Ultrathin endoscopy versus high-resolution endoscopy for diagnosing superficial gastric neoplasia

Image-enhanced endoscopy in the diagnosis of gastric premalignant conditions and gastric cancer

Diagnosis of early gastric cancer and its precancerous lesions remains a challenge for great part of western endoscopists. Changes seen in the mucosal pattern are generally subtle and hence difficult to identify. In this article, we will review the usefulness of conventional and virtual chromoendoscopy and magnification endoscopy in the recognition and classification of these lesions.

Visibility of early gastric cancers by texture and color enhancement imaging using a high-definition ultrathin transnasal endoscope

We evaluated whether texture and color enhancement imaging (TXI) using a high-definition ultrathin transnasal endoscope (UTE) improves the visibility of early gastric cancer (EGC) compared with white-light imaging (WLI). This study included 31 EGCs observed by TXI mode 2 using a high-definition UTE prior to endoscopic submucosal dissection. The first outcome was to compare the color differences based on Commission Internationale de l'Eclairage L*a*b* color space between EGCs and the surrounding mucosa by WLI and TXI using the UTE (objective appearance of EGC). The second outcome was to assess the visibility of EGCs by WLI and TXI using the UTE in an image evaluation test performed on 10 endoscopists (subjective appearance of EGC). Color differences between EGCs and non-neoplastic mucosa were significantly higher in TXI than in WLI in all EGCs (TXI: 16.0 ± 10.1 vs. WLI: 10.2 ± 5.5 [mean ± standard deviation], P < 0.001). Median visibility scores evaluated by 10 endoscopists using TXI were significantly higher than those evaluated using WLI (TXI: 4 [interquartile range, 4-4] vs. WLI: 4 [interquartile range, 3-4], P < 0.001). TXI using high-definition UTE improved both objective and subjective visibility of EGCs compared with WLI.

Third-Generation High-Vision Ultrathin Endoscopy Using Texture and Color Enhancement Imaging and Narrow-Band Imaging to Evaluate Barrett's Esophagus

It remains unclear whether texture- and color-enhancement imaging (TXI) and narrow-band imaging (NBI) provide an advantage over white-light imaging (WLI) in Barrett’s esophagus. We compared endoscopic findings and color differences between WLI and image-enhanced endoscopy (IEE) using a third-generation ultrathin endoscope. We retrospectively enrolled 40 patients who evaluated Barrett’s esophagus using WLI, TXI, and NBI. Color differences determined using the International Commission on Illumination 1976 (L∗, a∗, b∗) color space among Barrett’s epithelium, esophageal, and gastric mucosa were compared among the endoscopic findings. As the secondary outcome, we assessed the subjective visibility score among three kinds of endoscopic findings. The prevalence of Barrett’s esophagus and gastroesophageal reflux disease (GERD) in WLI was 82.5% and 47.5%, respectively, and similar among WLI, TXI, and NBI. Color differences between Barrett’s epithelium and esophageal or gastric mucosa on NBI were significantly greater than on WLI (all p < 0.05). However, the color difference between Barrett’s epithelium and esophageal mucosa was significantly greater on NBI than TXI (p < 0.001), and the visibility score of Barrett’s epithelium detection was significantly greater on TXI than NBI (p = 0.022), and WLI (p = 0.016). High-vision, third-generation ultrathin endoscopy using NBI and TXI is useful for evaluating Barrett’s epithelium and GERD compared with WLI alone.

Using texture and colour enhancement imaging to evaluate gastrointestinal diseases in clinical practice: a review

White light imaging (WLI) is the most common endoscopic technique used for screening of gastrointestinal diseases. However, despite the advent of a new processor that offers sufficient clear illumination and other advanced developments in endoscopic instrumentation, WLI alone is inadequate for detecting all gastrointestinal diseases with abnormalities in mucosal discoloration and morphological changes to the mucosal surface. The recent development of image-enhanced endoscopy (IEE) has dramatically improved the detection of gastrointestinal diseases. Texture and colour enhancement imaging (TXI) is a new type of IEE that enhances brightness, surface irregularities, such as elevations or depressions, and subtle colour changes. TXI with two modes, namely modes 1 and 2, can selectively enhance brightness in dark areas of an endoscopic image and subtle tissue differences such as slight morphological or colour changes while simultaneously preventing over-enhancement. Several clinical studies have investigated the efficacy of TXI for detecting and visualizing gastrointestinal diseases, including oesophageal squamous cell carcinoma (ESCC), Barret's epithelium, gastric cancer, gastric mucosal atrophy and intestinal metaplasia. Although TXI is often more useful for detecting and visualizing gastrointestinal diseases than WLI, it remains unclear whether TXI outperforms other IEEs, such as narrow-band imaging (NBI), in similar functions, and whether the performance of TXI modes 1 and 2 are comparable. Therefore, large-scale prospective studies are needed to compare the efficacy of TXI to WLI and other IEEs for endoscopic evaluation of patients undergoing screening endoscopy. Here, we review the characteristics and efficacy of TXI for the detection and visualization of gastrointestinal diseases.Key MessagesTXI mode 1 can improve the visibility of gastrointestinal diseases and qualitative diagnosis, especially for diseases associated with colour changes.The enhancement of texture and brightness with TXI mode 2 enables the detection of diseases, and is ideal for use in the first screening of gastrointestinal tract.

Efficacy of high-vision transnasal endoscopy using texture and colour enhancement imaging and narrow-band imaging to evaluate gastritis: a randomized controlled trial

BACKGROUND

A new image-enhanced endoscopy method called texture and colour enhancement imaging (TXI) enhances brightness, surface irregularities, and subtle colour changes in endoscopic images. However, it is unclear whether TXI and narrow-band imaging (NBI) with third-generation high-vision transnasal ultrathin endoscopy are advantageous over white-light imaging (WLI) for detecting atrophy, intestinal metaplasia, map-like redness and gastric cancer. We investigated to compare the endoscopic efficacy for evaluation of gastritis between TXI and NBI with high-vision transnasal endoscopy and clarified the endoscopic efficacy of TXI and NBI compared to WLI.

METHODS

We enrolled 60 patients who underwent high-vision transnasal endoscopy as part of a health check-up from March to November 2021 and randomized patients into two groups (the WLI-NBI group and the WLI-TXI group) using the minimization method based on Helicobacter pylori infection status, age and sex. Colour differences determined using the International Commission on Illumination 1976 (L∗, a∗, b∗) colour space was compared between WLI and TXI or NBI.

