The accuracy of confocal laser endomicroscopy, narrow band imaging, and chromoendoscopy for the detection of atrophic gastritis

Automated classification of ulcerative lesions in small intestine using densenet with channel attention and residual dilated blocks

Objective. Ulceration of the small intestine, which has a high incidence, includes Crohn's disease (CD), intestinal tuberculosis (ITB), primary small intestinal lymphoma (PSIL), cryptogenic multifocal ulcerous stenosing enteritis (CMUSE), and non-specific ulcer (NSU). However, the ulceration morphology can easily be misdiagnosed through enteroscopy.Approach. In this study, DRCA-DenseNet169, which is based on DenseNet169, with residual dilated blocks and a channel attention block, is proposed to identify CD, ITB, PSIL, CMUSE, and NSU intelligently. In addition, a novel loss function that incorporates dynamic weights is designed to enhance the precision of imbalanced datasets with limited samples. DRCA-Densenet169 was evaluated using 10883 enteroscopy images, including 5375 ulcer images and 5508 normal images, which were obtained from the Shanghai Changhai Hospital.Main results. DRCA-Densenet169 achieved an overall accuracy of 85.27% ± 0.32%, a weighted-precision of 83.99% ± 2.47%, a weighted-recall of 84.36% ± 0.88% and a weighted-F1-score of 84.07% ± 2.14%.Significance. The results demonstrate that DRCA-Densenet169 has high recognition accuracy and strong robustness in identifying different types of ulcers when obtaining immediate and preliminary diagnoses.

Confocal Laser Endomicroscopy for Detection of Early Upper Gastrointestinal Cancer

Esophageal and gastric cancers are common diseases with high morbidity and mortality; thus, early detection and treatment are beneficial to improve prognosis. Confocal laser endomicroscopy (CLE) is a novel imaging technique that permits the histological analysis of tissues during endoscopy. CLE has been shown to uniquely affect the diagnosis of early upper gastrointestinal cancers. Relevant literature was searched using PubMed and Google Scholar databases. Despite inherent flaws, CLE can reduce tissue damage and improve diagnostic accuracy to a certain extent. CLE in combination with other imaging methods can help enhance the detection rate and avoid unnecessary biopsies in the management of esophageal or gastric cancer and precancerous lesions. CLE is of great significance in the diagnosis and surveillance of early cancers of the upper gastrointestinal tract. Further technical innovations and the standardisation of CLE will make it more responsive to the needs of routine clinical applications.

A deep learning network based on multi-scale and attention for the diagnosis of chronic atrophic gastritis

BACKGROUND AND STUDY AIM

Chronic atrophic gastritis plays an important role in the process of gastric cancer. Deep learning is gradually introduced in the medical field, and how to better apply a convolutional neural network (CNN) to the diagnosis of chronic atrophic gastritis remains a research hotspot. This study was designed to improve the performance of CNN on diagnosing chronic atrophic gastritis by constructing and evaluating a network structure based on the characteristics of gastroscopic images.

METHODS

Three endoscopists reviewed the endoscopic images of the gastric antrum from the Gastroscopy Image Database of Zhongnan Hospital and labelled available images according to pathological results. Two novel modules proposed recently were introduced to construct the Multi-scale with Attention net (MWA-net) considering the characters of similar medical images. After training the network using images of training sets, the diagnostic ability of the MWA-net was evaluated by comparing it with those of other deep learning models and endoscopists with varying degrees of expertise.

RESULTS

As a result, 5,159 images of the gastric antrum from 2,240 patients were used to train and test the MWA-net. Compared with the direct application of famous networks, the MWA-net achieved the best performance (accuracy, 92.13%) with an increase of 1.80% compared to that of ResNet. The suspicious lesions indicated by the network are consistent with the conclusion of experts. The sensitivity and specificity of the convolutional network for gastric atrophy diagnosis are 90.19% and 94.51%, respectively, which are higher than those of experts.

CONCLUSIONS

Highly similar images of chronic atrophic gastritis can be identified by the proposed MWA-net, which has a better performance than other well-known networks. This work can further reduce the workload of gastroscopists, simplify the diagnostic process and provide medical assistance to more residents.

