Linked color imaging improves endoscopic diagnosis of active Helicobacter pylori infection

Artificial Intelligence for the Prediction of Helicobacter Pylori Infection in Endoscopic Images: Systematic Review and Meta-Analysis Of Diagnostic Test Accuracy

BACKGROUND

Helicobacter pylori plays a central role in the development of gastric cancer, and prediction of H pylori infection by visual inspection of the gastric mucosa is an important function of endoscopy. However, there are currently no established methods of optical diagnosis of H pylori infection using endoscopic images. Definitive diagnosis requires endoscopic biopsy. Artificial intelligence (AI) has been increasingly adopted in clinical practice, especially for image recognition and classification.

OBJECTIVE

This study aimed to evaluate the diagnostic test accuracy of AI for the prediction of H pylori infection using endoscopic images.

METHODS

Two independent evaluators searched core databases. The inclusion criteria included studies with endoscopic images of H pylori infection and with application of AI for the prediction of H pylori infection presenting diagnostic performance. Systematic review and diagnostic test accuracy meta-analysis were performed.

RESULTS

Ultimately, 8 studies were identified. Pooled sensitivity, specificity, diagnostic odds ratio, and area under the curve of AI for the prediction of H pylori infection were 0.87 (95% CI 0.72-0.94), 0.86 (95% CI 0.77-0.92), 40 (95% CI 15-112), and 0.92 (95% CI 0.90-0.94), respectively, in the 1719 patients (385 patients with H pylori infection vs 1334 controls). Meta-regression showed methodological quality and included the number of patients in each study for the purpose of heterogeneity. There was no evidence of publication bias. The accuracy of the AI algorithm reached 82% for discrimination between noninfected images and posteradication images.

CONCLUSIONS

An AI algorithm is a reliable tool for endoscopic diagnosis of H pylori infection. The limitations of lacking external validation performance and being conducted only in Asia should be overcome.

TRIAL REGISTRATION

PROSPERO CRD42020175957; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=175957.

The role of linked color imaging in endoscopic diagnosis of Helicobacter pylori associated gastritis

OBJECTIVE

Linked color imaging (LCI), a novel image-enhanced endoscopy, can make it easy to recognize differences in mucosal color. It may be helpful for diagnosing H. pylori associated gastritis and H. pylori infection status. We investigated whether LCI could improve the diagnostic accuracy of H. pylori associated gastritis.

MATERIALS AND METHODS

Upper endoscopy was performed for 100 patients using white light imaging (WLI) and LCI. During the exam, endoscopic video was recorded. It was then analyzed by four expert endoscopists. They reviewed these videos for endoscopic diagnosis of atrophic gastritis, metaplastic gastritis, nodular gastritis and H. pylori infection. Tissue biopsies with rapid urease test were done to confirm H. pylori infection status and intestinal metaplasia.

RESULTS

Kappa values for the inter-observer variability among the four endoscopists were fair to moderate under WLI and fair to good under LCI. Sensitivity, specificity, positive predictive value and negative predictive value for diagnosing H. pylori infection using WLI were 32.4%, 93.3%, 85.2% and 53.6%, respectively, while those for LCI were 57.4%, 91.3%, 88.7% and 64.3%, respectively. Total diagnostic accuracies for diagnosing H. pylori infection using WLI/LCI were 70.8%/78.8%. The accuracy and sensitivity of LCI for diagnosing H. pylori infection were significantly higher than those of WLI (p < .001 for both). However, there were no significant differences in the accuracy, sensitivity or specificity for diagnosing metaplastic gastritis between LCI and WLI.

CONCLUSIONS

LCI has better diagnostic accuracy for H. pylori infection status than WLI. Clinical trial registration number: KCT0003674.

Comparison Between Linked Color Imaging and Blue Laser Imaging for Improving the Visibility of Flat Colorectal Polyps: A Multicenter Pilot Study

INTRODUCTION

Linked color imaging (LCI) and blue laser imaging-bright (BLI-b) improve the visibility of gastrointestinal lesions. In this multicenter study, we compared the effects of LCI and BLI-b on the visibility of flat polyps with visibility scores and color difference (CD) values, including fast-withdrawal and large-monitor observation.

METHODS

We recorded 120 videos of 40 consecutive flat polyps (2-20 mm), adenoma, and sessile serrated adenoma and polyp (SSA/P), using white light imaging (WLI), BLI-b, and LCI from July 2017 to December 2017. All videos were evaluated by eight endoscopists according to a published polyp visibility score of 4 (excellent) to 1 (poor). Additionally, 1.5 ×faster and 1.7 ×sized videos were evaluated. Moreover, we calculated the CD values for each polyp in three modes.

RESULTS

The mean LCI scores (3.1 ± 0.9) were significantly higher than the WLI scores (2.5 ± 1.0, p < 0.001) but not significantly higher than the BLI-b scores (3.0 ± 1.0). The scores of faster videos on LCI (3.0 ± 1.1) were significantly higher than WLI (2.0 ± 1.0, p < 0.001) and BLI-b (2.8 ± 1.1, p = 0.03). The scores of larger-sized videos on LCI were not significantly higher than those of WLI or BLI-b. The CD value of LCI (18.0 ± 7.7) was higher than that of WLI (11.7 ± 7.0, p < 0.001), but was not significantly higher than that of BLI-b (16.6 ± 9.6). The CD value of LCI was significantly higher than that of BLI-b for adenoma, but the CD value of BLI-b was significantly higher than that of LCI for SSA/P.

CONCLUSIONS

The superiority of LCI to BLI-b was proven for the visibility of adenoma and fast observation.

Guidelines for endoscopic diagnosis of early gastric cancer

The Japan Gastroenterological Endoscopy Society developed the Guideline for Endoscopic Diagnosis of Early Gastric Cancer based on scientific methods. Endoscopy for the diagnosis of early gastric cancer has been acknowledged as a useful and highly precise examination, and its use has become increasingly more common in recent years. However, the level of evidence in this field is low, and it is often necessary to determine recommendations based on expert consensus only. This clinical practice guideline consists of the following sections to provide the current guideline: [I] Risk stratification of gastric cancer before endoscopic examination, [II] Detection of early gastric cancer, [III] Qualitative diagnosis of early gastric cancer, [IV] Diagnosis to choose the therapeutic strategy for gastric cancer, [V] Risk stratification after endoscopic examination, and [VI] Surveillance of early gastric cancer.

Optimized diagnosis of Helicobacter pylori and tailored eradication therapy for preventing gastric cancer: a proposal for SHAKE strategy

INTRODUCTION

To decrease gastric cancer-related mortality, the Korean National Cancer Screening Program provides biennial screening gastroscopy to all individuals aged >40 years. However, a test-and-treat strategy of Helicobacter pylori for preventing gastric cancer has not been established.

AREAS COVERED

In this review, we present up-to-date results of endoscopic findings of H. pylori gastritis, optimal sites for H. pylori detection, gastric cancer risk assessment using serum pepsinogen, tailored eradication based on the antimicrobial resistance against H. pylori, and post-eradication surveillance.

