diagnostic performance and visibility scores of HD and SD ultraslim endoscopes in EGC.

Materials and Methods

We used HD and SD ultraslim endoscopes to obtain 60 images with similar compositions of gastric environments. Of the 60 images, 30 showed EGC (15 images for each modality) and 30 showed no EGC (15 images for each modality). Seventeen endoscopists evaluated the presence and location of the lesions in each image. Diagnostic ability was compared between modalities. The color difference between a lesion and the surrounding mucosa (ΔE) was measured and compared between the modalities.

Results

The ability of HD to detect EGC was significantly higher than that of SD (accuracy: 80.8% vs. 71.6%, P=0.017; sensitivity: 94.9% vs. 76.5%, P<0.001; positive predictive value, 76.2% vs. 55.3%, P<0.001; and negative predictive value (NPV), 94.1% vs. 73.5%, P<0.001). The ability of HD to determine the horizontal extent of EGC was significantly higher than that of SD (accuracy: 71.0% vs. 57.8%, P=0.004; sensitivity: 75.3% vs. 49.0%, P<0.001; NPV, 72.9% vs. 55.9%, P<0.001; and area under the curve: 0.891 vs. 0.631, P=0.038). The mean ΔE was significantly higher for HD than for SD (10.3 vs. 5.9, P=0.011).

Conclusions

The HD ultraslim endoscope showed a higher diagnostic performance in EGC than the SD endoscope because it provided good color contrast.

≥3 Nonadvanced Adenomas are More Common in the Era of Contemporary Colonoscopy and Not Associated With Metachronous Advanced Neoplasia

INTRODUCTION

Data from standard definition colonoscopy era demonstrate patients with an advanced adenoma (≥10 mm, villous features or high-grade dysplasia) or ≥3 nonadvanced adenomas are considered high-risk for metachronous advanced neoplasia (MAN). Low-risk adenoma (LRA) patients are those with 1 to 2, <10 mm tubular adenomas. High definition colonoscopy, split-dose bowel preparation, and attention to adenoma detection enhance diminutive adenoma detection. We compared baseline adenoma characteristics between patients undergoing colonoscopy in a historic cohort (HC) and contemporary cohort (CC) to determine if number of patients with ≥3 nonadvanced adenomas are increased in CC, and if those features are associated with MAN in CC.

MATERIALS AND METHODS

Patients undergoing their first colonoscopy in HC (<2006) and CC (≥2006) at age 50 and above were identified through natural language processing. Multivariable regression analysis compared baseline adenoma characteristics between HC and CC, and determined the association between baseline characteristics and MAN in CC patients.

RESULTS

In total, 255,074 colonoscopies were performed between 1990 and 2015. A total of 9773 colonoscopies performed in the HC and 59,531 in the CC were included. At baseline, CC patients were more likely to have ≥3 nonadvanced adenomas [odds ratio (OR): 2.1, 95% confidence interval (CI): 1.7-2.6]. In 3,377 CC patients undergoing follow-up colonoscopy, the risk of MAN did not differ between patients with LRA versus those with ≥3 nonadvanced adenomas (6.3% vs. 4.6%, OR: 1.4, CI: 0.58-3.5) including 3-4 (6.1%, OR: 1.4, CI: 0.52-3.6) and ≥5 (7.7%, OR: 1.8, CI: 0.23-14.6), although few patients had ≥5 nonadvanced adenomas.

CONCLUSIONS

Colonoscopy in the contemporary era increases detection of patients with ≥3 nonadvanced adenomas, which do not increase the risk of MAN compared with LRA patients. A similar surveillance to LRA patients should be considered for those patients.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

EndoL2H: Deep Super-Resolution for Capsule Endoscopy

Although wireless capsule endoscopy is the preferred modality for diagnosis and assessment of small bowel diseases, the poor camera resolution is a substantial limitation for both subjective and automated diagnostics. Enhanced-resolution endoscopy has shown to improve adenoma detection rate for conventional endoscopy and is likely to do the same for capsule endoscopy. In this work, we propose and quantitatively validate a novel framework to learn a mapping from low-to-high-resolution endoscopic images. We combine conditional adversarial networks with a spatial attention block to improve the resolution by up to factors of 8× , 10× , 12× , respectively. Quantitative and qualitative studies demonstrate the superiority of EndoL2H over state-of-the-art deep super-resolution methods Deep Back-Projection Networks (DBPN), Deep Residual Channel Attention Networks (RCAN) and Super Resolution Generative Adversarial Network (SRGAN). Mean Opinion Score (MOS) tests were performed by 30 gastroenterologists qualitatively assess and confirm the clinical relevance of the approach. EndoL2H is generally applicable to any endoscopic capsule system and has the potential to improve diagnosis and better harness computational approaches for polyp detection and characterization. Our code and trained models are available at https://github.com/CapsuleEndoscope/EndoL2H.

High-definition colonoscopy for improving adenoma detection: a systematic review and meta-analysis of randomized controlled studies

BACKGROUND AND AIMS

Previous meta-analysis showed marginal benefit of high-definition white-light endoscopy (HD-WLE) over standard-definition colonoscopy (SDC) for adenoma detection, but with residual uncertainty due to inclusion of nonrandomized studies. We aimed to further assess the effect of HD-WLE on adenoma detection by including only randomized controlled trials (RCTs).

METHODS

A literature search was performed for RCTs evaluating HD-WLE versus SDC in terms of adenoma, advanced adenoma, and serrated sessile adenoma detection rates as well as the mean number of adenomas per colonoscopy (MAC), the mean number of advanced adenomas per colonoscopy (MAAC), and the mean number of sessile serrated adenomas per colonoscopy (MSSAC). The effect size on study outcomes is presented as the risk ratio (RR; 95% confidence interval [CI]) or mean difference (MD; 95% CI). We assessed the strength of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Six RCTs involving 4594 individuals (HD-WLE, 2323; SDC, 2271) were included. Clinical indications were screening (1 study), positive result for fecal occult blood test, personal/family history of colorectal cancer (1 study), and mixed indications (4 studies). Withdrawal time was similar between the 2 arms (MD, -0.06; 95% CI, -0.25 to 0.12; P = .50). The adenoma detection rate was significantly higher in the HD-WLE arm compared with the SDC arm (40% vs 35%; RR, 1.13; 95% CI, 1.05-1.22; P = .001; I² = 0%; GRADE, low). This effect was consistent for advanced and sessile serrated adenoma detection rates (RR, 1.33; 95% CI, 1.03-1.72; P = .03; I² = 0%; GRADE, low; and RR, 1.55; 95% CI, 1.05-2.28; P = .03; I² = 0%; GRADE, low, respectively). In contrast, the difference was not significant for MAC, MAAC, and MSSAC.