RESULTS

No significant differences were observed in colour differences surrounding atrophy, intestinal metaplasia and map-like redness between NBI and TXI (p = .553, .057 and .703, respectively). Endoscopic scores based on the Kyoto classification of gastritis for atrophy, intestinal metaplasia, and map-like redness were similar between WLI and TXI. In contrast, NBI identified intestinal metaplasia at a significantly greater rate than WLI (p = .018). Further, colour differences surrounding atrophy and intestinal metaplasia on TXI and NBI were significantly greater than those on WLI (atrophy: TXI vs WLI p = .003, NBI vs WLI p < .001; intestinal metaplasia: TXI vs WLI p = .016, NBI vs WLI p < .001). However, TXI and NBI were not advantageous over WLI for detecting map-like redness.

CONCLUSION

Third-generation high-vision transnasal ultrathin endoscopy using TXI and/or NBI is useful for detecting atrophic borders and intestinal metaplasia.Key MessagesHigh-vision transnasal endoscopy using TXI or NBI is useful for diagnosing and detecting atrophy and intestinal metaplasia.TXI and NBI increase colour differences surrounding atrophy and intestinal metaplasia, thereby increasing diagnostic efficiency to improve risk stratification for gastric cancer.The image quality and detection rate have improved markedly with the latest ultrathin high-vision transnasal endoscopes.

Present status and the future of ultrathin endoscopy

Endoscopic population-based screening for gastric cancer began in April 2016, and the use of transnasal ultrathin esophagogastroduodenoscopy (UT-EGD) has rapidly become popular. With UT-EGD, discomfort associated with an examination is reduced, patient satisfaction is high, and adverse effects on cardiopulmonary function are fewer. Consequently, UT-EGD is a good option for gastric screening in an aging society. Because of the narrower diameter of the endoscope, however, image quality is inferior to that obtained using transoral conventional esophagogastroduodenoscopy (C-EGD). As a result, lesions observed by UT-EGD must be viewed at close proximity and chromoendoscopy should be used concurrently, which is burdensome for the endoscopist. Recent innovations by endoscope manufacturers have enabled dramatic improvements in transnasal UT-EGD and facilitated Hi-Vision imaging. Furthermore, image enhancement that allows for observation on a par with transoral C-EGD is now feasible. In the future, UT-EGD will be equipped with functions that permit magnified endoscopic image. It is anticipated that a multiroute transition between transnasal and transoral UT-EGD will become possible.

Improved detection of early gastric cancer with linked color imaging using an ultrathin endoscope: a video-based analysis

Background and study aims  Ultrathin endoscopy causes a minimal gag reflex and has minimal effects on cardiopulmonary function. Linked color imaging (LCI) is useful for detection of malignancies in the digestive tract. The aim of this study was to clarify whether LCI with ultrathin endoscopy facilitates detection of early gastric cancer (EGC) despite its lower resolution compared with high-resolution white light imaging (WLI) with standard endoscopy. Patients and methods  This was a retrospective analysis with prospectively collected video, including consecutive 166 cases of EGC or gastric atrophy alone. Ninety seconds of screening video was collected using standard and ultrathin endoscopes with both WLI and LCI for each case. Three expert endoscopists assessed each video and the sensitivity of detecting EGC calculated. Color difference calculations were performed. Results  Sensitivities using ultrathin WLI, ultrathin LCI, standard WLI, and standard LCI for the identification of cancer were 66.0 %, 80.3 %, 69.9 %, and 84.0 %, respectively. The color difference between malignant lesions and surrounding mucosa with ultrathin LCI and standard LCI were significantly higher than using ultrathin WLI or standard WLI, supported subjectively by the visibility score. Ultrathin LCI color difference and visibility score were significantly higher than standard WLI. Conclusions  LCI with a low-resolution ultrathin endoscope is superior to WLI with a high-resolution standard endoscope for gastric cancer screening. This suggests that the high color contrast between EGC and the surrounding mucosa is more important than high-resolution images.

Convolutional neural network-based system for endocytoscopic diagnosis of early gastric cancer

Background

Endocytoscopy (ECS) aids early gastric cancer (EGC) diagnosis by visualization of cells. However, it is difficult for non-experts to accurately diagnose EGC using ECS. In this study, we developed and evaluated a convolutional neural network (CNN)-based system for ECS-aided EGC diagnosis.

Methods

We constructed a CNN based on a residual neural network with a training dataset comprising 906 images from 61 EGC cases and 717 images from 65 noncancerous gastric mucosa (NGM) cases. To evaluate diagnostic ability, we used an independent test dataset comprising 313 images from 39 EGC cases and 235 images from 33 NGM cases. The test dataset was further evaluated by three endoscopists, and their findings were compared with CNN-based results.

Results

The trained CNN required 7.0 s to analyze the test dataset. The area under the curve of the total ECS images was 0.93. The CNN produced 18 false positives from 7 NGM lesions and 74 false negatives from 28 EGC lesions. In the per-image analysis, the accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 83.2%, 76.4%, 92.3%, 93.0%, and 74.6%, respectively, with the CNN and 76.8%, 73.4%, 81.3%, 83.9%, and 69.6%, respectively, for the endoscopist-derived values. The CNN-based findings had significantly higher specificity than the findings determined by all endoscopists. In the per-lesion analysis, the accuracy, sensitivity, specificity, PPV, and NPV of the CNN-based findings were 86.1%, 82.1%, 90.9%, 91.4%, and 81.1%, respectively, and those of the results calculated by the endoscopists were 82.4%, 79.5%, 85.9%, 86.9%, and 78.0%, respectively.

Conclusions

Compared with three endoscopists, our CNN for ECS demonstrated higher specificity for EGC diagnosis. Using the CNN in ECS-based EGC diagnosis may improve the diagnostic performance of endoscopists.

Efficacy of a Third-Generation High-Vision Ultrathin Endoscope for Evaluating Gastric Atrophy and Intestinal Metaplasia in Helicobacter pylori-Eradicated Patients

BACKGROUND

Image-enhanced endoscopy methods such as narrow-band imaging (NBI) are advantageous over white-light imaging (WLI) for detecting gastric atrophy, intestinal metaplasia, and cancer. Although new third-generation high-vision ultrathin endoscopes improve image quality and resolution over second-generation endoscopes, it is unclear whether the former also enhances color differences surrounding atrophy and intestinal metaplasia for endoscopic detection. We compared the efficacy of a new third-generation ultrathin endoscope and an older second-generation endoscope.

METHODS

We enrolled 50 Helicobacter pylori-eradicated patients who underwent transnasal endoscopy with a second-generation and third-generation endoscope (GIF-290N and GIF-1200N, respectively) in our retrospective study. Color differences based on the International Commission on Illumination 1976 (L*, a*, b*) color space were compared between second-generation and third-generation high-vision endoscopes.

RESULTS

Color differences surrounding atrophy produced by NBI on the GIF-1200N endoscope were significantly greater than those on GIF-290N (19.2 ± 8.5 vs. 14.4 ± 6.2, p = 0.001). In contrast, color differences surrounding intestinal metaplasia using both WLI and NBI were similar on GIF-1200N and GIF-290N endoscopes. NBI was advantageous over WLI for detecting intestinal metaplasia on both endoscopes.