Newly proposed quantitative criteria can assess chronic atrophic gastritis via probe-based confocal laser endomicroscopy (pCLE): a pilot study

Background and study aims  Probe-based confocal laser endomicroscopy (pCLE) can provide high magnification to evaluate chronic atrophic gastritis (CAG), but the current pCLE criteria are qualitative and prone to variability. We aimed to propose a quantitative CAG criterion based on pCLE to distinguish non-atrophic gastritis (NAG) from CAG. Patients and methods  This observational, exploratory pilot study included patients with NAG and CAG evaluated via esophagogastroduodenoscopy, pCLE, and histology. We measured the gastric glands density, gastric gland area, and inter-glandular distance during pCLE. Results  Thirty-nine patients (30/39 with CAG) were included. In total, 194 glands were measured by pCLE, and 18301 were measured by histology, with a median of five glands per NAG patient and 4.5 per CAG patient; pCLE moderately correlate with histology (rho = 0.307; P  = 0.087). A gland area of 1890-9105 µm ² and an inter-glandular distance of 12 to 72 µm based on the values observed in the NAG patients were considered normal. The proposed pCLE-based CAG criteria were as follows: a) glands density < 5; b) gland area < 1/16 the pCLE field area (< 1890 µm ² ) or > 1/4 the pCLE field area (> 9105 µm ² ); or c) inter-glandular distance < 12 or > 72 µm; CAG was diagnosed by the presence of at least one criterion. The proposed criteria discriminated CAG with a ranged sensitivity of 76.9 % to 92.3 %, a negative predictive value of 66.6 % to 80.0 %, and 69.6 % to 73.9% accuracy. Conclusions  The proposed pCLE criteria offer an accurate quantitative measurement of CAG with high sensitivity and excellent interobserver agreement. Larger studies are needed to validate the proposed criteria.

Confocal Laser Endomicroscopy Can Improve the Diagnosis Rate and Range Assessment of Patients With Conflicting Chronic Atrophic Gastritis Results of White Light Endoscopic and Pathological Diagnosis

Background and Aims

Chronic atrophic gastritis (CAG) is closely related to the development of gastric cancer. However, the diagnostic accuracy of white light endoscopy (WLE) biopsy for CAG is poor. The diagnostic role and efficacy of confocal laser endomicroscopy (CLE) in CAG missed under WLE biopsy remain unclear.

Methods

This study is a single-center prospective study that included 21 patients from 1,349 patients who underwent WLE and biopsy and whose WLE results confirmed CAG, but pathological results did not. Then, all these patients received CLE examination and underwent targeted biopsies and five-point standard biopsies. The sensitivity, specificity, and accuracy of CLE diagnosis and targeted biopsy were analyzed.

Results

The pathological results of five-point standard biopsies in 21 patients confirmed CAG, and 17 patients (81.0%) were confirmed to have intestinal metaplasia (IM). According to the image diagnosis of CLE, there were 19 cases (90.5%) of CAG and 14 cases (66.7%) of IM among these 21 patients. According to the targeted biopsy of CLE, 17 cases (81.0%) of CAG and 14 cases (66.7%) of IM were diagnosed. There was no significant difference between CLE image diagnosis and five-point standard biopsies in terms of atrophy severity score (p = 0.927), IM severity score (p = 0.250), atrophy scope score (p = 0.781), and IM scope score (p = 0.195). For CAG, the sensitivity and accuracy of CLE image diagnosis were higher than those of CLE targeted biopsies (90.5% vs. 81.0%, p = 0.331), but for IM, the diagnosis was the same.

Conclusions

CLE can improve the diagnosis rate of CAG and can increase the comprehensive assessment of the scope and severity of CAG.

Gastric epithelial histology and precancerous conditions

The most common histological type of gastric cancer (GC) is gastric adenocarcinoma arising from the gastric epithelium. Less common variants include mesenchymal, lymphoproliferative and neuroendocrine neoplasms. The Lauren scheme classifies GC into intestinal type, diffuse type and mixed type. The WHO classification includes papillary, tubular, mucinous, poorly cohesive and mixed GC. Chronic atrophic gastritis (CAG) and intestinal metaplasia are recommended as common precancerous conditions. No definite precancerous condition of diffuse/poorly/undifferentiated type is recommended. Chronic superficial inflammation and hyperplasia of foveolar cells may be the focus. Presently, the management of early GC and precancerous conditions mainly relies on endoscopy including diagnosis, treatment and surveillance. Management of precancerous conditions promotes the early detection and treatment of early GC, and even prevent the occurrence of GC. In the review, precancerous conditions including CAG, metaplasia, foveolar hyperplasia and gastric hyperplastic polyps derived from the gastric epithelium have been concluded, based on the overview of gastric epithelial histological organization and its renewal.