CONCLUSIONS

Meta-analyses of RCT data support the use of HD-WLE in clinical practice, although the additional benefit is limited.

Comparison of the detection of colorectal lesions in different endoscopic modalities: A network meta-analysis and systematic review

A colonoscopy is considered to be the standard diagnostic test used to detect early colorectal lesions. Detection rates are expected to improve with optimised visualisation. A systematic review and network meta-analysis was conducted to evaluate detection efficiency in several colonoscopic modalities. Relevant articles were identified in searches of the PubMed, EMBASE and Cochrane Library databases. The modalities, comprising of standard-definition white light (SDWL), high-definition white light (HDWL), narrow-band imaging (NBI), autofluorescence imaging (AFI), PENTAX image enhanced technology (i-SCAN), Fuji Intelligent Color Enhancement (FICE), dye-based chromoendoscopy and novel image enhanced systems, including blue laser imaging (BLI) and linked color imaging (LCI), were compared to identify the most efficient modalities that could be used to detect colorectal lesions. Odds ratios (ORs) and mean differences (MDs) with 95% confidence intervals (CIs) were calculated. As a result, 40 studies fulfilled the inclusion criteria. Overall, in the network meta-analyses, NBI (OR, 1.29; 95% CI, 1.04-1.58), FICE (OR, 1.39; 95% CI, 1.11-1.77), chromoendoscopy (OR, 1.53; 95% CI, 1.22-1.93) and AFI (OR, 1.81; 95% CI, 1.07-2.87) were significantly better compared with SDWL at identifying adenoma in patients, and chromoendoscopy also proved significantly superior to HDWL (OR, 1.30; 95% CI, 1.06-1.60). In pairwise analyses, it was demonstrated that chromoendoscopy was significantly superior to HDWL at detecting the number of polyps (MD, -1.11; 95% CI, -1.46, -0.76) and flat lesions (MD, -0.30; 95% CI, -0.49, -0.10) per subject. Additionally, FICE detected a significantly greater number of subjects with polyps (OR, 0.78; 95% CI, 0.64-0.96) and NBI was significantly better at detecting the number of subjects with flat lesions (OR, 0.77; 95% CI, 0.60-0.99) compared with HDWL. Based on the meta-analysis, NBI, FICE and AFI were significantly better compared with SDWL at detecting patients with adenoma. Additionally, chromoendoscopy was significantly better than SDWL and HDWL at detecting the number of colorectal adenoma, however additional studies are needed to confirm these findings.

Miniaturized omnidirectional flexible side-view endoscope for rapid monitoring of thin tubular biostructures

Endoscopic imaging allows longitudinal observation of epithelial pathologies in tubular organs throughout the body. However, the imaging and optical diagnosis of tubular biostructures such as small animal models and small pediatric organs require appropriately miniaturized devices. A miniaturized catadioptric flexible side-view endoscope is proposed with omnidirectional field of view (FOV) in the transverse direction and sub-mm-scale feature resolution. The FOV in the longitudinal direction is 50°. Images are unwrapped and stitched together to form composite images of the target by two different algorithms, revealing a composite FOV of more than 3.5 cm × 360°. The endoscope is well suited for minimally invasive rapid monitoring of thin tubular organs in pediatric patients, as well as for imaging of small animal disease models at near-cellular resolution.

Improvement of arthroscopic surgical performance using a new wide-angle arthroscope in the surgical training

Background

We have developed a new arthroscope with a field of view of 150°. This arthroscope requires less motion to maneuver and exhibits reduced optical error. It also improves how novices learn arthroscopy. We hypothesized that the surgical performance with this arthroscope is superior to that with a conventional arthroscope. This study tested the hypothesis by using motion analysis and a new validated parameter, “dimensionless squared jerk” (DSJ).

Methods

We compared the surgical performance between the use of the wide-angle arthroscope and that of the conventional arthroscope among 14 novice orthopedic residents who performed 3 standardized tasks 3 times with each arthroscope. The tasks simulated the surgical skills in arthroscopic rotator cuff repair. The arthroscope motion was analyzed using an optical tracking system. The differences in performance parameters, such as the time taken to complete the tasks, average acceleration of the hands (m/s²), number of movements, and total path length (m) including DSJ between the 2 arthroscopes were investigated using paired t-tests.

Results

All estimated values for the tasks using the 150° arthroscope were lower than those for the tasks using the 105° arthroscope. Statistically significant differences in performance between the 2 arthroscopes were observed only for DSJ (p = 0.014) and average acceleration (p = 0.039).

Conclusions

DSJ and average acceleration are reliable parameters for representing hand-eye coordination. The surgical performance of novice arthroscopists was better with the new wide-angle arthroscope than with the conventional arthroscope.

Role of Full-spectrum Endoscopy in Colorectal Cancer Screening: Randomized Trial

GOALS

The aim of this study was to compare a new, full-spectrum endoscope (Fuse; EndoChoice, Alpharetta, GA) to standard forward-viewing colonoscopy in the detection of colorectal neoplasms.

BACKGROUND

Colonoscopy, the gold standard for the detection of colorectal cancer, fails to detect 22% to 28% of polyps, increasing the risk of interval cancer. Endoscopic improvement of the adenoma detection rate decrease interval carcinomas. Full-spectrum endoscopy (FUSE) (330-degree field of view), in a tandem study, has been shown to reduce the adenoma miss rate.

STUDY

Prospective, randomized study of 249 patients in patients referred from the colorectal screening program with a positive fecal occult blood test (FOBT). Patients were randomized to standard forward-viewing colonoscopy (170 degrees) or to full-spectrum colonoscopy with the Fuse system (330 degrees). Study variables were the adenoma detection rate, the polyp detection rate, the mean number of adenomas per procedure, the lesions detected according to the location, morphology and size, cecal intubation rate, total procedure time, insertion time to the cecum, therapeutic success, and adverse events.

RESULTS

The Fuse system did not produce a significantly higher adenoma detection rate than standard forward-viewing colonoscopy (FUSE 73.1% vs. standard colonoscopy 68.1%; P=0.47) but did have a significantly longer insertion time (FUSE 6.2 min vs. standard colonoscopy 4.2 min; P< 0.001). Further analysis failed to reveal any significant difference in polyp/adenoma detection rates by lesion size or colonic section.

CONCLUSIONS

FUSE did not detect significantly more colorectal neoplasia than forward viewing colonoscopy in a medium-risk CRC screening population with positive FOBT.

The Dimensionless Squared Jerk: An Objective Parameter That Improves Assessment of Hand Motion Analysis during Simulated Shoulder Arthroscopy

PURPOSE

Attempts to quantify hand movements of surgeons during arthroscopic surgery faced limited progress beyond motion analysis of hands and/or instruments. Surrogate markers such as procedure time have been used. The dimensionless squared jerk (DSJ) is a measure of deliberate hand movements. This study tests the ability of DSJ to differentiate novice and expert surgeons (construct validity) whilst performing simulated arthroscopic shoulder surgical tasks.