CONCLUSIONS

NBI using a third-generation ultrathin endoscope produced significantly greater color differences surrounding atrophy and intestinal metaplasia in H. pylori-eradicated patients compared with WLI.

Identification of gastric cancer with convolutional neural networks: a systematic review

The identification of diseases is inseparable from artificial intelligence. As an important branch of artificial intelligence, convolutional neural networks play an important role in the identification of gastric cancer. We conducted a systematic review to summarize the current applications of convolutional neural networks in the gastric cancer identification. The original articles published in Embase, Cochrane Library, PubMed and Web of Science database were systematically retrieved according to relevant keywords. Data were extracted from published papers. A total of 27 articles were retrieved for the identification of gastric cancer using medical images. Among them, 19 articles were applied in endoscopic images and 8 articles were applied in pathological images. 16 studies explored the performance of gastric cancer detection, 7 studies explored the performance of gastric cancer classification, 2 studies reported the performance of gastric cancer segmentation and 2 studies analyzed the performance of gastric cancer delineating margins. The convolutional neural network structures involved in the research included AlexNet, ResNet, VGG, Inception, DenseNet and Deeplab, etc. The accuracy of studies was 77.3 - 98.7%. Good performances of the systems based on convolutional neural networks have been showed in the identification of gastric cancer. Artificial intelligence is expected to provide more accurate information and efficient judgments for doctors to diagnose diseases in clinical work.

Unsedated Transnasal Endoscopy: A Safe, Well-Tolerated and Accurate Alternative to Standard Diagnostic Peroral Endoscopy

Diagnostic unsedated transnasal endoscopy (uTNE) has been proven to be a safe and well-tolerated procedure. Although its utilization in the United Kingdom (UK) is increasing, it is currently available in only a few centers. Through consideration of recent studies, we aimed to perform an updated review of the technological advances in uTNE, consider their impact on diagnostic accuracy, and to determine the role of uTNE in the COVID-19 era. Current literature has shown that the diagnostic accuracy of uTNE for identification of esophageal pathology is equivalent to conventional esophagogastroduodenoscopy (cEGD). Concerns regarding suction and biopsy size have been addressed by the introduction of TNE scopes with working channels of 2.4 mm. Advances in imaging have improved detection of early gastric cancers. The procedure is associated with less cardiac stress and reduced aerosol production; when combined with no need for sedation and improved rates of patient turnover, uTNE is an efficient and safe alternative to cEGD in the COVID-19 era. We conclude that advances in technology have improved the diagnostic accuracy of uTNE to the point where it could be considered the first line diagnostic endoscopic investigation in the majority of patients. It could also play a central role in the recovery of diagnostic endoscopic services during the COVID-19 pandemic.

Automated Detection of Gastric Cancer by Retrospective Endoscopic Image Dataset Using U-Net R-CNN

Upper gastrointestinal endoscopy is widely performed to detect early gastric cancers. As an automated detection method for early gastric cancer from endoscopic images, a method involving an object detection model, which is a deep learning technique, was proposed. However, there were challenges regarding the reduction in false positives in the detected results. In this study, we proposed a novel object detection model, U-Net R-CNN, based on a semantic segmentation technique that extracts target objects by performing a local analysis of the images. U-Net was introduced as a semantic segmentation method to detect early candidates for gastric cancer. These candidates were classified as gastric cancer cases or false positives based on box classification using a convolutional neural network. In the experiments, the detection performance was evaluated via the 5-fold cross-validation method using 1208 images of healthy subjects and 533 images of gastric cancer patients. When DenseNet169 was used as the convolutional neural network for box classification, the detection sensitivity and the number of false positives evaluated on a lesion basis were 98% and 0.01 per image, respectively, which improved the detection performance compared to the previous method. These results indicate that the proposed method will be useful for the automated detection of early gastric cancer from endoscopic images.

Characteristics of superficial esophageal squamous cell carcinomas undetectable with narrow-band imaging endoscopy

Background

The detection rate of narrow-band imaging (NBI) for superficial esophageal squamous cell carcinoma (SESCC), including high-grade intraepithelial neoplasia, is significantly higher than that of white-light endoscopy. However, there are SESCCs that are undetectable by NBI but detectable by Lugol chromoendoscopy (LCE) and the characteristics of these SESCCs are still unknown. Thus, this study aimed to clarify the characteristics of SESCC that are undetectable using NBI.

Methods

Patients with current SCC or a history of SCC in the head and neck or in the esophagus were enrolled. The inspection of the esophagus was initiated by NBI, followed by LCE. Biopsies were taken of all suspected SESCC lesions during NBI observation and Lugol-voiding lesions (LVLs) that were irregularly shaped and >5 mm and/or pink in color during LCE observation. The characteristics of SESCC that were undetectable with NBI were statistically analysed.

Results

Overall, 147 lesions in 105 cases were histologically diagnosed as SESCC. Twenty in 15 cases were NBI-undetectable lesions, all of which were macroscopic flat type (0-IIb). The median sizes of the NBI-undetectable lesions and NBI-detectable lesions were both 15 mm (P = 0.47). Multivariate analysis revealed independent factors for NBI-undetectable lesions such as numerous irregularly shaped LVLs (odds ratio [OR]: 4.94, 95% confidence interval [CI]: 1.39–17.5, P < 0.05) and anterior wall position (OR: 4.99, 95% CI: 1.58–15.8, P < 0.05).

Conclusions

The detection of SESCCs with NBI is challenging when lesions are morphologically completely flat, in cases with numerous irregularly shaped LVLs, and if located at the anterior wall.

Advances in optical gastrointestinal endoscopy: a technical review

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

Three-dimensional flexible endoscopy enables more accurate endoscopic recognition and endoscopic submucosal dissection marking for superficial gastric neoplasia: a pilot study to compare two- and three-dimensional imaging

BACKGROUND

Three-dimensional (3D) visualization offers better depth recognition than two-dimensional (2D) imaging, thus helping to provide more useful information. We compared 3D and 2D endoscopy with regard to endoscopic recognition and endoscopic submucosal dissection (ESD) marking for superficial gastric neoplasia.

METHODS

ESD marking was performed on half of a neoplasia margin under 2D observation and the on other half under 3D observation for 28 gastric lesions (26 early gastric cancers and 2 adenomas). The accuracy of ESD marking was evaluated based on the distance between the pathological and endoscopic neoplasia margins measured on histology sections of ESD specimens. The technical ease of ESD marking and endoscopic lesion recognition (lesion morphology, lesion extent, and comprehensive endoscopic cognition) were assessed using visual analog scale (VAS) questionnaires.