Multimodal imaging as optical biopsy system for gastritis diagnosis in humans, and input of the mouse model

BACKGROUND

Gastric inflammation is a major risk factor for gastric cancer. Current endoscopic methods are not able to efficiently detect and characterize gastric inflammation, leading to a sub-optimal patients' care. New non-invasive methods are needed. Reflectance mucosal light analysis is of particular interest in this context. The aim of our study was to analyze reflectance light and specific autofluorescence signals, both in humans and in a mouse model of gastritis.

METHODS

We recruited patients undergoing gastroendoscopic procedure during which reflectance was analysed with a multispectral camera. In parallel, the gastritis mouse model of Helicobacter pylori infection was used to investigate reflectance from ex vivo gastric samples using a spectrometer. In both cases, autofluorescence signals were measured using a confocal microscope.

FINDINGS

In gastritis patients, reflectance modifications were significant in near-infrared spectrum, with a decrease between 610 and 725 nm and an increase between 750 and 840 nm. Autofluorescence was also modified, showing variations around 550 nm of emission. In H. pylori infected mice developing gastric inflammatory lesions, we observed significant reflectance modifications 18 months after infection, with increased intensity between 617 and 672 nm. Autofluorescence was significantly modified after 1, 3 and 6 months around 550 and 630 nm. Both in human and in mouse, these reflectance data can be considered as biomarkers and accurately predicted inflammatory state.

INTERPRETATION

In this pilot study, using a practical measuring device, we identified in humans, modification of reflectance spectra in the visible spectrum and for the first time in near-infrared, associated with inflammatory gastric states. Furthermore, both in the mouse model and humans, we also observed modifications of autofluorescence associated with gastric inflammation. These innovative data pave the way to deeper validation studies on larger cohorts, for further development of an optical biopsy system to detect gastritis and finally to better surveil this important gastric cancer risk factor.

FUNDING

The project was funded by the ANR EMMIE (ANR-15-CE17-0015) and the French Gastroenterology Society (SNFGE).

Comparison of the diagnostic efficacy of blue laser imaging with narrow band imaging for gastric cancer and precancerous lesions: a meta-analysis

BACKGROUND AND AIMS

novel endoscopic techniques including narrowband imaging (NBI) and blue laser imaging (BLI) have led to the improved detection of early stage gastric cancer and precancerous lesions. However, these techniques are not generally thought to be equivalent at present and BLI is generally considered as superior to NBI. Therefore, this comprehensive meta-analysis aimed to definitively compare the diagnostic efficacy of NBI and BLI for the diagnosis of gastric cancer and precancerous lesions.

METHODS

relevant articles were identified via searches of the PubMed, Web of Science, Embase and Cochrane Library databases from their inception until October 2019. In total, 28 relevant studies were identified and incorporated into the meta-analysis. RevMan5.3 was used to assess the relative diagnostic efficacy of these two imaging modalities in these studies. The threshold was assessed using Meta-DiSc 1.4 and STATA 14.0 for bivariate regression modeling of pooled studies.

RESULTS

the pooled sensitivity of BLI for gastric cancer was 0.89 (0.80, 0.95) and the specificity was 0.92 (0.76, 0.98). The pooled sensitivity of NBI for gastric cancer was 0.83 (0.75, 0.89) and the specificity was 0.95 (0.91, 0.97). The pooled sensitivity of BLI for precancerous lesions was 0.81 (0.71, 0.87) and the specificity was 0.90 (0.80, 0.96). The pooled sensitivity of NBI for precancerous lesions was 0.80 (0.75, 0.85) and the specificity was 0.88 (0.77, 0.94).

CONCLUSIONS

this study showed that both BLI and NBI have a very high diagnostic efficacy for the detection of gastric cancer and precancerous lesions, the sensitivity and specificity of these two approaches were similar.

The role of computer-assisted systems for upper-endoscopy quality monitoring and assessment of gastric lesions

This article analyses the literature regarding the value of computer-assisted systems in esogastroduodenoscopy-quality monitoring and the assessment of gastric lesions. Current data show promising results in upper-endoscopy quality control and a satisfactory detection accuracy of gastric premalignant and malignant lesions, similar or even exceeding that of experienced endoscopists. Moreover, artificial systems enable the decision for the best treatment strategies in gastric-cancer patient care, namely endoscopic vs surgical resection according to tumor depth. In so doing, unnecessary surgical interventions would be avoided whilst providing a better quality of life and prognosis for these patients. All these performance data have been revealed by numerous studies using different artificial intelligence (AI) algorithms in addition to white-light endoscopy or novel endoscopic techniques that are available in expert endoscopy centers. It is expected that ongoing clinical trials involving AI and the embedding of computer-assisted diagnosis systems into endoscopic devices will enable real-life implementation of AI endoscopic systems in the near future and at the same time will help to overcome the current limits of the computer-assisted systems leading to an improvement in performance. These benefits should lead to better diagnostic and treatment strategies for gastric-cancer patients. Furthermore, the incorporation of AI algorithms in endoscopic tools along with the development of large electronic databases containing endoscopic images might help in upper-endoscopy assistance and could be used for telemedicine purposes and second opinion for difficult cases.