EXPERT OPINION

Here we propose approaches to H. pylori diagnosis and treatment for preventing gastric cancer, termed 'Screening for H. pylori in Korea and Eradication (SHAKE)' strategy. This strategy consists of the following: (1) optimized H. pylori diagnosis, (2) individualized management based on the H. pylori infection status, and (3) tailored eradication therapy. H. pylori gastritis can be diagnosed by endoscopic observation of the gastric mucosal pattern at the greater curvature of the corpus. Measurement of the serum pepsinogen I/II ratio is useful for assessing the risk of gastric cancer. As a first-line treatment, tailored eradication based on the results of molecular testing is effective in a country with a high rate of clarithromycin-resistant H. pylori.

Benefits of linked color imaging for recognition of early differentiated-type gastric cancer: in comparison with indigo carmine contrast method and blue laser imaging

BACKGROUND AND AIM

Linked color imaging (LCI) is a novel endoscopy system, which enhances slight differences in mucosal color. However, whether LCI is more useful than other kinds of image-enhanced endoscopy (IEE) in recognizing early gastric cancer remains unclear. This study aimed to evaluate LCI efficacy compared with the indigo carmine contrast method (IC), and blue laser imaging-bright (BLI-brt) in early differentiated-type gastric cancer recognition.

METHODS

We retrospectively analyzed early differentiated-type gastric cancer, which were examined by all four imaging techniques (white light imaging, IC, LCI, BLI-brt) at Asahi University Hospital from June 2014 to November 2018. Both subjective evaluation (using ranking score: RS) and objective evaluation (using color difference score: CDS) were adopted to quantify early differentiated-type gastric cancer recognition.

RESULTS

During this period, 87 lesions were enrolled in this study. Both RS and CDS of LCI were significantly higher (p < 0.01) than those of IC and BLI-brt. Both RS and CDS of BLI-brt had no significant difference compared with those of IC. Subgroup analysis revealed that LCI was especially useful in post-Helicobacter pylori eradication patients and flat or depressed lesions compared with IC and BLI-brt.

CONCLUSIONS

LCI appears to be more beneficial for the recognition of early differentiated-type gastric cancer in endoscopic screenings than IC and BLI-brt from the middle to distant view.

Quality indicators in diagnostic upper gastrointestinal endoscopy

Upper gastrointestinal (UGI) endoscopy contributes a major clinical service with consistently growing demand around the world. Its utility corresponds to varying epidemiological issues throughout the globe, with cancer screening and surveillance being of the utmost priority. Despite high accuracy in neoplasia detection, UGI endoscopy remains a highly operator-dependent procedure, characterized by a substantial rate of missed pathology. Despite an overall lack of high-quality performance measures, there is an increased level of awareness about the need for quality control of this procedure, which is reflected in several guidelines and position statements published in recent years. It is widely recognized that quality assessment should go beyond mere technical aspects of the examination, and include both pre- and post-procedural factors. By this means, quality control encompasses the entire patient experience with the health care provider, from appropriate indication and physical assessment, through high-quality endoscopy service, to appropriate follow up and patient satisfaction. This article aims to review the available and emerging quality metrics for UGI endoscopy, taken mostly from Western endoscopy societies, with references to Asian recommendations where appropriate. The paper is limited solely to diagnostic UGI endoscopy and does not include performance measures for therapeutic procedures.

RGB Pixel Brightness Characteristics of Linked Color Imaging in Early Gastric Cancer: A Pilot Study

Background and Aims

Linked color imaging (LCI) helps screen and diagnose for early gastric cancer by color contrast in different mucosa. RGB (red, green, and blue) pixel brightness quantifies colors, which is relatively objective. Limited studies have combined LCI images with RGB to help screen for early gastric cancer (EGC). We aimed to evaluate the RGB pixel brightness characteristics of EGC and noncancer areas in LCI images.

Methods

We retrospectively reviewed early gastric cancer (EGC) patients and LCI images. All pictures were evaluated by at least two endoscopic physicians. RGB pixel brightness analysis of LCI images was performed in MATLAB software to compare the cancer with noncancer areas. Receiver operating characteristic (ROC) curve was analyzed for sensitivity, specificity, cut-off, and area under the curve (AUC).

Results

Overall, 38 early gastric cancer patients were enrolled with 38 LCI images. Pixel brightness of red, green, and blue in cancer was remarkably higher than those in noncancer areas (190.24 ± 37.10 vs. 160.00 ± 40.35, p < 0.001; 117.96 ± 33.91 vs. 105.33 ± 30.01, p = 0.039; 114.36 ± 34.88 vs. 90.93 ± 30.14, p < 0.001, respectively). Helicobacter plyori (Hp) infection was not relevant to RGB distribution of EGC. Whether the score of Kyoto Classification of Gastritis (KCG) is ≥4 or <4, the pixel brightness of red, green, and blue was not disturbed in both cancer and noncancer (p > 0.05). Receiver operating characteristic (ROC) curve for differentiating cancer from noncancer was calculated. The maximum area under the curve (AUC) was 0.767 in B/G, with a sensitivity of 0.605, a specificity of 0.921, and a cut-off of 0.97.

Conclusions

RGB pixel brightness was useful and more objective in distinguishing early gastric cancer for LCI images.

Clinical significance and influencing factors of linked color imaging technique in real-time diagnosis of active Helicobacter pylori infection

Background:

Determining the Helicobacter pylori (H. pylori) infection state during the gastroscopic process is important but still challenging. The linked color imaging (LCI) technique might emphasize the mucosal color change after H. pylori infection, which might help the diagnosis. In the present study, we aimed to compare the LCI technique with traditional white light imaging (WLI) endoscopy for diagnosing active H. pylori infection.

Methods:

We collected and analyzed gastroscopic images from 103 patients in our hospital from November 2017 to March 2018, including both LCI and WLI modes. All images were randomly disordered and independently evaluated by four endoscopists who were blinded to the H. pylori status of patients. In addition, the H. pylori state was determined by both rapid urease test and pathology staining. The sensitivity, specificity, positive prediction value (PPV), and negative prediction value (NPV) were calculated for the detection of H. pylori infection. Moreover, the kappa value and interclass correlation coefficient (ICC) were used to evaluate the inter-observer variety by SPSS 24.0 software.

Results:

Of the 103 enrolled patients, 27 of them were positive for H. pylori infection, while the 76 patients were negative. In total, 388 endoscopic images were selected, including 197 WLI and 191 LCI. The accuracy rate for H. pylori evaluation in the corpus LCI group was significantly higher than other groups (81.2% vs. 64.3%–76.5%, χ² = 34.852, P < 0.001). Moreover, the corpus LCI group had the optimal diagnostic power with the sensitivity of 85.41% (95% confidence interval [CI]: 76.40%–91.51%), the specificity of 79.71% (95% CI: 74.38%–84.19%), the PPV of 59.42% (95% CI: 50.72%–67.59%), and the NPV of 94.02% (95% CI: 89.95%–96.56%), respectively. The kappa values between different endoscopists were higher with LCI than with WLI (0.433–0.554 vs. 0.331–0.554). Consistently, the ICC value was also higher with LCI than with WLI (0.501 [95% CI: 0.429–0.574] vs. 0.397 [95% CI: 0.323–0.474]). We further analyzed the factors that might lead to misjudgment, revealing that active inflammation might disturb WLI judgment (accuracy rate: 58.70% vs. 76.16%, χ² = 21.373, P < 0.001). Atrophy and intestinal metaplasia might affect the accuracy of the LCI results (accuracy rate: 66.96% vs. 73.47%, χ² = 2.027; 68.42% vs. 73.53%, χ² = 1.594, respectively); however, without statistical significance (P = 0.154 and 0.207, respectively).