METHODS

Six residents (novice group) and six consultants (expert group) participated in this study. Participants performed three validated tasks sequentially under the same experimental setup (one performance). Each participant had ten performances assessed. Hand movements were recorded with optical tracking system. The DSJ, time taken, total path length, multiple measures of acceleration, and number of movements were recorded.

RESULTS

There were significant differences between novices and experts when assessed using time, number of movements with average and minimal acceleration threshold, and DSJ. No significant differences were observed in maximum acceleration, total path length, and number of movements with 10m/s2 acceleration threshold.

CONCLUSION

DSJ is an objective parameter that can differentiate novice and expert surgeons' simulated arthroscopic performances. We propose DSJ as an adjunct to more conventional parameters for arthroscopic surgery skills assessment.

Is there a difference in adenoma detection rates between gastroenterologists and surgeons?

AIM

To compare the adenoma detection rate (ADR) between gastroenterologists and colorectal surgeons at Box Hill Hospital, Melbourne, Australia.

METHODS

A total of 300 colonoscopies performed by gastroenterologists and colorectal surgeons at Box Hill Hospital were retrospectively reviewed from May 2016 to June 2017. Exclusion criteria were: Patients ≤ 50 years old, colonoscopies with failure of caecal intubation, patients who previously had colon cancer and/or a colonic resection, history of polyposis syndromes or inflammatory bowel disease, or a colonoscopy within the last 10 years. Patient demographics, indications, symptoms and procedural-related outcomes were measured.

RESULTS

The ADR was not significantly different between gastroenterologists and colorectal surgeons (34% vs 34.67%; P = 0.90). The adjusted odds ratio correcting for gender, age, 1^st degree relative with colorectal cancer, previous colonoscopy, trainee involvement and caecal or terminal ileum intubation rate was 1.19 (0.69-2.05).

CONCLUSION

Both specialties at our institution exceed benchmark standards suggested by published Australian and American guidelines. An association between endoscopist specialty and ADR was not observed.

Choi C, Kim SJ, Nam HS, Ryu DG, Hong JB, Kim DJ. Cimetropium bromide does not improve polyp and adenoma detection during colonoscope withdrawal: A randomized, double-blind, placebo-controlled study

BACKGROUND

Endoscopic inspection of colonic mucosa is disturbed by colonic folds and peristalsis, which may result in missed polyps. Cimetropium bromide, an antispasmodic agent, inhibits peristalsis and colonic spasms, which may improve polyp detection. The purpose of this randomized, double-blind, placebo-controlled study was to investigate whether cimetropium bromide could improve polyp and adenoma detection in the colorectum and right colon.

METHODS

Patients undergoing screening or diagnostic colonoscopy were randomized to receive intravenous cimetropium bromide (5 mg) or placebo after cecal intubation. The primary outcomes were the number of polyps per patient (PPP) and adenomas per patient (APP); secondary outcomes were the polyp detection rate (PDR), adenoma detection rate (ADR), and advanced neoplasm detection rate (ANDR).

RESULTS

A total of 181 patients were analyzed; 91 patients received cimetropium bromide and 90 patients received placebo. Cimetropium bromide and placebo groups did not significantly differ in the PPP and APP for the colorectum (1.38 ± 1.58 vs 1.69 ± 2.28, P = .298; 0.96 ± 1.27 vs 1.11 ± 1.89, P = .517, respectively) and right colon (0.70 ± 0.95 vs 0.78 ± 1.21, P = .645; 0.47 ± 0.81 vs 0.51 ± 0.81, P = .757, respectively). Two groups also did not significantly differ in the PDR, ADR, and ANDR for the colorectum and right colon. Furthermore, there were no difference between groups in the PPP, APP, PDR, ADR, and ADNR in a sub-analysis of expert and non-expert endoscopists.

CONCLUSIONS

Cimetropium bromide did not improve polyp and adenoma detection in the colorectum and right colon during colonoscope withdrawal, regardless of the expertness of the endoscopist. However, its use may be helpful in patients with active peristalsis or for beginning endoscopists during standard colonoscopy without a transparent cap.

Can technology increase adenoma detection rate?

Colorectal cancer is the third most common cancer worldwide and the second most common cause of cancer-related death in Europe and North America. Colonoscopy is the gold standard investigation for the colon but is not perfect, and small or flat adenomas can be missed which increases the risk of patients subsequently developing colorectal cancer. Adenoma detection rate is the most widely used marker of quality, and low rates are associated with increased rates of post-colonoscopy colorectal cancer. Standards of colonoscopy and adenoma detection vary widely between different endoscopists. Interventions to improve adenoma detection rate are therefore required. Many devices have been purported to increase adenoma detection rate. This review looks at current available evidence for device technology to improve adenoma detection rate during colonoscopy.

Technological advances for improving adenoma detection rates: The changing face of colonoscopy

Worldwide, colorectal cancer is the third commonest cancer. Over 90% follow an adenoma-to-cancer sequence over many years. Colonoscopy is the gold standard method for cancer screening and early adenoma detection. However, considerable variation exists between endoscopists' detection rates. This review considers the effects of different endoscopic techniques on adenoma detection. Two areas of technological interest were considered: (1) optical technologies and (2) mechanical technologies. Optical solutions, including FICE, NBI, i-SCAN and high definition colonoscopy showed mixed results. In contrast, mechanical advances, such as cap-assisted colonoscopy, FUSE, EndoCuff and G-EYE™, showed promise, with reported detections rates of up to 69%. However, before definitive recommendations can be made for their incorporation into daily practice, further studies and comparison trials are required.

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.

[New Colonoscopy Devices to Improve Colon Neoplasm Detection]

Early detection and removal of adenomatous polyps can prevent the development of colorectal cancer. However, it is fairly common-up to 20%-for polyps to be undetected in a colonoscopy due to poor visualization of the proximal aspect of colonic folds and anatomical flexures. To overcome these limitations, many new endoscopes and accessories have been developed. A wide-angle colonoscopy did not improve the detection of adenoma compared with the standard colonoscopy. An extra-wide angle and Retroview colonoscopies showed a significantly lower miss rate of polyps in the colon model. However, clinical trials are mandatory in the future. The recently introduced full spectrum endoscopy system showed a significantly higher adenoma detection rate than the standard forward-viewing colonoscopy. In accessories, The cap-assisted colonoscopy showed only a marginal or no benefit on the detection of polyps and adenomas. In contrast, a colonoscopy with Endocuff, EndoRings, and G-eye have showed significantly lower adenoma miss rates. The Third Eye, which provides additional retrograde viewing, has revealed a significant improvement in the detection of adenoma and polyp. However, the Third Eye Retroscope was limited by its deployment through the working channel of the scope. Recently, the Third Eye Panoramic cap, which was designed to overcome the limitation of the Third Eye Retroscope, was introduced. In the future, this would be needed to evaluate the effectiveness, efficiency and safety for these new colonoscopies and accessories.