RESULTS

The mean distance between the pathological and endoscopic margins under 3D observation (1.03 ± 0.80 mm) was significantly (p = 0.002) shorter than that under 2D observation (1.94 ± 1.96 mm). The VAS for technical ease of ESD marking under 3D observation was significantly better (p < 0.01) than that under 2D observation. The VAS for all aspects of endoscopic recognition under 3D observation was significantly better (p < 0.01) than under 2D observation.

CONCLUSIONS

3D flexible endoscopy achieved more accurate endoscopic recognition and ESD marking for superficial gastric neoplasia than a 2D approach in a clinical setting of ESD.

Automated Detection and Segmentation of Early Gastric Cancer from Endoscopic Images Using Mask R-CNN

Gastrointestinal endoscopy is widely conducted for the early detection of gastric cancer. However, it is often difficult to detect early gastric cancer lesions and accurately evaluate the invasive regions. Our study aimed to develop a detection and segmentation method for early gastric cancer regions from gastrointestinal endoscopic images. In this method, we first collected 1208 healthy and 533 cancer images. The gastric cancer region was detected and segmented from endoscopic images using Mask R-CNN, an instance segmentation method. An endoscopic image was provided to the Mask R-CNN, and a bounding box and a label image of the gastric cancer region were obtained. As a performance evaluation via five-fold cross-validation, sensitivity and false positives (FPs) per image were 96.0% and 0.10 FP/image, respectively. In the evaluation of segmentation of the gastric cancer region, the average Dice index was 71%. These results indicate that our proposed scheme may be useful for the detection of gastric cancer and evaluation of the invasive region in gastrointestinal endoscopy.

Comparing blind spots of unsedated ultrafine, sedated, and unsedated conventional gastroscopy with and without artificial intelligence: a prospective, single-blind, 3-parallel-group, randomized, single-center trial

BACKGROUND AND AIMS

EGD is the most vital procedure for the diagnosis of upper GI lesions. We aimed to compare the performance of unsedated ultrathin transoral endoscopy (U-TOE), unsedated conventional EGD (C-EGD), and sedated C-EGD with or without the use of an artificial intelligence (AI) system.

METHODS

In this prospective, single-blind, 3-parallel-group, randomized, single-center trial, 437 patients scheduled to undergo outpatient EGD were randomized to unsedated U-TOE, unsedated C-EGD, or sedated C-EGD, and each group was then divided into 2 subgroups: with or without the assistance of an AI system to monitor blind spots during EGD. The primary outcome was the blind spot rate of these 3 groups with the assistance of AI. The secondary outcomes were to compare blind spot rates of unsedated U-TOE, unsedated, and sedated C-EGD with or without the assistance of AI, respectively, and the concordance between AI and the endoscopists' review.

RESULTS

The blind spot rate with AI-assisted sedated C-EGD was significantly lower than that of unsedated U-TOE and unsedated C-EGD (3.42% vs 21.77% vs 31.23%, respectively; P < .05). The blind spot rate of the AI subgroup was lower than that of the control subgroup in all 3 groups (sedated C-EGD: 3.42% vs 22.46%, P < .001; unsedated U-TOE: 21.77% vs 29.92%, P < .001; unsedated C-EGD: 31.23% vs 42.46%, P < .001).

CONCLUSIONS

The blind spot rate of sedated C-EGD was the lowest among the 3 types of EGD, and the addition of AI had a maximal effect on sedated C-EGD. (Clinical trial registration number: ChiCTR1900020920.).

Miniature gastrointestinal endoscopy: Now and the future

Since its original application, gastrointestinal (GI) endoscopy has undergone many innovative transformations aimed at expanding the scope, safety, accuracy, acceptability and cost-effectiveness of this area of clinical practice. One method of achieving this has been to reduce the caliber of endoscopic devices. We propose the collective term “Miniature GI Endoscopy”. In this Opinion Review, the innovations in this field are explored and discussed. The progress and clinical use of the three main areas of miniature GI endoscopy (ultrathin endoscopy, wireless endoscopy and scanning fiber endoscopy) are described. The opportunities presented by these technologies are set out in a clinical context, as are their current limitations. Many of the positive aspects of miniature endoscopy are clear, in that smaller devices provide access to potentially all of the alimentary canal, while conferring high patient acceptability. This must be balanced with the costs of new technologies and recognition of device specific challenges. Perspectives on future application are also considered and the efforts being made to bring new innovations to a clinical platform are outlined. Current devices demonstrate that miniature GI endoscopy has a valuable place in investigation of symptoms, therapeutic intervention and screening. Newer technologies give promise that the potential for enhancing the investigation and management of GI complaints is significant.

Endoscopic submucosal dissection (ESD) versus transanal endoscopic microsurgery (TEM) for treatment of rectal tumors: a comparative systematic review and meta-analysis

BACKGROUND

While multiple studies have evaluated endoscopic submucosal dissection (ESD) and transanal endoscopic microsurgery (TEM) to remove large rectal tumors, there remains a paucity of data to evaluate their comparative efficacy and safety. The primary aim of this study was to perform a structured systematic review and meta-analysis to compare efficacy and safety of ESD versus TEM for the treatment of rectal tumors.

METHODS

Individualized search strategies were developed from inception through November 2018 in accordance with PRISMA guidelines. Measured outcomes included pooled enbloc resection rates, margin-negative (R₀) resection rates, procedure-associated adverse events, and rates of recurrence. This was a cumulative meta-analysis performed by calculating pooled proportions. Heterogeneity was assessed with Cochran Q test and I² statistics, and publication bias by funnel plot using Egger and Begg tests.

RESULTS

Three studies (n = 158 patients; 55.22% male) were included in this meta-analysis. Patients with ESD compared to TEM had similar age (P = 0.090), rectal tumor size (P = 0.108), and diagnosis rate of adenoma to cancer (P = 0.53). ESD lesions were more proximal as compared to TEM (8.41 ± 3.49 vs. 5.11 ± 1.43 cm from the anal verge; P < 0.001). Procedure time and hospital stay were shorter for ESD compared to TEM [(79.78 ± 24.45 vs. 116.61 ± 19.35 min; P < 0.001) and (3.99 ± 0.32 vs. 5.83 ± 0.94 days; P < 0.001), respectively]. No significant differences between enbloc resection rates [OR 0.98 (95% CI 0.22-4.33); P = 0.98; I² = 0.00%] and R₀ resection rates [OR 1.16 (95% CI 0.36-3.76); P = 0.80; I² = 0.00%] were noted between ESD and TEM. ESD and TEM reported similar rates of adverse events [OR 1.15 (95% CI 0.47-2.77); P = 0.80; I² = 0.00%] and rates of recurrence [OR 0.46 (95% CI 0.07-3.14); P = 0.43; I² = 0.00%].