Conclusions:

The application of LCI at the corpus to identify H. pylori infection is reliable and superior to WLI. The inter-observer variability is lower with LCI than with WLI.

Trial registration:

Chinese Clinical Trial Registry: ChiCTR1800016730; http://www.chictr.org.cn/showproj.aspx?proj=28400

Potential of automatic diagnosis system with linked color imaging for diagnosis of Helicobacter pylori infection

BACKGROUND AND AIM

It is necessary to establish universal methods for endoscopic diagnosis of Helicobacter pylori (HP) infection, such as computer-aided diagnosis. In the present study, we propose a multistage diagnosis algorithm for HP infection.

METHODS

The aims of this study are to: (i) to construct an interpretable automatic diagnostic system using a support vector machine for HP infection; and (ii) to compare the diagnosis capability of our artificial intelligence (AI) system with that of endoscopists. Presence of an HP infection determined through linked color imaging (LCI) was learned through machine learning. Trained classifiers automatically diagnosed HP-positive and -negative patients examined using LCI. We retrospectively analyzed the new images from 105 consecutive patients; 42 were HP positive, 46 were post-eradication, and 17 were uninfected. Five endoscopic images per case taken from different areas were read into the AI system, and used in the HP diagnosis.

RESULTS

Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the diagnosis of HP infection using the AI system were 87.6%, 90.4%, 85.7%, 80.9%, and 93.1%, respectively. Accuracy of the AI system was higher than that of an inexperienced doctor, but there was no significant difference between the diagnosis of experienced physicians and the AI system.

CONCLUSIONS

The AI system can diagnose an HP infection with significant accuracy. There remains room for improvement, particularly for the diagnosis of post-eradication patients. By learning more images and considering a diagnosis algorithm for post-eradication patients, our new AI system will provide diagnostic support, particularly to inexperienced physicians.

A systematic review of the role of non-magnified endoscopy for the assessment of H. pylori infection

Background and study aims  There is growing interest in the endoscopic recognition of Helicobacter pylori infection, and application to routine practice. We present a systematic review of the current literature regarding diagnosis of H. pylori during standard (non-magnified) endoscopy, including adjuncts such as image enhancement and computer-aided diagnosis. Method  The Medline and Cochrane databases were searched for studies investigating performance of non-magnified optical diagnosis for H. pylori , or those which characterized mucosal features associated with H. pylori infection. Studies were preferred with a validated reference test as the comparator, although they were included if at least one validated reference test was used. Results  Twenty suitable studies were identified and included for analysis. In total, 4,703 patients underwent investigation including white light endoscopy, narrow band imaging, i-scan, blue-laser imaging, and computer-aided diagnostic techniques. The endoscopic features of H. pylori infection observed using each modality are discussed and diagnostic accuracies reported. The regular arrangement of collecting venules (RAC) is an important predictor of the H. pylori -naïve stomach. "Mosaic" and "mottled" patterns have a positive association with H. pylori infection. The "cracked" pattern may be a predictor of an H. pylori- negative stomach following eradication. Conclusions  This review summarizes current progress made in endoscopic diagnosis of H. pylori infection. At present there is no single diagnostic approach that provides validated diagnostic accuracy. Further prospective studies are required, as is development of a validated classification system. Early studies in computer-aided diagnosis suggest potential for a high level of accuracy but real-time results are awaited.

Recent advances in diagnostic upper endoscopy

BACKGROUND

Esophageo-gastro-duodenoscopy (EGD) is an important procedure used for detection and diagnosis of esophago-gastric lesions. There exists no consensus on the technique of examination.

AIM

To identify recent advances in diagnostic EGDs to improve diagnostic yield.

METHODS

We queried the PubMed database for relevant articles published between January 2001 and August 2019 as well as hand searched references from recently published endoscopy guidelines. Keywords used included free text and MeSH terms addressing quality indicators and technological innovations in EGDs. Factors affecting diagnostic yield and EGD quality were identified and divided into the follow segments: Pre endoscopy preparation, sedation, examination schema, examination time, routine biopsy, image enhanced endoscopy and future developments.

RESULTS

We identified 120 relevant abstracts of which we utilized 67 of these studies in our review. Adequate pre-endoscopy preparation with simethicone and pronase increases gastric visibility. Proper sedation, especially with propofol, increases patient satisfaction after procedure and may improve detection of superficial gastrointestinal lesions. There is a movement towards mandatory picture documentation during EGD as well as dedicating sufficient time for examination improves diagnostic yield. The use of image enhanced endoscopy and magnifying endoscopy improves detection of squamous cell carcinoma and gastric neoplasm. The magnifying endoscopy simple diagnostic algorithm is useful for diagnosis of early gastric cancer.

CONCLUSION

There is a steady momentum in the past decade towards improving diagnostic yield, quality and reporting in EGDs. Other interesting innovations, such as Raman spectroscopy, endocytoscopy and artificial intelligence may have widespread endoscopic applications in the near future.

Pre-Cancerous Stomach Lesion Detections with Multispectral-Augmented Endoscopic Prototype

In this paper, we are interested in the in vivo detection of pre-cancerous stomach lesions. Pre-cancerous lesions are unfortunately rarely explored in research papers as most of them are focused on cancer detection or conducted ex-vivo. For this purpose, a novel prototype is introduced. It consists of a standard endoscope with multispectral cameras, an optical setup, a fiberscope, and an external light source. Reflectance spectra are acquired in vivo on 16 patients with a healthy stomach, chronic gastritis, or intestinal metaplasia. A specific pipeline has been designed for the classification of spectra between healthy mucosa and different pathologies. The pipeline includes a wavelength clustering algorithm, spectral features computation, and the training of a classifier in a “leave one patient out” manner. Good classification results, around 80%, have been obtained, and two attractive wavelength ranges were found in the red and near-infrared ranges: [745, 755 nm] and [780, 840 nm]. The new prototype and the associated results give good arguments in favor of future common use in operating rooms, during upper gastrointestinal exploration of the stomach for the detection of stomach diseases.

Can image-enhanced endoscopy improve the diagnosis of Kyoto classification of gastritis in the clinical setting?

Endoscopic diagnosis of Helicobacter pylori (H. pylori) infection, the most common cause of gastric cancer, is very important to clarify high-risk patients of gastric cancer for reducing morbidity and mortality of gastric cancer. Recently, the Kyoto classification of gastritis was developed based on the endoscopic characteristics of H. pylori infection-associated gastritis for clarifying H. pylori infection status and evaluating risk factors of gastric cancer. Recently, magnifying endoscopy with narrow-band imaging (NBI) has reported benefits of the accuracy and reproducibility of endoscopic diagnosis for H. pylori-related premalignant lesions. In addition to NBI, various types of image-enhanced endoscopies (IEEs) are available including autofluorescence imaging, blue laser imaging, and linked color imaging. This review focuses on understanding the clinical applications and the corresponding evidences shown to improve the diagnosis of gastritis based on Kyoto classification using currently available advanced technologies of IEEs.

