High-definition and filter-aided colonoscopy

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.

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.

Diagnostic value of probe-based confocal laser endomicroscopy and high-definition virtual chromoendoscopy in early esophageal squamous neoplasia

BACKGROUND

Detection and differentiation of esophageal squamous neoplasia (ESN) are of value in improving patient outcomes. Probe-based confocal laser endomicroscopy (pCLE) can serve in targeted biopsies in the diagnosis of GI neoplasia. However, its performance in ESN has not yet been reported.

OBJECTIVE

To investigate the diagnostic value of pCLE for early ESN screened by high-definition virtual chromoendoscopy (I-Scan) and verified by Lugol chromoendoscopy and histopathology.

DESIGN

Prospective and noninferiority trial.

SETTING

Single center in China.

PATIENTS

Patients were enrolled who (1) previously had histologically verified early ESN or (2) were about to undergo screening endoscopy and were 50 to 80 years of age between February 2013 and February 2014.

INTERVENTIONS

The esophagus was investigated sequentially by white-light endoscopy, I-Scan, then pCLE and iodine chromoendoscopy. The results were interpreted and compared with histopathologic results.

MAIN OUTCOME MEASUREMENTS

Diagnostic characteristics of pCLE and I-Scan.

RESULTS

In total, 356 patients were enrolled. In all, 42 patients were histologically proven to have 47 neoplasias. The diagnostic value of pCLE for ESN during ongoing endoscopy has a sensitivity, specificity, and accuracy of 94.6%, 90.7%, and 92.3%, respectively. The interobserver and intraobserver agreement was good and excellent, with κ values of 0.699 and 0.895, respectively. The detection rate by using I-Scan and Lugol chromoendoscopy was 10.4% and 12.9%, respectively (P<.01 for noninferiority).

LIMITATIONS

Single center.

CONCLUSIONS

pCLE shows promise in diagnosing and differentiating ESN in vivo. The screening performance of I-Scan in the detection of ESN is noninferior to that of iodine chromoendoscopy.

Advances in diagnostic and therapeutic colonoscopy

PURPOSE OF REVIEW

We review current studies on endoscopic and technologic advances for the detection and treatment of colorectal neoplasia.

RECENT FINDINGS

Improvements in adenoma detection have been shown to be possible with the use of high definition white light as well as water-related methods such as water exchange. Use of cap assist colonoscopy, when combined with water-related methods, has recently been shown to also improve the detection of adenomas. Narrow band imaging and confocal laser endomicroscopy may have an advantage of offering endoscopists the ability to make an 'optical diagnosis' with the possibility of discarding nonadenomatous tissue. Furthermore, educational interventions aimed at improving adenoma detection may have lasting effects on endoscopists' adenoma detection rates. Lastly, endoscopic mucosal resection and endoscopic submucosal dissection are being applied for the treatment of large colorectal polyps, obviating the need for surgery in most instances. However, further studies are needed to establish the optimal methods for polyp resection.

SUMMARY

Advances in endoscopic technology are being shown to enhance the detection of early cancers and precancerous lesions. However, these tools may be supplementary to a high-quality colonoscopy using excellent techniques, factors that are now being implemented in training programs.

Real-time histology in colonoscopy

Gastrointestinal endoscopy had major technological improvements and novel technologies in recent years. High-definition endoscopy has permitted an increasingly detailed view of the mucosa during colonoscopy. Filter techniques that enhance analysis of vessel and surface structures. Autofluorescence imaging relies on functional imaging of tissue alterations. Endocytoscopy is an ultrahigh-contact microscopy procedure for cellular analysis of the epithelium. Endomicroscopy is an adaption of laser scanning microscopy for real-time intravital surface and subsurface microscopy during endoscopy. With these technologies, endoscopy has moved from prediction of histology based on morphologic patterns toward visualization of cellular and subcellular details, providing real-time histology.