Enhanced flat adenoma detection rate with high definition colonoscopy plus i-scan for average-risk colorectal cancer screening

BACKGROUND AND AIM

The usefulness of high definition colonoscopy plus i-scan (HD+i-SCAN) for average-risk colorectal cancer screening has not been fully assessed. The detection rate of adenomas and other measurements such as the number of adenomas per colonoscopy and the flat adenoma detection rate have been recognized as markers of colonoscopy quality. The aim of the present study was to compare the diagnostic performance of an HD+i-SCAN with that of standard resolution white-light colonoscope.

METHODS

This is a retrospective analysis of a prospectively collected screening colonoscopy database. A comparative analysis of the diagnostic yield of an HD+i-SCAN or standard resolution colonoscopy for average-risk colorectal screening was conducted.

RESULTS

During the period of study, 155/163 (95.1%) patients met the inclusion criteria. The mean age was 56.9 years. Sixty of 155 (39%) colonoscopies were performed using a HD+i-SCAN. Adenoma-detection-rates during the withdrawal of the standard resolution versus HD+i-SCAN colonoscopies were 29.5% and 30% (p = n.s.). Adenoma/colonoscopy values for standard resolution versus HD+i-SCAN colonoscopies were 0.46 (SD = 0.9) and 0.72 (SD = 1.3) (p = n.s.). A greater number of flat adenomas were detected in the HD+i-SCAN group (6/60 versus 2/95) (p < .05). Likewise, serrated adenomas/polyps per colonoscopy were also higher in the HD+i-SCAN group.

CONCLUSIONS

A HD+i-SCAN colonoscopy increases the flat adenoma detection rate and serrated adenomas/polyps per colonoscopy compared to a standard colonoscopy in average-risk screening population. HD+i-SCAN is a simple, available procedure that can be helpful, even for experienced providers. The performance of HD+i-SCAN and substantial prevalence of flat lesions in our average-risk screening cohort support its usefulness in improving the efficacy of screening colonoscopies.

Expert opinions and scientific evidence for colonoscopy key performance indicators

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

Can Technology Improve the Quality of Colonoscopy?

In order for screening colonoscopy to be an effective tool in reducing colon cancer incidence, exams must be performed in a high-quality manner. Quality metrics have been presented by gastroenterology societies and now include higher adenoma detection rate targets than in the past. In many cases, the quality of colonoscopy can often be improved with simple low-cost interventions such as improved procedure technique, implementing split-dose bowel prep, and monitoring individuals' performances. Emerging technology has expanded our field of view and image quality during colonoscopy. We will critically review several technological advances in the context of quality metrics and discuss if technology can really improve the quality of colonoscopy.

High-definition colonoscopy increases adenoma detection rate

BACKGROUND

The adenoma detection rate (ADR) is a quality indicator for colonoscopy. High-definition (HD) imaging has been reported to increase polyp detection rates.

OBJECTIVE

The primary objective of this study was to compare polyp detection rate (PDR) and adenoma detection rate (ADR) before and after the implementation of HD colonoscopy.

METHODS

A retrospective chart review was performed on patients aged 48-55 years old, who underwent first-time screening colonoscopy. The first group underwent standard-definition (SD) colonoscopy in the first 6 months of 2011. The second group underwent screening with HD colonoscopy during the first 6 months of 2012. We compared age, gender, PDR, ADR, and average sizes of adenomatous polyps between gastroenterologist and colorectal surgeon and among physicians themselves. Statistical analysis was performed with Fischer's exact test and Pearson Chi-square.

RESULTS

A total of 1268 patients were involved in the study (634 in each group). PDR (35.6 vs. 48.2 %, p < 0.001) and ADR (22.2 vs. 30.4 %, p = 0.02) were higher in the HD group. The average size of an adenomatous polyp was the same in the two groups (0.58 vs. 0.57, p = 0.69). However, this difference was not seen among colorectal surgeons PDR (35.7 vs. 37 %, p = 0.789), ADR (22.9 vs. 24.5 % p = 0.513), but clearly seen among gastroenterologist, PDR (35.6 vs. 53.1 % p < 0.001) and ADR (21.9 vs. 32.9 % p < 0.001). When polyps were categorized into size groups, there was no difference in ADR between the two timeframes (<5 mm in size (41.5 vs. 35.4 %), 5-10 mm (49.3 vs. 60.1 %) and >10 mm (9.2 vs. 4.5 %), p = 0.07). Polyps were most commonly seen in the sigmoid colon (26.1 vs. 24.7 %). There was no difference in the rate of synchronous polyp detection between modalities (25.6 vs. 29 %, p = 0.51). Withdrawal time was the same in both procedure (9.2 vs. 8.5 min, p = 0.10).

CONCLUSION

Screening colonoscopy with high-definition technology significantly improved both PDR and ADR. In addition, high-definition colonoscopy may be particularly useful and advantageous among less experienced endoscopists in various community settings. However, there needs to be application to specific patient populations in future studies to assess for any statistical differences between standard- and high-definition modalities to determine clinical utility.

A new wide-angle arthroscopic system: a comparative study with a conventional 30° arthroscopic system

PURPOSE

To compare users' hand movements in performing validated shoulder arthroscopic tasks between a 30° and a wide-angle arthroscopic system, using phantom models with an optical motion analysis system.

METHODS

Twelve orthopaedic residents were enrolled and randomly allocated into two groups. In order to compensate for any learning effect, a Latin square counterbalancing technique was used. An optical motion analysis system was used with markers affixed to pre-designed sites; each participant conducted four validated shoulder arthroscopic tasks using both arthroscopic systems. Each participant was instructed to perform the experiment three times with each arthroscope. The time taken, total path length, number of movements, and average acceleration were analysed.

RESULTS

Significant differences were observed for the time taken, number of movements, and average acceleration between the two arthroscopic systems (P < 0.05 for all). However, the time taken was not significant. The mean total path length measured 53 ± 38 cm with the 30° arthroscope, while the mean with the wide-angle arthroscope was significantly shorter, at 36 ± 22 cm. The mean number of movements with the 30° and wide-angle arthroscopes were 1974 ± 1305 and 1233 ± 990, respectively, while the average accelerations were 2.6 ± 1.3 and 1.2 ± 0.6 cm/s(2), respectively. The mean time taken was 13 % faster when using the wide-angle arthroscopic system, although this was not statistically significant.