Color information from linked color imaging is associated with invasion depth and vascular diameter in superficial esophageal squamous cell carcinoma

OBJECTIVES

Accurate diagnosis of invasion depth is important for reliable treatment of esophageal squamous cell carcinoma (ESCC), but it is limited to the muscularis mucosae to slight submucosal invasion (MM/SM1). The diagnostic accuracy of invasion depth is unsatisfactory and remains to be improved. We aimed to investigate the association between the color of the superficial ESCC and invasion depth using linked color imaging (LCI) under light-emitting diode (LED) light sources.

METHODS

Lesions diagnosed as superficial ESCC were observed using white light imaging and then by LCI. The color values were calculated using Commission Internationale de l'Eclariage - L*a*b* color space, and the color difference was calculated according to invasion depth. The vascular diameters and vascular angles of the intrapapillary capillary loops were pathologically analyzed. Their correlation with mucosal color was also investigated by LCI.

RESULTS

In all, 52 lesions from 48 patients were analyzed. On the basis of invasion depth, the color difference between the normal mucosa and the lesion was larger in the MM/SM1 or deeper group than in the epithelium and the lamina propria mucosa (EP/LPM) group using LCI (P = 0.025). The vascular diameter was positively correlated with the b* color value (correlation coefficient = 0.302, P = 0.033).

CONCLUSION

Observation using LCI under LED light sources may improve the endoscopic diagnosis of the invasion depth of superficial ESCC. Further research is needed to validate its usefulness. (UMIN000024615).

Imaging Inflammation and Infection in the Gastrointestinal Tract

A variety of seemingly non-specific symptoms manifest within the gastrointestinal (GI) tract, particularly in the colon, in response to inflammation, infection, or a combination thereof. Differentiation between symptom sources can often be achieved using various radiologic studies. Although it is not possible to provide a comprehensive survey of imaging gastrointestinal GI tract infections in a single article, the purpose of this review is to survey several topics on imaging of GI tract inflammation and infections. The review discusses such modalities as computed tomography, positron emission tomography, ultrasound, endoscopy, and magnetic resonance imaging while looking at up-an-coming technologies that could improve diagnoses and patient comfort. The discussion is accomplished through examining a combination of organ-based and organism-based approaches, with accompanying selected case examples. Specific focus is placed on the bacterial infections caused by Shigella spp., Escherichia coli, Clostridium difficile, Salmonella, and inflammatory conditions of diverticulitis and irritable bowel disease. These infectious and inflammatory diseases and their detection via molecular imaging will be compared including the appropriate differential diagnostic considerations.

Differential diagnosis of Helicobacter pylori-associated gastritis with the linked-color imaging score

BACKGROUND

Helicobacter pylori (H. pylori) infection in gastric mucosa is the main risk factor for gastric cancer. The purpose of this study was to assess the value of the linked-color imaging (LCI) score for the identification of H. pylori-associated gastritis.

METHODS

A total of 358 patients were enrolled in the study. H. pylori was positive in 127 cases and negative in 231 cases. Redness of fundus glands, granular erosion, purple mucus (+) and mucus lake turbidity were investigated by the LCI mode of endoscopy. Logistic regression was used to screen the observation indexes and their relative partial regression coefficients, which were helpful for the differential diagnosis of H. pylori infection. Then, each observation index was scored according to the partial regression coefficient.

RESULTS

Using a total scores of 3.5 as the cut-off value, the sensitivity and specificity were 83.8% and 99.5%, respectively, for the differential diagnosis of H. pylori gastritis. The area under the curve was 95.3%.

CONCLUSIONS

The LCI score showed high sensitivity and specificity for the differential diagnosis of H. pylori-associated gastritis and is an effective method for identifying H. pylori infection in gastric mucosa.

Linked color imaging identifies important risk factors associated with gastric cancer after successful eradication of Helicobacter pylori

BACKGROUND AND AIMS

Limited studies have evaluated the risk factors of gastric cancer (GC) after eradication of Helicobacter pylori (H pylori) using endoscopic findings. We aimed to investigate GC detection-related endoscopic findings after eradication of H pylori using linked color imaging (LCI), a novel image-enhanced endoscopy.

METHODS

This single-center, cross-sectional study evaluated background mucosa-associated endoscopic findings described in the Kyoto classification of gastritis in patients with newly detected GC after eradication of H pylori (CA group, n = 109) and those without GC (NC group, n = 85) using white-light imaging (WLI) and LCI.

RESULTS

Severe atrophy and map-like redness were significantly more frequent in the CA group than in the NC group using WLI (79.8% vs 63.5%, P = .01; 61.5% vs 37.7%, P = .001, respectively) and LCI (79.8% vs 63.5%, P = .01; 78.0% vs 45.9%, P < .0001, respectively). Regular arrangement of collecting venules (RAC) was significantly less frequent in the CA group than in the NC group using WLI (40.3% vs 64.7%, P = .0009) and LCI (37.6% vs 62.4%, P = .0006). Map-like redness was an independent positive risk factor (WLI: odds ratio [OR], 2.05; 95% confidence interval [CI], 1.09-3.87; P = .03; LCI: OR, 3.62; 95% CI, 1.88-6.97; P < .001), whereas RAC was an independent negative risk factor (WLI: OR, 0.42; 95% CI, 0.21-0.82; P = .01; LCI: OR, 0.46; 95% CI, 0.23-0.93, P = .03) for detection of GC after eradication of H pylori.

CONCLUSIONS

Map-like redness, which was identified more frequently using LCI than WLI, and the absence of RAC were associated with detection of GC after eradication of H pylori.

Linked color imaging for the detection of early gastrointestinal neoplasms

In routine upper and lower gastrointestinal endoscopy, overlooking neoplastic lesions is inevitable even for well-trained endoscopists. Various methods have been reported to improve the detection of gastrointestinal neoplasms including chromoendoscopy, special endoscopes, and processor and image enhanced technologies. Equipment-based image enhanced endoscopy (e-IEE) using narrow band imaging (NBI) and blue laser imaging (BLI) is useful to characterize known lesions with magnification at a close-up view. However, they are not useful for the early detection of superficial, pale neoplasms, or both because of the weak image at a distant view in a wide lumen such as the stomach or colon. Linked color imaging (LCI) is a novel pre- and post-processing technology developed by Fujifilm Corporation that has sufficient brightness to illuminate a wide lumen. LCI delineates early gastric cancers as orange-red and intestinal metaplasia as purple. LCI improves the adenoma detection rate in the colon and decreases the polyp miss rate. LCI contributes to the detection of superficial lesions throughout the gastrointestinal tract by enhancing the color contrast between the neoplasm and the surrounding mucosa. LCI can distinguish them by their specific color allocation based mainly on the distribution of capillaries. The authors believe that moving forward, LCI should be used in routine upper and lower gastrointestinal endoscopy.

