Image-enhanced endoscopy technology in the gastrointestinal tract: what is available?

Prediction of adenoma recurrence after piecemeal endoscopic mucosal resection: interobserver agreement and utilization of the Sydney EMR recurrence tool

Background and aims: Piecemeal endoscopic mucosal resection (pEMR) allows resection of larger non-invasive colorectal lesions. Adenoma recurrence is an important limitation and occurs in ≤20%. The present study aimed to validate the Sydney EMR recurrence tool (SERT) score as a predictor of both endoscopic and histologic recurrence and evaluate interobserver agreement in adenoma recurrence based on endoscopic scar assessment, among nonexperts in EMR.Methods: Retrospective cohort and cross-sectional study, in which all patients submitted to pEMR in a tertiary care center in Portugal, between 2012 and 2018 were included. SERT-score was calculated for all lesions and compared with the SMSA (size, morphology, site, access) score already validated as a predictor of adenoma recurrence. Image based offline analysis was performed to evaluate adenoma recurrence prediction and assess the interobserver agreement within a heterogeneous group of participants, mostly composed by nonexperts in EMR.Results: There was a moderate positive correlation between the SERT and SMSA scores (p <.001; r = 0.61). SERT-score was significantly associated with endoscopic recurrence (p =.005) and histologic recurrence (p = .015). Endoscopic prediction of recurrence had high coefficient of agreement (k-0.806; p < .001).Conclusion: Histologic recurrence after pEMR can be predicted by SERT score and optical diagnosis of recurrent adenoma has high interobserver agreement between nonexperts in EMR.

Endoscopic scar assessment after colorectal endoscopic mucosal resection scars: when is biopsy necessary (EMR Scar Assessment Project for Endoscope (ESCAPE) trial)

OBJECTIVE

It is unclear whether endoscopic assessment of scars after colorectal endoscopic mucosal resection (EMR) has to include biopsies, even if endoscopy is negative. Vice versa, endoscopic diagnosis of recurrent adenoma may not require biopsy before endoscopic reinterventions. We prospectively analysed various endoscopic modalities in the diagnosis of recurrence following EMR.

DESIGN

We conducted a prospective study of patients undergoing colonoscopy after EMR of large (≥20 mm) colorectal neoplasia. Endoscopists predicted recurrence and confidence level with four imaging modes: high-definition white light (WL) and narrow-band imaging (NBI) with and without near focus (NF). Separately, 26 experienced endoscopists assessed offline images.

RESULTS

Two hundred and thirty patients with 255 EMR scars were included. The prevalence of recurrent adenoma was 24%. Diagnostic values were high for all modes (negative predictive value (NPV) ≥97%, positive predictive value (PPV) ≥81%, sensitivity ≥90%, specificity ≥93% and accuracy ≥93%). In high-confidence cases, NBI with NF had NPV of 100% (95% CI 98% to 100%) and sensitivity of 100% (95% CI 93% to 100%). Use of clips at initial EMR increased diagnostic inaccuracy (adjusted OR=1.68(95% CI 1.01 to 2.75)). In offline assessment, specificity was high for all imaging modes (mean: ≥93% (range: 55%-100%)), while sensitivity was significantly higher for NBI-NF (82%(72%-93%)%)) compared with WL (69%(38%-86%); p<0.001), WL-NF (68%(55%-83%); p<0.001) and NBI (71%(59%-90%); p<0.001).

CONCLUSION

Our study demonstrates very high sensitivity and accuracy for all four imaging modalities, especially NBI with NF, for diagnosis of recurrent neoplasia after EMR. Our data strongly suggest that in cases of high confidence negative optical diagnosis based on NBI-NF, no biopsy is needed to confirm absence of recurrence during colorectal EMR follow-up. A high confidence positive optical diagnosis can lead to immediate resection of any suspicious area. In all cases of low confidence, biopsy is still required.

TRIAL REGISTRATION NUMBER

NCT02668198.

In-vivo Barrett's esophagus digital pathology stage classification through feature enhancement of confocal laser endomicroscopy

Barrett's esophagus (BE) is a premalignant condition that has an increased risk to turn into esophageal adenocarcinoma. Classification and staging of the different changes (BE in particular) in the esophageal mucosa are challenging since they have a very similar appearance. Confocal laser endomicroscopy (CLE) is one of the newest endoscopy tools that is commonly used to identify the pathology type of the suspected area of the esophageal mucosa. However, it requires a well-trained physician to classify the image obtained from CLE. An automatic stage classification of esophageal mucosa is presented. The proposed model enhances the internal features of CLE images using an image filter that combines fractional integration with differentiation. Various features are then extracted on a multiscale level, to classify the mucosal tissue into one of its four types: normal squamous (NS), gastric metaplasia (GM), intestinal metaplasia (IM or BE), and neoplasia. These sets of features are used to train two conventional classifiers: support vector machine (SVM) and random forest. The proposed method was evaluated on a dataset of 96 patients with 557 images of different histopathology types. The SVM classifier achieved the best performance with 96.05% accuracy based on a leave-one-patient-out cross-validation. Additionally, the dataset was divided into 60% training and 40% testing; the model achieved an accuracy of 93.72% for the testing data using the SVM. The presented model showed superior performance when compared with four state-of-the-art methods. Accurate classification is essential for the intestinal metaplasia grade, which most likely develops into esophageal cancer. Not only does our method come to the aid of physicians for more accurate diagnosis by acting as a second opinion, but it also acts as a training method for junior physicians who need practice in using CLE. Consequently, this work contributes to an automatic classification that facilitates early intervention and decreases samples of required biopsy.

Recent advances in pediatric gastrointestinal endoscopy: an overview

Pediatric gastrointestinal endoscopy has become a fundamental component of health care for infants and children. New imaging technologies and creative extraluminal applications have brought exciting and clinically important benefits to pediatric gastrointestinal endoscopy. Areas covered: The impact of different new technologies in pediatric endoscopy and focused on improvements in mucosa visualization and the application of new noninvasive tools and procedures to avoid biopsies or surgery are reviewed. Expert commentary: Enhancement in mucosal visualization and reduction of anesthesia and biopsies are the main goals that guide the endoscopy development in pediatrics. The advent of newer imaging modalities has allowed clinicians to characterize and evaluate subtle mucosal lesions better, while advancements in current endoscopes have created the opportunity to monitor chronic conditions noninvasively. Continued expansion of these modalities seems certain, with increased utilization in pediatric gastroenterology.

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

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