Surveillance in inflammatory bowel disease: chromoendoscopy and digital mucosal enhancement

Patients with long-standing inflammatory bowel disease (IBD) have an increased risk of developing colorectal cancer. Performing periodic dysplasia screening and surveillance may diminish this risk. To date, chromoendoscopy is the only technique that has consistently yielded positive results in large, well-designed dysplasia-detection trials. Most major society guidelines endorse chromoendoscopy as an adjunct, accepted, or preferred dysplasia-detection tool. This review outlines the available endoscopic technologies for the detection of dysplasia in IBD, considers the evidence supporting their use, and assesses which modalities are ready for use in clinical practice.

i-Scan high-definition white light endoscopy and colorectal polyps: prediction of histology, interobserver and intraobserver agreement

PURPOSE

Aim of the study was the evaluation of high-definition white light (HDWL) i-Scan endoscopy for diagnostic prediction of histology, inter- and intraobserver agreement for colorectal polyps.

METHODS

In this prospective single-center cohort study, a skilled endoscopist, with HDWL i-Scan, predicted on real-time the histology of 150 polyps from 78 patients undergoing colonoscopy. Subsequently, four endoscopists, not involved in the collection of cases, predicted the polyps' histology (neoplastic vs nonneoplastic) and repeated the assessment after 6 months.

RESULTS

Real-time assessment of the lesions predicted a correct histology in 138/150 cases with a sensitivity, specificity, and accuracy of 95, 82, and 92 %, respectively. Sensitivity, specificity, and accuracy of post-acquisition evaluation were 87.7, 61.7, and 82.2 %, respectively. The κ values of inter- and intraobserver agreement of prediction of histology were 0.462 (0.373-0.537) and 0.657 (0.523-0.917). Among the subset of polyps (n = 82) with good/excellent quality image, sensitivity and accuracy of HDWL i-Scan improved (97 %, p = 0.003 and 94 %, p = 0.002, respectively) as well as κ value of interobserver agreement (0.699).

CONCLUSIONS

HDWL i-Scan technology helps for characterization of polyps of the colon with good accuracy even if it cannot replace, at the moment, the histopathological examination. Reproducibility among operators is supported by a moderate substantial interobserver and intraobserver agreement.

Advances in novel diagnostic endoscopic imaging techniques in inflammatory bowel disease

The description and grading of inflammation seen at endoscopic evaluation in inflammatory bowel disease (IBD) are based on conventional white light endoscopy in an era using normal definition endoscopes. The new generation of high-definition endoscopes with electronic filter technology provides an opportunity to visualize mucosal inflammation in more details. The application of these new technologies in IBD is in its infancy, but the added value is beginning to be appreciated. Both the assessment of dysplasia and the assessment of inflammation may gain from use of high-definition endoscopy with filter technology. In addition, the advent of confocal laser endomicroscopy provides an opportunity to explore real-time histology, thus (perhaps) redefining our understanding of pathogenesis and nature of inflammation in IBD. We review the potential of these techniques to transform diagnostic endoscopic assessment of inflammation and dysplasia.

Chromoendoscopy in inflammatory bowel disease

Chromoendoscopy with methylene blue or indigo carmine significantly increases the diagnostic yield of finding intraepithelial neoplasia in patients with longstanding colitis. The number needed to treat is 14 for panchromoendoscopy to identify 1 additional patient with dysplasia. Chromoendoscopy can greatly facilitate the identification of flat lesions harboring intraepithelial neoplasia. Chromoendoscopy can guide biopsies and clearly reduces the amount of biopsies that are needed per patient. Magnifying endoscopy or CLE are additional techniques, which can be used in conjunction with chromoendoscopy to further reduce the amount of biopsies and to further increase the diagnostic yield. Chromoendoscopy is an established clinical procedure and recommended by many gastroenterological societies for surveillance of patients with longstanding ulcerative colitis. Thus, intravital staining should be an essential part of the diagnostic armamentarium of every colonoscopist.

A morphologic analysis of sessile serrated polyps observed during routine colonoscopy (with video)

BACKGROUND

Proximal colorectal cancer may arise from sessile serrated polyps (SSPs), which are often inconspicuous during colonoscopy. The gross morphologic characteristics of SSPs have not been systematically described, and this omission may contribute to colonoscopists overlooking them.

OBJECTIVES

To analyze the gross morphologic characteristics of SSPs detected during routine colonoscopy.

DESIGN

Retrospective analysis of high-resolution endoscopic video clips depicting SSPs in situ.

SETTING

Outpatient gastroenterology practice.

PATIENTS

A total of 124 subjects undergoing surveillance or screening colonoscopy after split-dose bowel preparation.

INTERVENTIONS

Analysis of 158 SSPs performed by using validated descriptors.