Linked color imaging confers benefits in profiling H. pylori infection in the stomach

Background and study aims There is a high prevalence of Helicobacter pylori infection. White light endoscopy (WLE) can be used for evaluating the mucosal lesions, but it does not have high diagnostic efficiency. Linked color imaging (LCI) is a newly developed endoscopic imaging technique. The aim of this study was to compare LCI with WLE in detecting and staging H. pylori infection in the stomach in a randomized controlled clinical trial.

Patients and methods A total of 253 patients who had indications for gastroduodenoscopy were enrolled and randomized into Group A (n = 127), who underwent WLE followed by LCI, and Group B (n = 126), who underwent LCI followed by WLE. Clinical data were collected and the diagnostic accuracy of WLE and LCI was calculated and compared.

Results The overall diagnostic accuracy of WLE and LCI for H. pylori infection was 31.5 % (n = 40) and 50.4 % (n = 64) in Group A (P = 0.001), and 36.5 % (n = 46) and 49.2 % (n = 62) in Group B (P = 0.029). In both groups, LCI had higher sensitivity, specificity, and Youden index scores than WLE. Four stages were defined in the course of H. pylori infection in the stomach. LCI staging results were more highly consistent with pathological staging than were WLE staging results (kappa value 0.772 vs. 0.516). The LCI observations were closely correlated with the pathology.

Conclusion LCI had a higher diagnostic efficacy for H. pylori infection in the stomach. Endoscopic color features under LCI can help to stage and profile H. pylori-associated gastritis.

Predictability of gastric intestinal metaplasia by patchy lavender color seen on linked color imaging endoscopy

We aimed to investigate the ability of linked color imaging (LCI) versus white light endoscopy (WLE) to detect gastric intestinal metaplasia (GIM). One hundred and seven participants who underwent upper gastrointestinal endoscopy were included. Under WLE endoscopy, biopsies were performed on any suspected abnormal mucosal changes. Under LCI endoscopy, we tested whether the specific color feature of patchy lavender color (PLC) pathologically indicated GIM. Biopsies were randomly performed in participants who had neither PLC nor suspected lesions. The detection abilities of LCI and WLE were assessed by comparison of histological and endoscopic findings. A total of 41 participants had histological GIM. The total diagnostic accuracy rate for GIM by LCI was 79.44%, higher than that of WLE (40.19%) (P < 0.001). Moreover, LCI with targeted biopsies showed a significantly increased ability to detect GIM (P < 0.001). PLC observed in the gastric mucosa on LCI can guide endoscopic biopsies and increase the detection rate of GIM. Thus, LCI could be a good tool for detecting GIM. ClinicalTrials.gov Identifier: ChiCTR-DDD-17011326).

Relationship of Helicobacter pylori Infection with Gastric Black Spots Shown by Endoscopy

Objective The recently reported endoscopic finding of black spots is defined as black pigmentation in gastric mucosa. We attempted to clarify the relationship between the Helicobacter pylori infection status and black spot occurrence. Methods The study subjects were 1,600 individuals who underwent an annual medical checkup and whose H. pylori status could be determined. Upper endoscopic examinations were performed in all, and the presence of black spots in the stomach as well as the degree of gastric mucosal atrophy were determined. Results Among the 1,600 enrolled subjects, 784 underwent eradication for H. pylori, of whom 144 were originally H. pylori-positive and 672 H. pylori-negative. Black spots in the stomach were observed in 156 (9.8%). The rate of prevalence of black spots in the H. pylori-positive and H. pylori-negative subjects was 2.1% and 1.5%, respectively, while that in subjects after undergoing eradication of H. pylori was 18.2%. A multiple logistic regression analysis demonstrated that an older age and post-eradication status were significant factors for black spot occurrence, while proton pump inhibitor treatment showed a tendency to be a risk factor. In subjects with post-eradication status, a higher grade of gastric mucosal atrophy was a significant risk factor for the occurrence of black spots. Conclusion H. pylori post-eradication status and an older age were significant factors related to the appearance of black spots, and a higher grade of gastric mucosal atrophy was also a significant risk factor in subjects who had undergone successful eradication.

Utility of linked color imaging for endoscopic diagnosis of early gastric cancer

BACKGROUND

Linked color imaging (LCI) is a method of endoscopic imaging that emphasizes slight differences in red mucosal color.

AIM

To evaluate LCI in diagnostic endoscopy of early gastric cancer and to compare LCI and pathological findings.

METHODS

Endoscopic images were obtained for 39 patients (43 lesions) with early gastric cancer. Three endoscopists evaluated lesion recognition with white light imaging (WLI) and LCI. Color values in Commission Internationale de l'Eclairage (CIE) 1976 L*a*b* color space were used to calculate the color difference (ΔE) between cancer lesions and non-cancer areas. After endoscopic submucosal dissection, blood vessel density in the surface layer of the gastric epithelium was evaluated pathologically. The identical region of interest was selected for analyses of endoscopic images (WLI and LCI) and pathological analyses.

RESULTS

LCI was superior for lesion recognition (P < 0.0001), and ΔE between cancer and non-cancer areas was significantly greater with LCI than WLI (29.4 vs 18.6, P < 0.0001). Blood vessel density was significantly higher in cancer lesions (5.96% vs 4.15%, P = 0.0004). An a* cut-off of ≥ 24 in CIE 1976 L*a*b* color space identified a cancer lesion using LCI with sensitivity of 76.7%, specificity of 93.0%, and accuracy of 84.9%.

CONCLUSION

LCI is more effective for recognition of early gastric cancer compared to WLI as a result of improved visualization of changes in redness. Surface blood vessel density was significantly higher in cancer lesions, and this result is consistent with LCI image analysis.

Blue laser imaging-bright improves the real-time detection rate of early gastric cancer: a randomized controlled study

BACKGROUND AND AIMS

Blue laser imaging-bright (BLI-bright) has shown promise as a more useful tool for detection of early gastric cancer (EGC) than white-light imaging (WLI). However, the diagnostic performance of BLI-bright in the detection of EGC has not been investigated. We aimed to compare real-time detection rates of WLI with that of BLI-bright for EGC.

METHODS

This was a prospective, randomized, controlled study in 2 Japanese academic centers. We investigated 629 patients undergoing follow-up endoscopy for atrophic gastritis with intestinal metaplasia or surveillance after endoscopic resection of EGC. Patients were randomly assigned to receive primary WLI followed by BLI-bright or primary BLI-bright followed by WLI. The real-time detection rates of EGC were compared between primary WLI and primary BLI-bright.

RESULTS

There were 298 patients in each group. The real-time detection rate of EGC with primary BLI-bright was significantly greater than that with primary WLI (93.1% vs 50.0%; P = .001). Primary BLI-bright had a significantly greater ability to detect EGCs in patients with a history of endoscopic resection for EGC, no Helicobacter pylori infection in the stomach after eradication therapy, lesions with an open-type atrophic border, lesions in the lower third of the stomach, depressed-type lesions, small lesions measuring <10 mm and 10 to 20 mm in diameter, reddish lesions, well-differentiated adenocarcinomas, and lesions with a depth of invasion of T1a.

CONCLUSIONS

BLI-bright has a higher real-time detection rate for EGC than WLI. BLI-bright should be performed during surveillance endoscopy in patients at high risk for EGC. (Clinical trial registration number: UMIN000011324.).