CONCLUSION

ESD and TEM possess similar rates of resection, adverse events, and recurrence for patients with large rectal tumors; however, ESD is associated with significantly shorter procedure times and duration of hospitalization. Future studies are needed to evaluate healthcare utilization for these two strategies.

The utility of ultrathin endoscopy with flexible spectral imaging color enhancement for early gastric cancer

Many researchers suggested that ultrathin endoscopy improves patient acceptance of endoscopic examinations. However, ultrathin endoscopy provides less image resolution and luminous intensity. Therefore, we focused on the visibility of early gastric cancer on ultrathin endoscopy with Flexible spectral imaging color enhancement (FICE) in this study. Thirty-six patients with early gastric cancer were prospectively enrolled. One endoscopist performed the endoscopic examinations by white light conventional endoscopy (W-CE), white light ultrathin endoscopy (W-UE), FICE ultrathin endoscopy (F-UE) and white light plus FICE ultrathin endoscopy (WF-UE) in the patients. Four other endoscopists were asked to evaluate the visibility of gastric cancer on the W-CE, W-UE, F-UE and WF-UE images with a 5-point Likert scale. The lesions were classified as uncolored, normocolored or reddish. We examined the color difference between early gastric cancer and the surrounding mucosa. To examine the relationship between the color difference and the vessel density, we also measured the difference in vessel density using pathologic specimens stained with hematoxylin and eosin. The Likert score of WF-UE was significantly higher than those of the other three methods (p<0.001). The color difference of F-UE was higher than that of W-CE in the reddish group (p=0.049). The difference in vessel density was higher in the reddish group than in the normocolored group (p=0.048). In conclusion, the visibility of early gastric cancer from the surrounding mucosa using ultrathin endoscopy with FICE was better than that using white light conventional endoscopy, especially for reddish lesions.

Comparison of efficacy and safety between endoscopic submucosal dissection and transanal endoscopic microsurgery for the treatment of rectal tumor

BACKGROUND/AIM

To compare the treatment efficacy and safety between endoscopic submucosal dissection (ESD) and transanal endoscopic microsurgery (TEM) for the treatment of rectal epithelial tumors, including large adenoma, cancer, and subepithelial tumors (SET).

PATIENTS AND METHODS

We conducted a retrospective analysis of the medical records of 71 patients with rectal tumors who were treated with ESD (48 patients) or TEM (23 patients) from January 2013 to December 2015. The patient group comprised 56 patients with epithelial tumors and 15 patients with SET. Treatment efficacy such as en bloc resection, procedure time, local recurrence, hospital stay, additional procedure rate, and safety between the treatment groups were evaluated and analyzed.

RESULTS

There were no significant differences in tumor size, location, macroscopic appearance, and histological depth between ESD and TEM groups. For ESD compared to TEM in rectal epithelial tumors, en bloc resection rates were 95% vs. 93.7% and R0 resection rates were 92.5% vs. 87.5% (P = 0.617); in rectal SET, en bloc resection rates were 100% vs. 100% and R0 resection rates were 87% vs. 85% (P = 0.91). The procedure time was 71.5 ± 51.3 min vs. 105.6 ± 28.2 min (P = 0.016) for epithelial tumors and 32.13 ± 13.4 min vs. 80.71 ± 18.35 min (P = 0.00) for SET, respectively. Hospital stay was 4.3 ± 1.2 days vs. 5.8 ± 1.8 days (P = 0.001) for epithelial tumors and 4.1 ± 4.1 days vs. 5.5 ± 2 days (P = 0.42) for rectal SET, respectively. There were no significant differences between recurrence rates, additional procedure rates, and complications in the two groups.

CONCLUSIONS

ESD and TEM are both effective and safe for the treatment of rectal epithelial tumors and SET because of favorable R0 resection rates and recurrence rates. However, the ESD group showed shorter procedure times and hospital stays than the TEM group. Therefore, ESD should be considered more preferentially than TEM in the treatment of large rectal epithelial tumors and SET.

Past and current trends in endoscopic diagnosis for early stage gastric cancer in Japan

Methodology for the diagnosis and staging of early gastric cancer (EGC) has improved in Japan since the development of the gastro-camera and determination of a definition of EGC. Imaging technology has been steadily evolving in the endoscopy field. Improvements in the resolution of standard endoscopy images used in screening and surveillance provide greater opportunities to find gastric cancer earlier. Image enhancement endoscopy (IEE), such as narrow band imaging (NBI), highlights mucosal structures and vascularity. In particular, when NBI is used with magnifying endoscopy, it reveals fine details of subtle superficial abnormalities of EGC that are difficult to recognize using standard white light endoscopy. IEE-assisted magnifying endoscopy has improved the accuracy of the differentiation of superficial gastric cancer as well as delineation of the diseased mucosa. The advanced imaging technology enables precise assessment of the risk of lymph node metastasis of EGC and is widely used to determine indications for endoscopic treatment. It is not an overstatement to say that this has become the basis for the current development and dissemination of endoscopic treatments. Moreover, the resolution of endoscopic imaging has been upgraded to the microscopy level by the development of endomicroscopy, including endocytoscopy and confocal laser endomicroscopy. Endomicroscopy allows real-time histological analysis of living tissue during routine endoscopy and may reduce the number of biopsies needed to reach the correct diagnosis, minimizing the risk of sampling errors.

Effectiveness of systematic alphanumeric coded endoscopy for diagnosis of gastric intraepithelial neoplasia in a low socioeconomic population

Background and study aims: In the Western world, gastric cancer (GC) usually presents at an advanced stage, carrying a high mortality rate. Studies have reported that 14 % to 26 % of GCs are missed at endoscopy up to 3 years before diagnosis. Systematic Alphanumeric Coded Endoscopy (SACE) has been proposed to improve quality of esophagogastroduodenoscopy (EGD) by facilitating a complete examination of the upper gastrointestinal tract. This prospective cross-sectional study was designed to determine the frequency of gastric intraepithelial neoplasia (GIN) by using the SACE approach in cohort of patients from low socioeconomic level. It also used non-targeted biopsies to evaluate the frequency of premalignant conditions. Patients and methods: A total of 601 consecutive asymptomatic or dyspeptic patients were enrolled between January 2013 and November 2014 at the Huacho regional hospital in Peru. The SACE method proposed by Emura et al, which divides the stomach into 5 regions and 21 areas, was routinely used for diagnosis. Biopsy samples were obtained from any endoscopically detected focal lesion. To evaluate gastric premalignant conditions, 4 non-targeted biopsies were taken. Results: A total of 573 patients were analyzed. The mean age was 57 years, and the female:male ratio was 1.9 : 1. In all cases, complete photo-documentation of the 21 gastric areas was achieved. The overall rate of detection of GIN was 2.8 %. Low-grade displasia, high-grade dysplasia, and adenocarcinoma were found in 13 (2.3 %), 2 (0.3 %), and 1 (0.2 %) of the patients, respectively. The prevalence of at least 1 premalignant condition was 31 %, and helicobacter pylori infection was found in 57 % of patients. Conclusions: Using the SACE approach and with proper training, we have reported herein a high frequency of GIN in patients from a low socioeconomic status. Gastric cancer detection can be improved in a Western endoscopy setting when SACE, as a screening method, is performed by a trained endoscopist.