MAIN OUTCOME MEASUREMENTS

The prevalence of morphologic characteristics related to polyp shape, color, and texture.

RESULTS

A total of 158 SSPs were studied. For 7 visual descriptors, a κ coefficient of ≥ 0.7 was achieved, indicating good to excellent intraobserver agreement. The most prevalent visual descriptors were the presence of a mucous cap (63.9%), rim of debris or bubbles (51.9%), alteration of the contour of a fold (37.3%), and interruption of the underlying mucosal vascular pattern (32.3%). The most common "sentinel signs" were the presence of a mucous cap and alteration of the contour of a mucosal fold (each 24.6%), rim of debris or bubbles (21.7%), and a dome-shaped protuberance (20.3%). When comparing SSPs with adenomatous polyps, the frequencies of 5 of 7 morphologic characteristics and the distribution of sentinel signs differed (P < .01).

LIMITATIONS

Single-site, retrospective analysis.

CONCLUSIONS

SSPs exhibit distinct, variable morphologic characteristics. Many do not display classic features such as a mucous cap. Enhanced appreciation of these morphologic characteristics may improve SSP detection and thereby colorectal cancer prevention.

New imaging techniques and opportunities in endoscopy

Gastrointestinal endoscopy is undergoing major improvements, which are driven by new available technologies and substantial refinements of optical features. In this Review, we summarize available and evolving imaging technologies that could influence the clinical algorithm of endoscopic diagnosis. Detection, characterization and confirmation are essential steps required for proper endoscopic diagnosis. Optical and nonoptical methods can help to improve each step; these improvements are likely to increase the detection rate of neoplasias and reduce unnecessary endoscopic treatments. Furthermore, functional and molecular imaging are emerging as new diagnostic tools that could provide an opportunity for personalized medicine, in which endoscopy will define disease outcome or predict the response to targeted therapy.

Evolving techniques in colonoscopy

PURPOSE OF REVIEW

This review summarizes recent clinical studies of colonoscopy technique and new technologies.

RECENT FINDINGS

Water immersion reduces pain and sedation doses in unsedated and lightly sedated colonoscopy. Cap-fitted colonoscopy makes insertion faster and improves detection of lesions behind folds, but the latter effect is operator-dependent. A single controlled trial showed improved detection with the Third Eye Retroscope, but the two arms of the study were not controlled for withdrawal time. Chromoendoscopy increases detection of diminutive adenomas, but adds time to the colonoscopy procedure. Electronic chromoendoscopy methods (narrow band imaging, Fujinon Intelligent ChromoEndoscopy, i-scan, and autofluorescence) have been either unsuccessful in improving detection or require more study. However, these methods and several other methods (chromoendoscopy with magnification, confocal laser microscopy, and endocytoscopy) allow accurate real time determination of polyp histology.

SUMMARY

Water immersion is a clear advance in unsedated colonoscopy. Cap-fitted colonoscopy is a promising method for both practical and effective visualization of the proximal sides of haustral folds. Electronic chromoendoscopy has been largely ineffective at improving polyp detection, but is effective (as are confocal laser microscopy and endocytoscopy) for diagnosis of polyp histology.

An unmet medical need: advances in endoscopic imaging of colorectal neoplasia

Gastrointestinal cancer is a major public health problem worldwide. Detection of early neoplastic lesions in gastrointestinal tract is essential for cure, because prognosis and survival are related to the size and stage of malignant lesions. Endoscopic screening and treatment of polyps could prevent approximately 80% of colorectal cancer (CRC). However, white-light endoscopy is an imperfect technology since miss rates of up to 25% have been reported and polyps without malignant potential were treated without benefit but with additional costs and risks to the patient. There are several known "human" predictors of an inadequate colonoscopy. These include patient characteristics such as poor bowel preparation, female gender, or inpatient status. Skills of the endoscopists are also an important issue. Therefore, a variety of advanced technologies has been attempted to overcome these issues. These new endoscopic imaging techniques allow a more precise classification of mucosal alterations with selection of patients for invasive therapy or surveillance. Further, molecular and functional imaging techniques could identify novel targets for therapies and new prospects to access response to therapies. However, at the "end of the day" a better endoscopic approach for CRC screening and surveillance depends on a good bowel preparation, a trained endoscopist spending sufficient time on a detailed examination together with an advanced endoscope.