[Diagnosis of Helicobacter pylori Infection]

Accurate diagnosis of Helicobacter pylori (H. pylori) infection is mandatory for the effective management of many gastroduodenal diseases. Currently, various diagnostic methods are available for detecting these infections, and the choice of method should take into account the clinical condition, accessibility, advantage, disadvantage, as well as cost-effectiveness. The diagnostic methods are divided into invasive (endoscopic-based) and non-invasive methods. Non-invasive methods included urea breath test, stool antigen test, serology, and molecular methods. Invasive methods included endoscopic imaging, rapid urease test, histology, culture, and molecular methods. In this article, we provide a review of the currently available options and recent advances of various diagnostic methods.

Diffuse redness in linked color imaging is useful for diagnosing current Helicobacter pylori infection in the stomach

Esophagogastroduodenoscopic examination shows diffuse redness of the mucosa of the gastric body, which can be identified as a deep reddish color. The present case underscores the importance of diffuse redness as a key endoscopic feature that enables prompt diagnosis of current Helicobacter pylori infection.

Improved Visibility of Barrett's Esophagus with Linked Color Imaging: Inter- and Intra-Rater Reliability and Quantitative Analysis

BACKGROUND/AIMS

To evaluate the usefulness of linked color imaging (LCI) and blue LASER imaging (BLI) in Barrett's esophagus (BE) compared with white light imaging (WLI).

METHODS

Five expert and trainee endoscopists compared WLI, LCI, and BLI images obtained from 63 patients with short-segment BE. Physicians assessed visibility as follows: 5 (improved), 4 (somewhat improved), 3 (equivalent), 2 (somewhat decreased), and one (decreased). Scores were evaluated to assess visibility. The inter- and intra-rater reliability (intra-class correlation coefficient) of image assessments were also evaluated. Images were objectively evaluated based on L* a* b* color values and color differences (ΔE*) in a CIELAB color space system.

RESULTS

Improved visibility compared with WLI was achieved for LCI: 44.4%, BLI: 0% for all endoscopists; LCI: 55.6%, BLI: 1.6% for trainees; and LCI: 47.6%, BLI: 0% for experts. The visibility score of trainees compared with experts was significantly higher for LCI (p = 0.02). Intra- and inter-rater reliability ratings for LCI compared with WLI were "moderate" for trainees, and "moderate-substantial" for experts. The ΔE* revealed statistically significant differences between WLI and LCI.

CONCLUSION

LCI improved the visibility of short-segment BE compared with WLI, especially for trainees, when evaluated both subjectively and objectively.

Blue Laser Imaging with a Small-Caliber Endoscope Facilitates Detection of Early Gastric Cancer

Conventional endoscopy often misses early gastric cancers with minimal red discoloration because they cannot be distinguished from inflamed mucosa. We treated a patient with a small early gastric cancer that was difficult to diagnose using conventional endoscopy. Conventional endoscopy using a small-caliber endoscope showed only subtle red discoloration of the gastric mucosa. However, blue laser imaging showed a clearly discolored area measuring 10 mm in diameter around the red lesion, which was distinct from the surrounding inflamed mucosa. Irregular vessels on the tumor surface (suspicious for early gastric cancer) were observed even with small-caliber endoscopy. Biopsy revealed a well-moderately differentiated tubular adenocarcinoma, and endoscopic submucosal dissection was performed. Histopathological examination of the specimen confirmed well-moderately differentiated adenocarcinoma localized to the mucosa with slight depression compared to the surrounding mucosa, consistent with the endoscopic findings. This small early gastric cancer became clearly visible with blue laser imaging using small-caliber endoscopy.

Artificial intelligence diagnosis of Helicobacter pylori infection using blue laser imaging-bright and linked color imaging: a single-center prospective study

Background

Deep learning is a type of artificial intelligence (AI) that imitates the neural network in the brain. We generated an AI to diagnose Helicobacter pylori (H. pylori) infection using blue laser imaging (BLI)-bright and linked color imaging (LCI). The aim of this pilot study was to establish an AI diagnosing system that predicts H. pylori infection status using endoscopic images to improve the accuracy and productivity of endoscopic examination.

Methods

A total of 222 enrolled subjects (105 H. pylori-positive) underwent esophagogastroduodenoscopy and a serum test for H. pylori IgG antibodies. During esophagogastroduodenoscopy, an endoscopist sequentially took 3 still images of the lesser curvature of the stomach using white light imaging (WLI), BLI-bright, and LCI. EG-L580NW endoscopic equipment (FUJIFILM Co., Japan) was used for the study. The specifications of the AI were as follows: operating system, Linux; neural network, GoogLeNet; framework, Caffe; graphic processor unit, Geforce GTX TITAN X (NVIDIA Co., USA).

Results

The area under the curve (AUC) on receiver operating characteristics analysis was 0.66 for WLI. In contrast, the AUCs of BLI-bright and LCI were 0.96 and 0.95, respectively. The AUCs obtained for BLI-bright and LCI were significantly larger than those for WLI (P<0.01).

Conclusions

The results demonstrate that the developed AI has an excellent ability to diagnose H. pylori infection using BLI-bright and LCI. AI technology with image-enhanced endoscopy is likely to become a useful image diagnostic tool.

Linked color imaging enhances endoscopic detection of sessile serrated adenoma/polyps

BACKGROUND AND STUDY AIMS

 Although new image-enhanced endoscopy (IEE) technologies such as blue laser imaging (BLI), BLI-bright, and linked color imaging (LCI) have been developed, their utility for the detection of sessile serrated adenoma/polyps (SSA/Ps) is still unclear. This study aimed to evaluate the utility of BLI, BLI-bright, and LCI for SSA/P detection in still image examinations and in a prospective randomized controlled trial (RCT).

PATIENTS AND METHODS

 A group of 6 expert and non-expert endoscopists read 200 endoscopic still images containing SSA/P lesions using white light image (WLI), BLI, BLI-bright, and LCI. Color differences were calculated using the color space method. A prospective RCT of tandem colonoscopy with WLI and LCI was performed. Patients with SSA/P and those with a history of SSA/P that had been endoscopically removed were enrolled and randomly allocated to WLI-LCI or LCI-WLI groups. Additional endoscopic detection rates for SSA/P were compared between the 2 groups.

RESULTS

 LCI showed the highest SSA/P detection rate among the 4 modes for both expert and non-expert endoscopists. The detection rate with LCI for the 6 expert endoscopists (mean 98.3 ± standard deviation 2.0 %) was significantly higher than that with WLI (86.7 ± 6.0 %, P  < 0.01). Likewise, the detection rate with LCI for the 6 non-expert endoscopists (92.3 ± 2.9 %) was significantly higher than that with WLI (72.7 ± 11.5 %, P  < 0.01). The color difference of SSA/P with LCI was the highest among the 4 modes, and was significantly higher than with WLI (median 15.9, (interquartile range 13.7 - 20.6) vs. 10.2, (7.6 - 14.2); P  < 0.0001). In the RCT, a total of 44 patients (WLI-LCI 22 vs. LCI-WLI 22) underwent colonoscopy. The additional detection rate for SSA/P in the second inspection in the WLI-LCI group (21.6 %, 8/37) was significantly higher than in the LCI-WLI group (3.2 %, 1/31; P  = 0.02). The small, flat, non-mucus and isochromatic SSA/Ps in the transverse colon were detected more frequently in the second inspection with LCI.