Transnasal endoscopy: no gagging no panic!

BACKGROUND

Transnasal endoscopy (TNE) is performed with an ultrathin scope via the nasal passages and is increasingly used. This review covers the technical characteristics, tolerability, safety and acceptability of TNE and also diagnostic accuracy, use as a screening tool and therapeutic applications. It includes practical advice from an ear, nose, throat (ENT) specialist to optimise TNE practice, identify ENT pathology and manage complications.

METHODS

A Medline search was performed using the terms "transnasal", "ultrathin", "small calibre", "endoscopy", "EGD" to identify relevant literature.

RESULTS

There is increasing evidence that TNE is better tolerated than standard endoscopy as measured using visual analogue scales, and the main area of discomfort is nasal during insertion of the TN endoscope, which seems remediable with adequate topical anaesthesia. The diagnostic yield has been found to be similar for detection of Barrett's oesophagus, gastric cancer and GORD-associated diseases. There are some potential issues regarding the accuracy of TNE in detecting small early gastric malignant lesions, especially those in the proximal stomach. TNE is feasible and safe in a primary care population and is ideal for screening for upper gastrointestinal pathology. It has an advantage as a diagnostic tool in the elderly and those with multiple comorbidities due to fewer adverse effects on the cardiovascular system. It has significant advantages for therapeutic procedures, especially negotiating upper oesophageal strictures and insertion of nasoenteric feeding tubes.

CONCLUSIONS

TNE is well tolerated and a valuable diagnostic tool. Further evidence is required to establish its accuracy for the diagnosis of early and small gastric malignancies. There is an emerging role for TNE in therapeutic endoscopy, which needs further study.

Current status of transnasal endoscopy worldwide using ultrathin videoscope for upper gastrointestinal tract

Transnasal endoscopy with an ultrathin endoscope has been reported to be highly acceptable even without any sedative measures. Poor image quality and complex manipulation have been reported as shortcomings of this type of endoscopy compared with standard transoral endoscopy. However, image quality has improved markedly with the latest ultrathin endoscopes. To investigate the status of clinical use of endoscopes, we recently conducted a questionnaire survey involving 149 facilities (98 in Japan and 51 overseas). In Japan, transnasal endoscopes were being used primarily in clinics (34% in clinics and 9% in hospitals). Overseas, however, transnasal endoscopes were seldom used (1% in hospitals and 0% in clinics). This may be attributable to the complex pretreatment and more challenging manipulation required for transnasal endoscopes. However, it is evident that transnasal endoscopes are highly acceptable for patients. If the pretreatment required is simplified and healthcare physicians improve their skills and understanding, this type of endoscopy will have high potential for common use.

Endoscopic submucosal dissection

ESD is an established effective treatment modality for premalignant and early-stage malignant lesions of the stomach, esophagus, and colorectum. Compared with EMR, ESD is generally associated with higher rates of en bloc, R0, and curative resections and a lower rate of local recurrence. Oncologic outcomes with ESD compare favorably with competing surgical interventions, and ESD also serves as an excellent T-staging tool to identify noncurative resections that will require further treatment. ESD is technically demanding and has a higher rate of adverse events than most endoscopic procedures including EMR. As such,sufficient training is critical to ensure safe conduct and high-quality resections. A standardized training model for Western endoscopists has not been clearly established,but will be self-directed and include courses, animal model training, and optimally an observership at an expert center.Numerous dedicated ESD devices are now available in the United States from different manufacturers. Although the use of ESD in the United States is increasing, issues related to technical difficulty, limited training opportunities and mentors, risk of adverse events, long procedure duration,and suboptimal reimbursement may limit ESD adoption in the United States to a modest number of academic referral centers for the foreseeable future.

Performance characteristics of unsedated ultrathin video endoscopy in the assessment of the upper GI tract: systematic review and meta-analysis

BACKGROUND AND AIMS

Reports on the performance of unsedated ultrathin endoscopy via the transnasal (uTNE) and transoral (uTOE) routes are conflicting. We aimed to estimate the technical success rate, patient preference, and acceptability of uTNE and uTOE alone and in comparison with conventional EGD (cEGD; with or without sedation).

METHODS

A systematic review and meta-analysis was performed on all primary studies reporting the outcomes of interest. Electronic databases (Cochrane library, MEDLINE, EMBASE) were searched on February 1, 2014.

RESULTS

Thirty-four studies met the inclusion criteria with 6659 patients in total. The pooled technical success rate was 94.0% for uTNE (95% confidence interval [CI], 91.6-95.8; 30 studies) and 97.8% for uTOE (95% CI, 95.6-98.9; 16 studies). The difference in proportion of success for uTNE compared with cEGD was -2.0% (95% CI, -4.0 to -1.0; 18 studies), but that difference was not significant when uTNE < 5.9 mm in diameter was used (-1.0%; 95% CI, -3.0 to .0; 9 studies). There was no significant difference in success rate between uTOE and cEGD (.0%; 95% CI, -1.0 to 2.0; 10 studies). The pooled difference in proportion of patients who preferred uTNE over cEGD was 63.0% (95% CI, 49.0-76.0; 10 studies), whereas preference for uTOE versus cEGD was not significantly different (38.0%; 95% CI, -4.0 to 80.0; 2 studies). Acceptability was high for both uTNE (85.2%; 95% CI, 79.1-89.9; 16 studies) and uTOE (88.7%; 95% CI, 82.4-92.9; 10 studies).

CONCLUSIONS

Technical success rate for uTNE < 5.9 mm is equivalent to cEGD. uTNE has high patient acceptability, with better patient preference, and therefore could be a useful alternative to cEGD for screening purposes. uTOE had a similar technical success rate but an equivocal preference to cEGD.

Advanced endoscopic imaging for early gastric cancer

Considerable numbers of early gastric cancers can be missed or misdiagnosed with conventional white light imaging endoscopy (WLI), thus advanced endoscopic imaging modalities have been applied to overcome the issue. High definition endoscopy can improve diagnostic accuracy, but still misses 20-25% of early gastric cancer. Magnifying endoscopy combined with narrow band imaging (NBI) allows for very high accuracy, with sensitivity and specificity of over 95%. The algorithm for magnifying endoscopy diagnosis of gastric cancer is composed of 1) presence of demarcation line, and 2) presence of irregular microsurface and/or microvascular pattern. Ultra-high magnification of 400 times with endocytoscopy (ECS) can produce images reflecting structural and cellular atypia. Using high grade ECS atypia as the diagnostic criteria for gastric cancer, ECS achieves a high diagnostic accuracy (86% of sensitivity, 100% of specificity) although approximately 10% of target lesions are not assessable because of poor dye staining.