CONCLUSION

The wide-angle arthroscopic system improved the arthroscope manoeuvre in terms of the total path length, number of movements, and average acceleration required for experimental arthroscopy. This system may help surgeons triangulate the arthroscope and surgical instruments during surgery by expanding the field of view.

Feasibility of full-spectrum endoscopy: Korea’s first full-spectrum endoscopy colonoscopic trial

AIM: To evaluate the full-spectrum endoscopy (FUSE) colonoscopy system as the first report on the utility thereof in a Korean population.

METHODS: We explored the efficacy of the FUSE colonoscopy in a retrospective, single-center feasibility study performed between February 1 and July 20, 2015. A total of 262 subjects (age range: 22-80) underwent the FUSE colonoscopy for colorectal cancer screening, polyp surveillance, or diagnostic evaluation. The cecal intubation success rate, the polyp detection rate (PDR), the adenoma detection rate (ADR), and the diverticulum detection rate (DDR), were calculated. Also, the success rates of therapeutic interventions were evaluated with biopsy confirmation.

RESULTS: All patients completed the study and the success rates of cecal and terminal ileal intubation were 100% with the FUSE colonoscope; we found 313 polyps in 142 patients and 173 adenomas in 95. The overall PDR, ADR and DDR were 54.2%, 36.3%, and 25.2%, respectively, and were higher in males, and increased with age. The endoscopists and nurses involved considered that the full-spectrum colonoscope improved navigation and orientation within the colon. No colonoscopy was aborted because of colonoscope malfunction.

CONCLUSION: The FUSE colonoscopy yielded a higher PDR, ADR, DDR than did traditional colonoscopy, without therapeutic failure or complications, showing feasible, effective, and safe in this first Korean trial.

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

Background/Aims:

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

Methods:

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

Results:

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

Conclusions:

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

Adenoma detection at colonoscopy by polypectomy in withdrawal only versus both insertion and withdrawal: a randomized controlled trial

Colonic configuration during insertion phase (IP) and withdrawal phase (WP) is different and some polyps seen during IP are difficult to find during WP and vice versa. To determine if polypectomy performed during both IP and WP of colonoscopy (study arm) increases adenoma detection rate (ADR) compared to WP only (control arm). In this prospective randomized controlled trial, adults undergoing out-patient colonoscopy were enrolled. The primary outcome was mean number of adenomas detected per patient. Secondary outcomes were ADR, defined as the proportion of colonoscopies with at least one adenoma, polyp detection rates (PDR), number of patients classified as high-risk group (presence of ≥3 adenomas of any size, any adenoma ≥1 cm in size, or adenoma with villous component, or high grade dysplasia), procedural times, patients discomfort, and ease of procedure. Among 772 patients enrolled, 610 were included (329 in study arm and 281 in control arm). In both arms, mean number of adenomas detected per patient were similar, 0.78 ± 1.4 vs. 0.74 ± 1.5, P = 0.75. Also, ADR (39.2 vs. 38.1 %, P = 0.77) and PDR (57.1 and 54.1 %, P = 0.45) were similar. Mean insertion time was significantly higher in study arm (10.2 ± 5.8 vs. 9.3 ± 5.6 min, p = 0.046). Proportion of patients identified as high-risk group were significantly higher in study arm (18.8 vs. 11.7 %, P = 0.016).

CONCLUSIONS

Polypectomy performed during both IP and WP compared to the WP only, did not improve ADR or mean number of adenomas detected per patient.

TRIAL REGISTRATION

Clinicaltrials.gov, #NCT01025960.

Gastrointestinal tract-derived pulse granulomata: clues to an underrecognized pseudotumor

Pulse granulomata (PG) in the lung and oral pathology literature are presumed due to food (pulse) introduced by mucosal injury. Herein, we report the largest series of PG in the gastrointestinal tract (GIT): 22 resections were prospectively collected from 17 patients (8 men, range=28 to 85 y). All patients had a history of intestinal injury/disease: diverticulitis, fistula, adenocarcinoma, perforation, ulcerative colitis, appendicitis, anastomotic site leak, and/or stent leak. Nine of 22 specimens were designated "masses"; most of these were clinically concerning for neoplasia. Sites of involvement included the small and large intestine, appendix, liver, gallbladder, mesentery, omentum, peritoneum, cervix, ovary, and skin. PG were typically nodular (21/22) and multifocal (15/22); most involved the external surface of the bowel (20/22), and they ranged in size from 1.5 to 100 mm. Histologically, they contained variable amounts of hyaline ribbons and rings, inflammation, foreign body giant cells, calcifications, and food; larger lesions displayed circumferential stellate fibrosis (12/22). We describe 3 morphologic variants: hyaline predominant (mimicking amyloid), cellular predominant (mimicking spindle cell neoplasms), and sclerosing mesenteritis-like. All patients are alive and well at the time of follow-up. Histologically processed legumes showed similar structures as those identified in PG, providing support for an entrapped food origin. In summary, we detail important clinicopathologic clues, describe the PG morphologic spectrum, and demonstrate how to distinguish PG from their mimics. Although PG can present as clinically concerning masses, we conclude that they are pseudotumors arising secondary to entrapped food introduced through mucosal trauma, similar to their lung and oral counterparts.

Short turn radius colonoscope in an anatomical model: Retroflexed withdrawal and detection of hidden polyps

AIM: To evaluate the new RetroView™ colonoscope and compare its ability to detect simulated polyps “hidden” behind colonic folds with that of a conventional colonoscope, utilizing anatomic colon models.

METHODS: Three anatomic colon models were prepared, with twelve simulated polyps “hidden” behind haustral folds and five placed in easily viewed locations in each model. Five blinded endoscopists examined two colon models in random order with the conventional or RetroView™ colonoscope, utilizing standard withdrawal technique. The third colon model was then examined with the RetroView™ colonoscope withdrawn initially in retroflexion and then in standard withdrawal. Polyp detection rates during standard and retroflexed withdrawal of the conventional and RetroView™ colonoscopes were determined. Polyp detection rates for combined standard and retroflexed withdrawal (combination withdrawal) with the RetroView™ colonoscope were also determined.

RESULTS: For hidden polyps, retroflexed withdrawal using the RetroView™ colonoscope detected more polyps than the conventional colonoscope in standard withdrawal (85% vs 12%, P = 0.0001). For hidden polyps, combination withdrawal with the RetroView™ colonoscope detected more polyps than the conventional colonoscope in standard withdrawal (93% vs 12%, P≤ 0.0001). The RetroView™ colonoscope in “combination withdrawal” was superior to other methods in detecting all (hidden + easily visible) polyps, with successful detection of 80 of 85 polyps (94%) compared to 28 (32%) polyps detected by the conventional colonoscope in standard withdrawal (P < 0.0001) and 67 (79%) polyps detected by the RetroView™ colonoscope in retroflexed withdrawal alone (P < 0.01). Continuous withdrawal of the colonoscope through the colon model while retroflexed was achieved by all endoscopists. In a post-test survey, four out of five colonoscopists reported that manipulation of the colonoscope was easy or very easy.