CONCLUSIONS

 LCI was the most sensitive mode for SSA/P detection among WLI, BLI, BLI-bright, and LCI in the still image examinations. Our RCT strongly suggests that LCI is superior to conventional WLI for SSA/P detection during colonoscopy. UMIN000017599.

Evaluation of the visibility of early gastric cancer using linked color imaging and blue laser imaging

Background

Blue laser imaging (BLI) and linked color imaging (LCI) are the color enhancement features of the LASEREO endoscopic system, which provide a narrow band light observation function and expansion and reduction of the color information, respectively.

Methods

We examined 82 patients with early gastric cancer (EGC) diagnosed between April 2014 and August 2015. Five expert and 5 non-expert endoscopists retrospectively compared images obtained on non-magnifying BLI bright mode (BLI-BRT) and LCI with those obtained via conventional white light imaging (WLI). Interobserver agreement was also assessed.

Results

In experts’ evaluation of the images, an improvement in visibility was observed in 73% (60/82) and 20% (16/82) of cases under LCI and BLI-BRT, respectively. In non-experts’ evaluation of the images, an improvement in visibility was observed in 76.8% (63/82) and 24.3% (20/82) of cases under LCI and BLI-BRT, respectively. There were no significant differences between experts and non-experts in the evaluation of the images. The improvement in visibility was significantly higher with LCI than with BLI-BRT in experts and non-experts (p < 0.01). With regard to tumor color on WLI, the improvement in the visibility of reddish and whitish tumors was significantly higher than that of isochromatic tumors when LCI was used. The improvement in visibility with LCI was observed in 71% (12/17) and 74% (48/65) of patients with and without Helicobacter pylori (Hp) eradication, respectively; no significant difference in improvement was observed between these groups. The interobserver agreement was good to satisfactory at ≥ 0.62.

Conclusions

In conclusion, our study showed that LCI improved the visibility of EGC, regardless of the level of endoscopists’ experience or Hp eradication in patients, particularly for EGCs with a reddish or whitish color. The improvement in visibility was significantly higher with LCI than that with BLI.

Objective Endoscopic Analysis with Linked Color Imaging regarding Gastric Mucosal Atrophy: A Pilot Study

Objectives

We aimed to determine whether linked color imaging (LCI), a new image-enhanced endoscopy that enhances subtle differences in mucosal colors, can distinguish the border of endoscopic mucosal atrophy.

Methods

This study included 30 patients with atrophic gastritis. In endoscopy, we continuously took images in the same composition with both LCI and white light imaging (WLI). In each image, the color values of atrophic and nonatrophic mucosae were quantified using the International Commission on Illumination 1976 (L^∗, a^∗, b^∗) color space. Color differences at the atrophic border, defined as Euclidean distances of color values between the atrophic and nonatrophic mucosae, were compared between WLI and LCI for the overall cohort and separately for patients with Helicobacter pylori infection status.

Results

We found that the color difference became significantly higher with LCI than with WLI in the overall samples of 90 points in 30 patients. LCI was 14.79 ± 6.68, and WLI was 11.06 ± 5.44 (P < 0.00001). LCI was also more effective in both of the Helicobacter pylori-infected group (P = 0.00003) and the Helicobacter pylori-eradicated group (P = 0.00002).

Conclusions

LCI allows clear endoscopic visualization of the atrophic border under various conditions of gastritis, regardless of Helicobacter pylori infection status.

Application of Convolutional Neural Networks in the Diagnosis of Helicobacter pylori Infection Based on Endoscopic Images

BACKGROUND AND AIMS

The role of artificial intelligence in the diagnosis of Helicobacter pylori gastritis based on endoscopic images has not been evaluated. We constructed a convolutional neural network (CNN), and evaluated its ability to diagnose H. pylori infection.

METHODS

A 22-layer, deep CNN was pre-trained and fine-tuned on a dataset of 32,208 images either positive or negative for H. pylori (first CNN). Another CNN was trained using images classified according to 8 anatomical locations (secondary CNN). A separate test data set (11,481 images from 397 patients) was evaluated by the CNN, and 23 endoscopists, independently.

RESULTS

The sensitivity, specificity, accuracy, and diagnostic time were 81.9%, 83.4%, 83.1%, and 198s, respectively, for the first CNN, and 88.9%, 87.4%, 87.7%, and 194s, respectively, for the secondary CNN. These values for the 23 endoscopists were 79.0%, 83.2%, 82.4%, and 230±65min (85.2%, 89.3%, 88.6%, and 253±92min by 6 board-certified endoscopists), respectively. The secondary CNN had a significantly higher accuracy than endoscopists (by 5.3%; 95% CI, 0.3-10.2).

CONCLUSION

H. pylori gastritis could be diagnosed based on endoscopic images using CNN with higher accuracy and in a considerably shorter time compared to manual diagnosis by endoscopists.

Linked color imaging (LCI), a novel image-enhanced endoscopy technology, emphasizes the color of early gastric cancer

BACKGROUND AND STUDY AIMS

 Linked color imaging (LCI) and blue laser imaging (BLI) are novel image-enhanced endoscopy technologies with strong, unique color enhancement. We investigated the efficacy of LCI and BLI-bright compared to conventional white light imaging (WLI) by measuring the color difference between early gastric cancer lesions and the surrounding mucosa.

PATIENTS AND METHODS

 Images of early gastric cancer scheduled for endoscopic submucosal dissection were captured by LCI, BLI-bright, and WLI under the same conditions. Color values of the lesion and surrounding mucosa were defined as the average of the color value in each region of interest. Color differences between the lesion and surrounding mucosa (ΔE) were examined in each mode. The color value was assessed using the CIE L*a*b* color space (CIE: Commission Internationale d'Eclairage).

RESULTS

 We collected images of 43 lesions from 42 patients. Average ΔE values with LCI, BLI-bright, and WLI were 11.02, 5.04, and 5.99, respectively. The ΔE was significantly higher with LCI than with WLI ( P  < 0.001). Limited to cases of small ΔE with WLI, the ΔE was approximately 3 times higher with LCI than with WLI (7.18 vs. 2.25). The ΔE with LCI was larger when the surrounding mucosa had severe intestinal metaplasia ( P  = 0.04). The average color value of a lesion and the surrounding mucosa differed. This value did not have a sufficient cut-off point between the lesion and surrounding mucosa to distinguish them, even with LCI.

CONCLUSION

 LCI had a larger ΔE than WLI. It may allow easy recognition and early detection of gastric cancer, even for inexperienced endoscopists.

Diagnosis of Helicobacter pylori infection

Important progress is being made in endoscopic methods which allow clinicians to predict the presence of Helicobacter pylori based on characteristics of gastric mucosa and to obtain targeted biopsies. There are also important developments in molecular methods with various techniques derived from standard PCR, applied both on gastric biopsies and stool specimens. Progress is being made in microfluidic systems to get a reliable diagnosis in a very short time. The interest of the ¹³ C urea breath test has been confirmed as well as stool antigen tests. Attempts are being made to find biological markers of premalignant conditions by serology, other than pepsinogens.