Evaluation of gastric cancer diagnosis using new ultrathin transnasal endoscopy with narrow-band imaging: preliminary study

BACKGROUND AND AIM

The new developed ultrathin transnasal endoscope, the GIF-XP290N, makes possible a resolving power similar to the GIF-H260 at a distance of 3 mm. In this study, using the GIF-XP290N, we evaluated whether endoscopic diagnosis (discrimination between benign and malignant) of gastric lesions is possible using nonmagnified narrow-band imaging (NBI) endoscopy.

METHODS

The subjects were 255 consecutive patients who underwent screening of the gastrointestinal tract using new ultrathin transnasal endoscopy. Their average age was 65.2 ± 11.4 years. The male-female ratio was 2.5:1. All cases were examined using conventional white-light imaging (WLI) and nonmagnified NBI. When a depressed lesion was detected in the stomach, it was examined using WLI, then NBI close examination (at about 3 mm). We observed the mucosal structure of the lesion using close visualization with NBI. Concerning mucosal structural changes, we looked for a clear demarcation line between the lesion and the surrounding mucosa, and loss, irregularity, or nonuniformity of the lesion mucosal microsurface pattern.

RESULTS

A total of 52 depressed lesions were examined. The histological diagnosis was cancer for 8 lesions, and noncancer for 44 lesions. WLI examination yielded a sensitivity of 50.0% (4/8), specificity of 63.6% (28/44), and accuracy 61.5% (32/52). On the other hand, NBI close examination yielded a sensitivity of 87.5% (7/8), specificity of 93.2% (41/44), and accuracy of 92.3% (48/52), significantly higher.

CONCLUSION

NBI close examination using ultrathin transnasal endoscopy enables mucosal diagnosis even without magnification and was considered to be an effective technique for improving endoscopic diagnosis.

Evaluation of preferable insertion routes for esophagogastroduodenoscopy using ultrathin endoscopes

AIM: To evaluate the discomfort associated with esophagogastroduodenoscopy (EGD) using an ultrathin endoscope through different insertion routes.

METHODS: This study (January 2012-March 2013) included 1971 consecutive patients [male/female (M/F), 1158/813, 57.5 ± 11.9 years] who visited a single institute for annual health checkups. Transnasal EGD was performed in 1394 patients and transoral EGD in 577. EGD-associated discomfort was assessed using a visual analog scale score (VAS score: 0-10).

RESULTS: Multivariate analysis revealed gender (M vs F: 4.02 ± 2.15 vs 5.06 ± 2.43) as the only independent predictor of the VAS score in 180 patients who underwent EGD for the first time; whereas it revealed gender (M vs F 3.60 ± 2.20 vs 4.84 ± 2.37), operator, age group (A: < 39 years; B: 40-49 years; C: 50-59 years; D: 60-69 years; E: > 70 years; A/B/C/D/E: 4.99 ± 2.32/4.34 ± 2.49/4.19 ± 2.31/3.99 ± 2.27/3.63 ± 2.31), and type of insertion as independent predictors in the remaining patients. Subanalysis for gender, age group, and insertion route revealed that the VAS score decreased with age regardless of gender and insertion route, was high in female patients regardless of age and insertion route, and was low in males aged over 60 years who underwent transoral insertion.

CONCLUSION: Although comprehensive analysis revealed that the insertion route may not be an independent predictor of the VAS score, transoral insertion may reduce EGD-associated discomfort in elderly patients.

Usefulness of ultraslim endoscopy with flexible spectral imaging color enhancement for detection of gastric neoplasm: a preliminary study

PURPOSE

Transnasal endoscopy with ultraslim endoscope has rapidly spread in Japan. Ultraslim endoscopy provides less resolution than that of conventional endoscopy and may lead to missed screening of early gastric carcinoma. We evaluated the efficacy of ultraslim endoscopy with flexible spectral imaging color enhancement (FICE) for the diagnosis of early gastric carcinoma.

METHODS

This study included 20 consecutive patients in whom 22 gastric neoplasms were resected by endoscopic submucosal dissection (ESD) between April 2011 and January 2012 in Yamaguchi University Hospital. Prior to ESD, marking dots were made during observation with ultraslim endoscopy with FICE. We evaluated en bloc resection rate and tumor visibility with the FICE system.

RESULTS

All tumors were resected with sufficient lateral margin. Only one case had tumor cells in the vertical margin. En bloc resection rate was 95.5 % (21/22 lesions). Ultraslim endoscopy with FICE more clearly visualized tumor margin than did conventional endoscopy. Especially, the effect was remarkable in discolored lesions (100.0 %, 3/3 lesions).

CONCLUSIONS

Ultraslim endoscopy with FICE improved visibility of gastric neoplasms.

Training in endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) represents an important advancement in the therapy of early neoplastic gastrointestinal lesions by providing higher en-bloc curative resection rate with lower recurrence compared to endoscopic mucosal resection (EMR) and by sparing the involved organ and protecting patient’s quality of life. Despite these advantages ESD is associated with long procedure times and a higher rate of complications, making ESD a challenging procedure which requires advanced endoscopic skills. Thus, there has been a recognized need for structured training system for ESD to enhance trainee experience and, to reduce the risks of complications and inadequate treatment. ESD has a very flat learning curve. However, we do not have uniformly accepted benchmarks for competency. Nevertheless, it appears that, in Japan, more than 30 supervised gastric ESD procedures are required to achieve technical proficiency and minimize complications. A number of training algorithms have been proposed in Japan with the aim to standardize ESD training. These algorithms cannot be directly applied in the West due to substantial differences including the availability of highly qualified mentors, the type of pathology seen, choice of devices, and trainee’s background. We propose a training algorithm for Western physicians which integrates both hands-on training courses, animal model work as well as visits to expert centers. No specific preceptor training programs have been yet developed but there is a consensus that these programs are important for permeation of ESD worldwide.

Training in endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) represents an important advancement in the therapy of early neoplastic gastrointestinal lesions by providing higher en-bloc curative resection rate with lower recurrence compared to endoscopic mucosal resection (EMR) and by sparing the involved organ and protecting patient's quality of life. Despite these advantages ESD is associated with long procedure times and a higher rate of complications, making ESD a challenging procedure which requires advanced endoscopic skills. Thus, there has been a recognized need for structured training system for ESD to enhance trainee experience and, to reduce the risks of complications and inadequate treatment. ESD has a very flat learning curve. However, we do not have uniformly accepted benchmarks for competency. Nevertheless, it appears that, in Japan, more than 30 supervised gastric ESD procedures are required to achieve technical proficiency and minimize complications. A number of training algorithms have been proposed in Japan with the aim to standardize ESD training. These algorithms cannot be directly applied in the West due to substantial differences including the availability of highly qualified mentors, the type of pathology seen, choice of devices, and trainee's background. We propose a training algorithm for Western physicians which integrates both hands-on training courses, animal model work as well as visits to expert centers. No specific preceptor training programs have been yet developed but there is a consensus that these programs are important for permeation of ESD worldwide.