CONCLUSION: In simulated testing, the RetroView™ colonoscope increased detection of hidden polyps. Combining standard withdrawal with retroflexed withdrawal may become the new paradigm for “complete screening colonoscopy”.

Endoscopists with low adenoma detection rates benefit from high-definition endoscopy

BACKGROUND

An endoscopists adenoma detection rate (ADR) of less than 20 % correlates with high risk for occurrence of interval cancer. The impact of high-definition (HD) imaging on the ADR is discussed controversially. We aimed to investigate whether detection rates of individual endoscopists increase within 1 year before and 1 year after the switch from standard to HD endoscopy.

METHODS

This cohort study analyzed 6,330 screening colonoscopies (2,968 with standard and 3,362 with HD) performed by 42 endoscopists between November 2007 and March 2013 within a nationwide quality assurance program for screening colonoscopy.

RESULTS

The ADR of endoscopists with a low ADR (<20 %) increased significantly higher (from 11.8 to 18.1 %, p = 0.003) than of those with a high ADR (≥ 20 %) (from 28.6 to 30.7 %, p = 0.439) after switch from standard to HD colonoscopes (p = 0.0076). The proportion of endoscopists with an ADR < 20 % decreased from 45 to 42.9 % (p = 0.593). There was no significant increase in age- and sex-adjusted detection rates of adenomas (20.2 vs 23.7 %; p = 0.089), advanced adenomas (4.7 vs 5.5 %; p = 0.479), flat adenomas (2.7 vs 3.1 %; p = 0.515), polyps (38.8 vs 41.5 %; p = 0.305), proximal polyps (18.5 vs 20 %; p = 0.469) and hyperplastic polyps (15 vs 17.2 %; p = 0.243) of endoscopists after switch to HD colonoscopes. There was no difference in detection rates of flat polyps (5.5 vs 5.5 %; p = 0.987).

CONCLUSIONS

The use of HD scopes is associated with marginal improvement in adenoma detection rates limited to those endoscopists with low adenoma detection rates prior to its introduction.

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.

Endoscopic mucosal imaging of gastrointestinal neoplasia in 2013

The holy grail of gastrointestinal endoscopy consists of the detection, in vivo characterization, and endoscopic removal of early or premalignant mucosal lesions. While our ability to achieve this goal has improved substantially since the development of the modern video-endoscope, inadequate visual inspection, errors of interpretation, and lesion subtlety all contribute to the continued suboptimal detection and assessment of early neoplasia. A myriad of new technologies has thus emerged that may help resolve these shortcomings; high magnification endoscopes, as well as the techniques of dye-based and virtual chromoendoscopy, are now widely available, while confocal laser endomicroscopy and endocystoscopy, optical coherence tomography, and autofluorescence imaging are generally applicable only in a research setting. Such technologies can be broadly categorized according to whether they potentially afford endoscopists improved detection, or real-time characterization, of mucosal lesions. Enhanced detection of otherwise "invisible" lesions, such as a flat area of intramucosal adenocarcinoma within Barrett's esophagus, carries the potential of an endoscopic cure prior to the development into a more advanced or metastatic disease. The ability to characterize a lesion to achieve an in vivo diagnosis, such as a colonic polyp, potentially affords endoscopists the ability to decide which lesions require removal and which can be safely left behind or discarded without histological assessment. Furthermore targeted biopsies, such as in the surveillance of chronic colitis, may prove to be more accurate and efficacious than the current protocol of random biopsies. An important caveat in the discussion of developing technologies in early cancer detection is the fundamental importance of a health-care system that promotes screening programs to recruit at-risk individuals. The ideal tool to optimize the use of endoscopy in population screening would be a panel of reliable biomarkers (blood, stool, or urine) that could effectively select a high-risk group, thus reducing the indiscriminate use of an expensive technology. The following review summarizes the current endoscopic imaging techniques available, and in development, for the early identification of gastrointestinal neoplasia.

Ancillary imaging techniques and adenoma detection

Advancements in image technology have allowed recognition of mucosal architecture in more detail and may improve adenoma detection. This review provides a technical overview on individual imaging technologies and their effect on detection of adenomas. Only high-definition endoscopy has been shown to improve detection of small adenomas. None of the digital chromoendoscopy technologies improves adenoma detection. Limited studies on autoimmunfluorescence imaging in conjunction with high-definition endoscopy may improve detection of small adenomas.

A novel method with significant impact on adenoma detection: combined water-exchange and cap-assisted colonoscopy

BACKGROUND

Water exchange provides salvage cleansing and improves adenoma detection, but drawbacks include prolonged procedure time. Cap-assisted colonoscopy decreases cecal intubation time but is limited by impaired views when feces lodge in the cap.

OBJECTIVE

To investigate the impact of combined water-exchange and cap-assisted colonoscopy (WCC) on detection of adenomas and proximal colon serrated polyps.

DESIGN

Retrospective, single-center, single-colonoscopist, consecutive group observational study.

SETTING

Veterans Affairs outpatient endoscopy suite.

PATIENTS

Outpatients undergoing screening or surveillance colonoscopy.

INTERVENTION

WCC data collected from 100 consecutive patients were compared to a control group of 101 consecutive patients examined with conventional air insufflation colonoscopy during the prior 4-month period.

MAIN OUTCOME MEASUREMENTS

Adenoma detection rate (ADR), adenomas detected per colonoscopy, proximal colon serrated polyp detection rate, and proximal colon serrated polyps per colonoscopy rate.

RESULTS

Compared with controls, the WCC group had a higher polyp detection rate (93.0% vs 84.2%; P = .07), ADR (75.0% vs 59.4%; P = .02), proximal colon ADR (61.0% vs 47.5%; P = .07), proximal colon serrated polyp detection rate (24.0% vs 9.9%; P = .009), number of adenomas per colonoscopy (2.70 vs 1.50; P = .002), and mean number of proximal colon serrated polyps per colonoscopy (0.38 vs 0.12; P = .004).

LIMITATIONS

Retrospective study; single, unblinded endoscopist.

CONCLUSION

ADR and adenomas per colonoscopy are both sensitive indicators of colonoscopy quality. WCC merges two simple methods to improve the performance of screening and surveillance colonoscopy. The data suggest that larger, prospective studies are necessary to determine if there are differences between water-exchange combined with cap-assisted maneuvers and the individual components used alone in lesion detection in screening and surveillance colonoscopy.