Linked color imaging improves the visibility of various featured colorectal polyps in an endoscopist's visibility and color difference value

PURPOSE

Linked color imaging (LCI) by laser endoscopy is a novel narrow band light observation. In this study, we analyzed the efficacy of LCI for improving the various featured colorectal polyp's visibility utilizing a subjective endoscopist's visibility scoring and objective color difference (CD) value.

METHODS

We retrospectively reviewed two pictures both with white light (WL) and LCI for 54 consecutive neoplastic polyps 2-20 mm in size. All pictures were evaluated by four endoscopists according to a published polyp visibility score from four (excellent visibility) to one (poor visibility). Additionally, we calculated CD value between each polyp and surrounding mucosa in LCI and WL using an original software.

RESULTS

The mean polyp visibility scores of LCI (3.11 ± 1.05) were significantly higher than those of WL (2.50 ± 1.09, P < 0.001). The ratio of an endoscopist's poor visibility (polyp visibility scores 1 and 2) was significantly lower in LCI (27.9%) than WL (55.6%, P < 0.001). With respect to the CD analysis, the CD value of LCI was significantly higher than that of WL (33.3 ± 13.9 vs. 20.7 ± 13.6, P < 0.001). In a subgroup analysis, the polyp visibility scores and CD values of LCI about 24 diminutive polyps (≤5 mm) were higher than those of WL (3.29 ± 0.99 vs. 2.12 ± 0.99, P < 0.001; 31.6 ± 12.8 vs. 14.7 ± 7.6, P < 0.001). Additionally, the polyp visibility scores and CD values of LCI for polyps with any location, size, histology, and morphology were significantly higher than those of WL.

CONCLUSIONS

LCI improved the various featured polyp's visibility compared to WL in both polyp visibility scores and CD value.

Assessment of Endoscopic Mucosal Healing of Ulcerative Colitis Using Linked Colour Imaging, a Novel Endoscopic Enhancement System

BACKGROUND AND AIMS

Mucosal healing and control of intestinal mucosal inflammation are important treatment goals for maintaining clinical remission in ulcerative colitis [UC] patients. Here, we investigated the efficacy of linked colour imaging [LCI], a novel endoscopic enhancement system, for diagnosing mucosal inflammation in UC patients.

METHODS

All examinations were carried out with a LASEREO endoscopic system [FUJIFILM Co., Tokyo, Japan]. Fifty-two patients with UC were enrolled, and 193 areas assessed by LCI were examined. LCI patterns were classified as; A, no redness; B, redness with visible vessels; and C, redness without visible vessels. Regions of interest [ROIs] were set at biopsy sites, and the red colour in the ROI was calculated from the Commission internationale de l'éclairage [CIE] color space and digitized [LCI-index]. Biopsy specimens were taken at each ROI and evaluated with Matts histopathological grade. Thirty months was defined as the time interval between endoscopic diagnosis and relapse of UC.

RESULTS

Interobserver agreement for LCI classification was excellent between an expert and non-experts. Among areas with a Mayo endoscopic subscore of 0, 41.8% and 4.6% were classified as LCI-B and LCI-C, respectively. Among areas with a Mayo endoscopic subscore of 1, 60.5% and 34.6% were classified as LCI-C and LCI-B, respectively. The LCI index strongly correlated with the histopathological Matts score. Non-relapse rates significantly correlated with LCI classification [p = 0.0055], but not with Mayo endoscopic subscore [p = 0.0632].

CONCLUSION

Endoscopic LCI classification and LCI index can subdivide samples with the same Mayo endoscopic subscore. LCI may be a novel approach for evaluating colonic mucosal inflammation and for predicting outcome in UC patients.

Linked colour imaging benefits the endoscopic diagnosis of distal gastric diseases

Gastric diseases are common in China, and gastroduodenoscopy could provide accurate diagnoses. Our previous study verified that linked colour imaging (LCI) can improve endoscopic diagnostic accuracy. This study aimed for the first time to establish an LCI-based endoscopic model called colour-microstructure-vessel (CMV) criteria and validated its clinical feasibility for detecting distal gastric diseases manifested as red mucosal lesions under endoscopy in a cohort of 62 patients. Colour features were extracted from the endoscopic images and categorized into 3 types. Colour type 1 was a typical red; Colour type 2 was red ringed with purple and Colour type 3 was red with yellow in the centre and purple around the periphery, allowing for predicting chronic nonatrophic gastritis, chronic atrophic gastritis and gastric cancer. The sensitivity, specificity and Youden index of Colour type 3 with abnormal M or V for gastric cancer were 100.0%, 98.2% and 98.2%. The kappa values for intra-observer and inter-observer agreement for predicting the pathology were 0.834 and 0.791 for experienced endoscopists and 0.788 and 0.732 for endoscopy learners, and these values were comparable regardless of the experience of the endoscopists (P > 0.05). These findings support that the CMV criteria are a promising model for accurate endoscopic diagnosis.

Linked color imaging improves the visibility of colorectal polyps: a video study

BACKGROUND/STUDY AIM

 Linked color imaging (LCI) by a laser endoscope (Fujifilm Co, Tokyo, Japan) is a novel narrow band light observation. In this study, we aimed to investigate whether LCI could improve the visibility of colorectal polyps using endoscopic videos.

PATIENTS AND METHODS

 We prospectively recorded videos of consecutive polyps 2 - 20 mm in size diagnosed as neoplastic polyps. Three videos, white light (WL), blue laser imaging (BLI)-bright, and LCI, were recorded for each polyp by one expert. After excluding inappropriate videos, all videos were evaluated in random order by two experts and two non-experts according to a published polyp visibility score from four (excellent visibility) to one (poor visibility). Additionally, the relationship between polyp visibility scores in LCI and various clinical characteristics including location, size, histology, morphology, and preparation were analyzed compared to WL and BLI-bright.

RESULTS

 We analyzed 101 colorectal polyps (94 neoplastic) in 66 patients (303 videos). The mean polyp size was 9.0 ± 8.1 mm and 54 polyps were non-polypoid. The mean polyp visibility scores for LCI (2.86 ± 1.08) were significantly higher than for WL and BLI-bright (2.53 ± 1.15, P  < 0.001; 2.73 ± 1.47, P  < 0.041). The ratio of poor visibility (score 1 and 2) was significantly lower in LCI for experts and non-experts (35.6 %, 33.6 %) compared with WL (49.6 %, P  = 0.015, 50.5 %, P  = 0.046). The polyp visibility scores for LCI were significantly higher than those for WL for all of the factors. With respect to the comparison between BLI-bright and WL, the polyp visibility scores for BLI-bright were not higher than WL for right-sided location, < 10 mm size, sessile serrated adenoma and polyp histology, and poor preparation. For those characteristics, LCI improved the lesions with right-sided location, SSA/P histology, and poor preparation significantly better than BLI.

CONCLUSIONS

 LCI improved polyp visibility compared to WL for both expert and non-expert endoscopists. It is useful for improving polyp visibility in any location, any size, any morphology, any histology, and any preparation level.