The current state of diagnosis and treatment for early gastric cancer

The prognosis for gastric cancer depends on its stage; so, detection in the early stage of disease is important, when complete and curative removal is possible. Accurate diagnosis can be facilitated by a sound understanding of the basic findings of white light endoscopy of early gastric cancer, and diagnosis can be refined further by the combined use of other imaging modalities such as image-enhanced endoscopy including chromoendoscopy and endoscopic ultrasonography. Minimally invasive endoscopic treatment has come to be the preferred therapeutic approach for early gastric cancer. In addition to conventional endoscopic mucosal resection, a new technique known as endoscopic submucosal dissection (ESD) has spread rapidly worldwide. Indeed, strategies for ESD have been established, devices developed, its indications expanded, and its safety and long-term results extensively reported. Some unique combination therapies involving endoscopy and surgical treatment have also been reported. It is anticipated that the number of patients undergoing endoscopic therapy will continue to increase, and the ongoing developments in endoscopic treatment are expected not only to improve gastric cancer prognosis but also to maintain good quality of life after treatment.

Flexible imaging color enhancement improves visibility of transnasal endoscopic images in diagnosing esophageal varices: a multicenter prospective blinded study

OBJECTIVE

To clarify the usefulness of transnasal esophagogastroduodenoscope (N-EGD) with all flexible imaging color enhancement (FICE) patterns (0-9) for the diagnosis of esophageal varices (EV).

METHODS

A total of 50 patients with EV were examined during the same period by N-EGD without sedation and by peroral endoscopy (O-EGD) with sedation. The visibility of treatment scars, microvessels, recurrent EV and red color sign (RCS) were measured. Visibility was evaluated by five blinded observers (poor-good: 0-10), and the effect of both endoscopic examinations on the cardiorespiratory function of the patients was measured.

RESULTS

The image scores for O-EGD and N-EGD with ordinary mode and N-EGD with FICE were 7.3 ± 1.2, 6.1 ± 1.0 and 6.9 ± 1.0 for treatment scars; 7.2 ± 1.4, 6.2 ± 1.2 and 7.3 ± 1.0 for microvessels; 7.2 ± 1.2, 6.1 ± 1.0 and 7.1 ± 1.0 for recurrent EV and 7.2 ± 1.3, 6.1 ± 1.3, and 7.2 ± 1.2 for RCS, respectively (intraclass correlation coefficients > 0.6). When FICE patterns 2, 6 and 9 were used, visibility was much improved. Ten minutes after insertion, the double product values in the N-EGD with the FICE group were significantly better (P < 0.05).

CONCLUSIONS

N-EGD with FICE is very useful for the diagnosis of EV and can improve the visibility of N-EGD on each lesion to the same level as that of O-EGD. N-EGD with FICE does not require sedation and may reduce the risk of hepatic encephalopathy.

Narrow-band imaging on screening of esophageal lesions using an ultrathin transnasal endoscopy

BACKGROUND AND AIM

Ultrathin transnasal endoscopy, used extensively in Japan, is considered to have inferior image quality and suction performance, and questionable diagnostic performance. So the aim of the present study was to compare the diagnostic performance of white light (WL) examination and non-magnified narrow-band imaging (NBI) examination in screening for esophageal disorders with ultrathin transnasal endoscopy.

METHODS

A prospective case study of 105 consecutive patients screened for upper gastrointestinal disorders at a single clinic in Tokyo Medical University Hospital. All subjects were diagnosed using WL, NBI and Lugol-staining examinations. Areas ≥ 5 mm clearly not a Lugol-staining lesion were defined as esophageal disorders and the rates of detection of the two examination methods (WL vs NBI) were compared.

RESULTS

For WL examination, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy (concordance rate) for esophageal disorders were 19.6%, 98.1%, 90.9%, 55.4%, and 59.2%, respectively, versus 60.8% 96.2%, 93.9%, 71.4%, and 78.6% for NBI.

CONCLUSION

A useful level of diagnostic performance for esophageal disorders can be achieved with non-magnified narrow-band NBI ultrathin transnasal endoscopy.

Unsedated transnasal ultrathin esophagogastroduodenoscopy may provide better diagnostic performance in gastroesophageal reflux disease

Transnasal ultrathin esophagogastroduodenoscopy (N-EGD) with less gagging reflexes under non-sedation is likely suitable for the diagnosis of gastroesophageal reflux disease (GERD), however, N-EGD might have drawbacks, including its low image resolution. Limited information is available regarding the diagnosability of N-EGD for GERD. We compared the utility and gagging reflexes of three different endoscopies, including N-EGD, ultrathin transoral EGD (UTO-EGD) and conventional oral EGD (CO-EGD), in the diagnosis of GERD. We performed screening endoscopy in 1580 patients (N-EGD n=727, UTO-EGD n=599, CO-EGD n=254) and compared the frequency distributions of the severity of reflux esophagitis, hiatus hernia, and Barrett's epithelium to estimate the diagnostic performance of each endoscopy. We also analyzed patients' tolerability of endoscopy by the subjective evaluation of gagging reflexes. In the diagnosis of reflux esophagitis and Barrett's epithelium, there was no significant difference in the frequency distributions of the severity of the diseases among three EGDs. However, the incidence of Barrett's epithelium was higher than that in the previous nationwide survey of GERD in Japan. The evaluated size of hiatus hernia was smaller in N-EGD than in two other peroral endoscopies. The size of hiatus hernia correlated significantly with severity of gagging reflexes that was also lowest when diagnosed with N-EGD. N-EGD had an equivalent performance in the diagnosis of reflux esophagitis and Barrett's epithelium compared with CO-EGD. Enlargement of hiatus hernia induced by gagging reflexes was minimal in N-EGD, resulting in its better performance in the diagnosis of Barrett's epithelium.

High-definition endoscopy and magnifying endoscopy combined with narrow band imaging in gastric cancer

Gastric cancer is the third common cancer and is the second leading cause of cancer deaths worldwide. Endoscopy is being increasingly used for gastric cancer screening because of a high detection rate. Despite promising data, the technique depends heavily on the availability of endoscopic instruments and expertise for mass screening. Furthermore, the introduction of various new endoscopic devices and techniques may enhance the value of endoscopy in efficacious cancer screening. High-definition endoscopy and image-enhanced endoscopy, including narrow band imaging, are the key modalities in advanced endoscopic imaging in gastric cancer.