Differences in proximal serrated polyp detection among endoscopists are associated with variability in withdrawal time

BACKGROUND

Insufficient detection of proximal serrated polyps (PSP) might explain the occurrence of a proportion of interval carcinomas in colonoscopy surveillance programs.

OBJECTIVE

To compare PSP detection among endoscopists and to identify patient-related and endoscopist-related factors associated with PSP detection.

DESIGN

Prospective study in unselected patients.

SETTING

Colonoscopy screening program for colorectal cancer at two academic medical centers.

PATIENTS

Asymptomatic consecutive screening participants (aged 50-75 years).

INTERVENTION

Colonoscopies were performed by 5 experienced endoscopists. All detected polyps were removed. Multiple colonoscopy quality indicators were prospectively recorded.

MAIN OUTCOME MEASUREMENTS

We compared PSP detection among endoscopists by calculating odds ratios (OR) with logistic regression analysis. Logistic regression also was used to identify patient features and colonoscopy factors associated with PSP detection.

RESULTS

A total of 1354 patients underwent a complete screening colonoscopy: 1635 polyps were detected, of which 707 (43%) were adenomas and 685 (42%) were serrated polyps, including 215 PSPs. In 167 patients (12%) 1 or more PSPs were detected. The PSP detection rate differed significantly among endoscopists, ranging from 6% to 22% (P < .001). Longer withdrawal time (OR 1.12; 95% confidence interval, 1.10-1.16) was significantly associated with better PSP detection, whereas patient age, sex, and quality of bowel preparation were not.

LIMITATIONS

Limited number of highly experienced endoscopists.

CONCLUSION

The PSP detection rate differs among endoscopists. Longer withdrawal times are associated with better PSP detection, but patient features are not. (

CLINICAL TRIAL REGISTRATION NUMBER

NTR1888.).

Interobserver agreement among endoscopists on evaluation of polypoid colorectal lesions visualized with the Pentax i-Scan technique

BACKGROUND AND AIMS

Advances in colonoscopy, such as the Pentax i-Scan electronic technique, have the potential to improve the early detection of colorectal cancer. The aim of this multicentre study was to assess the interobserver agreement in the visualization of the surface and margins of colorectal polyps and in distinguishing neoplastic from non-neoplastic polyps.

PATIENTS AND METHODS

Eight expert endoscopists examined 400 mixed previously recorded images of polyps taken with different Pentax i-Scan settings in order to give an evaluation of the surface of the polyp and regular colonic mucosa, the pit-pattern and the nature of the lesion.

RESULTS

A total of 400 mixed images of polyps with a diameter >5mm and <10mm were stored for analysis. Overall, there was a Kf agreement of 0.370 (p<0.001) and 0.306 (p<0.001) regarding pit-pattern and margins, respectively. The Kf agreement for the difference between neoplastic and non-neoplastic lesions was of 0.446 (p<0.001).

CONCLUSIONS

We observed good interobserver agreement in the evaluation of neoplastic and non-neoplastic lesions and poor agreement in the evaluation of pit-pattern and margins. Adequate training is required in order to interpret images acquired with the i-Scan technique.

Endoscopic techniques for improving colorectal adenoma detection: Recent progress

Colorectal cancer (CRC) is one of the most common malignant neoplasms worldwide and develops mostly from precancerous lesions such as colorectal adenomas. Therefore, early detection and resection of colorectal adenomas is key to preventing CRC. At present, colonoscopy is acknowledged as the gold standard for the diagnosis and treatment of colorectal lesions; however, conventional colonoscopy is still associated with a certain rate of missed lesions. It is reported that the missed detection rate is 6% when adenomas are more than 1 cm, 13% for adenomas 6-9 mm, and 27% for adenomas less than 5 mm. The missed detection rate for right colonic adenomas is higher than that for left colonic adenomas. The missed diagnosis of colorectal adenomas or malignant tumors invariably increases surgical rate and mortality. Currently, great efforts have been made to improve the detection rate of colorectal adenomas. This paper will briefly review recent advances in endoscopic techniques for improving the detection rate of colorectal adenomas.

High-definition colonoscopy with i-Scan: Better diagnosis for small polyps and flat adenomas

AIM: To investigate if high-definition (HD) colonoscope with i-Scan gave a higher detection rate of mucosal lesions vs standard white-light instruments.

METHODS: Data were collected from the computerized database of the endoscopy unit of our tertiary referral center. We retrospectively analyzed 1101 consecutive colonoscopies that were performed over 1 year with standard white-light (n = 849) or HD+ with i-Scan (n = 252) instruments by four endoscopists, in an outpatient setting. Colonoscopy records included patients’ main details and family history for colorectal cancer, indication for colonoscopy (screening, diagnostic or surveillance), type of instrument used (standard white-light or HD+ plus i-Scan), name of endoscopist and bowel preparation. Records for each procedure included whether the cecum was reached or not and the reason for failure, complications during or immediately after the procedure, and number, size, location and characteristics of the lesions. Polyps or protruding lesions were defined as sessile or pedunculated, and nonprotruding lesions were defined according to Paris classification. For each lesion, histological diagnosis was recorded.

RESULTS: Eight hundred and forty-nine colonoscopies were carried with the standard white-light video colonoscope and 252 with the HD+ plus i-Scan video colonoscope. The four endoscopists did 264, 300, 276 and 261 procedures, respectively; 21.6%, 24.0%, 21.7% and 24.1% of them with the HD+ plus i-Scan technique. There were no significant differences between the four endoscopists in either the number of procedures done or the proportions of each imaging technique used. Both techniques detected one or more mucosal lesions in 522/1101 procedures (47.4%). The overall number of lesions recognized was 1266; 645 in the right colon and 621 in the left. A significantly higher number of colonoscopies recognized lesions in the HD+ plus i-Scan mode (171/252 = 67.9%) than with the standard white-light technique (408/849 = 48.1%) (P < 0.0001). HD+ with i-Scan colonoscopies identified more lesions than standard white-light imaging (459/252 and 807/849, P < 0.0001), in the right or left colon (mean ± SD, 1.62 ± 1.36 vs 1.33 ± 0.73, P < 0.003 and 1.55 ± 0.98 vs 1.17 ± 0.93, P = 0.033), more lesions < 10 mm (P < 0.0001) or nonprotruding (P < 0.022), and flat polyps (P = 0.04). The cumulative mean number of lesions per procedure detected by the four endoscopists was significantly higher with HD+ with i-Scan than with standard white-light imaging (1.82 ± 2.89 vs 0.95 ± 1.35, P < 0.0001).

CONCLUSION: HD imaging with i-Scan during the withdrawal phase of colonoscopy significantly increased the detection of colonic mucosal lesions, particularly small and nonprotruding polyps.

Water-aided colonoscopy: a systematic review

BACKGROUND

Water-aided methods for colonoscopy are distinguished by the timing of removal of infused water, predominantly during withdrawal (water immersion) or during insertion (water exchange).

OBJECTIVE

To discuss the impact of these approaches on colonoscopy pain and adenoma detection rate (ADR).

DESIGN

Systematic review.

SETTING

Randomized, controlled trial (RCT) that compared water-aided methods and air insufflation during colonoscope insertion.

PATIENTS

Patients undergoing colonoscopy.

INTERVENTION

Medline, PubMed, and Google searches (January 2008-December 2011) and personal communications of manuscripts in press were considered to identify appropriate RCTs.

MAIN OUTCOME MEASUREMENTS

Pain during colonoscopy and ADR. RCTs were grouped according to whether water immersion or water exchange was used. Reported pain scores and ADR were tabulated based on group assignment.

RESULTS

Pain during colonoscopy is significantly reduced by both water immersion and water exchange compared with traditional air insufflation. The reduction in pain scores was qualitatively greater with water exchange as compared with water immersion. A mixed pattern of increases and decreases in ADR was observed with water immersion. A higher ADR, especially proximal to the splenic flexure, was obtained when water exchange was implemented.

LIMITATIONS

Differences in the reports limit application of meta-analysis. The inability to blind the colonoscopists exposed the observations to uncertain bias.

CONCLUSION

Compared with air insufflation, both water immersion and water exchange significantly reduce colonoscopy pain. Water exchange may be superior to water immersion in minimizing colonoscopy discomfort and in increasing ADR. A head-to-head comparison of these 3 approaches is required.

Indigocarmine added to the water exchange method enhances adenoma detection - a RCT

PURPOSE

Chromoendoscopy with dye spray and the water method both increase adenoma detection.

HYPOTHESIS

Adding indigocarmine to the water method will enhance further the effectiveness of the latter in adenoma detection.

METHODS

Screening colonoscopy was performed with the water method (control) or with 0.008% indigocarmine added (study) by two endoscopists. Randomization was based on computer-generated codes contained in blocks of pre-arranged opaque sealed envelopes. High resolution colonoscopes were used. Upon insertion into the rectum, air was suctioned. With the air pump turned off, water was infused using a blunt needle adaptor connected to the scope channel and a foot pump to facilitate scope insertion until the cecum was reached. Residual stool causing cloudiness was suctioned followed by infusion of clear or colored water (water exchange) to facilitate scope passage with minimal distention of the colonic lumen. Upon seeing the appendix opening under water, water was suctioned and air was insufflated to facilitate inspection on scope withdrawal.

STATISTICS

Sample size calculation revealed 168 patients (84/group) needed to be randomized. Study was IRB-approved and registered (NCT01383265).

RESULTS

There were no significant differences in mean age, gender distribution, BMI, and family history of colon cancer. Cecal intubation success rate was 100% in both groups. The overall adenoma detection rate was 44% (water only) versus 62% (water with indigocarmine), respectively (p=0.03). One cancer was detected in each group.

CONCLUSION

In a RCT, indigocarmine at 0.008% concentration, added to the water method, significantly enhanced further the effectiveness of the latter in detecting adenomas.

Prevalence of missed adenomas in patients with inadequate bowel preparation on screening colonoscopy

BACKGROUND

The prevalence of missed polyps in patients with inadequate bowel preparation on screening colonoscopy is unknown.

OBJECTIVE

To determine the prevalence of missed adenomas in average-risk patients presenting for screening colonoscopy who are found to have inadequate bowel preparation.

DESIGN

Retrospective chart review. Endoscopy and pathology reports were examined to determine the characteristics of polyps. Data from repeat colonoscopies were collected through 2010.

SETTING

Outpatient endoscopy center at an academic medical center.

PATIENTS

This study involved patients who underwent outpatient average-risk screening colonoscopy between 2004 and 2009 documented to have inadequate bowel preparation and who had colonoscopy to the cecum.

MAIN OUTCOME MEASUREMENTS

Initial adenoma detection rate and adenoma detection rate on follow-up examination.

RESULTS

Inadequate bowel preparation was reported on 373 patients, with an initial adenoma detection rate of 25.7%. Of 133 patients who underwent repeat colonoscopy, 33.8% had at least 1 adenoma detected, and 18.0% had high-risk states detected (≥ 3 adenomas, 1 adenoma ≥ 1 cm, or any adenoma with villous features or high-grade dysplasia). Per-adenoma miss rate was 47.9%. Among patients with at least 1 adenoma on repeat colonoscopy, 31.1% had no polyps on initial colonoscopy; mean time between colonoscopies was 340 days. Among patients with high-risk states, 25.0% had no polyps seen on initial colonoscopy; mean time between colonoscopies was 271 days.

LIMITATIONS

Retrospective design.

CONCLUSION

Adenomas and high-risk lesions were frequently detected on repeat colonoscopy in patients with inadequate bowel preparation on initial screening colonoscopy, suggesting that these lesions were likely missed on initial colonoscopy.

Latest generation, wide-angle, high-definition colonoscopes increase adenoma detection rate

BACKGROUND & AIMS

Improvements to endoscopy imaging technologies might improve detection rates of colorectal cancer and patient outcomes. We compared the accuracy of the latest generation of endoscopes with older generation models in detection of colorectal adenomas.

METHODS

We compared data from 2 prospective screening colonoscopy studies (the Berlin Colonoscopy Project 6); each study lasted approximately 6 months and included the same 6 colonoscopists, who worked in private practice. Participants in group 1 (n = 1256) were all examined by using the latest generation of wide-angle, high-definition colonoscopes that were manufactured by the same company. Individuals in group 2 (n = 1400) were examined by endoscopists who used routine equipment (a mixture of endoscopes from different companies; none of those used to examine group 1). The adenoma detection rate was calculated on the basis of the number of all adenomas/number of all patients.

RESULTS

There were no differences in patient parameters or withdrawal time between groups (8.0 vs 8.2 minutes). The adenoma detection rate was significantly higher in group 1 (0.33) than in group 2 (0.27; P = .01); a greater number of patients with least 1 adenoma were identified in group 1 (22.1%) than in group 2 (18.2%; P = .01). A higher percentage of high-grade dysplastic adenomas were detected in group 1 (1.19%) than in group 2 (0.57%), but this difference was not statistically significant (P = .06).

CONCLUSIONS

The latest generation of wide-angle, high-definition colonoscopes improves rates of adenoma detection by 22%, compared with mixed, older technology endoscopes used in routine private practice. These findings might affect definitions of quality control parameters for colonoscopy screening for colorectal cancer.