Advances in the application of artificial intelligence in solid tumor imaging

Early diagnosis and timely treatment are crucial in reducing cancer-related mortality. Artificial intelligence (AI) has greatly relieved clinical workloads and changed the current medical workflows. We searched for recent studies, reports and reviews referring to AI and solid tumors; many reviews have summarized AI applications in the diagnosis and treatment of a single tumor type. We herein systematically review the advances of AI application in multiple solid tumors including esophagus, stomach, intestine, breast, thyroid, prostate, lung, liver, cervix, pancreas and kidney with a specific focus on the continual improvement on model performance in imaging practice.

Diagnosing chronic atrophic gastritis by gastroscopy using artificial intelligence

BACKGROUND

The sensitivity of endoscopy in diagnosing chronic atrophic gastritis is only 42%, and multipoint biopsy, despite being more accurate, is not always available.

AIMS

This study aimed to construct a convolutional neural network to improve the diagnostic rate of chronic atrophic gastritis.

METHODS

We collected 5470 images of the gastric antrums of 1699 patients and labeled them with their pathological findings. Of these, 3042 images depicted atrophic gastritis and 2428 did not. We designed and trained a convolutional neural network-chronic atrophic gastritis model to diagnose atrophic gastritis accurately, verified by five-fold cross-validation. Moreover, the diagnoses of the deep learning model were compared with those of three experts.

RESULTS

The diagnostic accuracy, sensitivity, and specificity of the convolutional neural network-chronic atrophic gastritis model in diagnosing atrophic gastritis were 0.942, 0.945, and 0.940, respectively, which were higher than those of the experts. The detection rates of mild, moderate, and severe atrophic gastritis were 93%, 95%, and 99%, respectively.

CONCLUSION

Chronic atrophic gastritis could be diagnosed by gastroscopic images using the convolutional neural network-chronic atrophic gastritis model. This may greatly reduce the burden on endoscopy physicians, simplify diagnostic routines, and reduce costs for doctors and patients.

Quantitative Diagnosis of Atrophic Gastritis by Probe-Based Confocal Laser Endomicroscopy

Aims

The aims of this study were to characterize nonatrophic and atrophic gastric mucosa under conventional endoscopy and probe-based confocal laser endomicroscopy (pCLE) modes and to define quantitative diagnostic parameters for these lesions under pCLE.

Method

In phase I, 64 patients with gastric mucosal lesions diagnosed by gastrointestinal endoscopy were enrolled in the study. Normal mucosa and suspicious lesions were evaluated under normal white light imaging (WLI) and pCLE mode. Descriptive characteristic of gastric mucosal inflammation and atrophy under pCLE were defined according to the histology. In phase II, the criteria for nonatrophic gastritis (NAG) and chronic atrophic gastritis (CAG) under pCLE were used to diagnose the mucosal lesions in 431 patients. Diagnostic accuracy of each endoscopy modes was evaluated by measuring the concordance with histology.

Result

A total of 64 patients with 187 positions were enrolled in the first part of this study. According to the histological diagnosis, the vessel diameter was increased in the NAG (11.18 ± 0.1 μm) and CAG (13.21 ± 0.29 μm) and CAG (13.21 ± 0.29 μm) and CAG (13.21 ± 0.29 μm) and CAG (13.21 ± 0.29 μm) and CAG (13.21 ± 0.29 μm) and CAG (13.21 ± 0.29 μm) and CAG (13.21 ± 0.29 

Conclusion

pCLE shows high potential for the diagnosis of gastric inflammation and atrophy based on quantitative criteria and has the ability to be a substitute for histology in the diagnosis of diffuse lesions in the stomach.

[Application of probe-based confocal laser endomicroscopy in diagnosis of gastric carcinoma and precancerous lesions]

OBJECTIVE

To assess the application of probe-based confocal laser endomicroscopy (pCLE) in diagnosis of gastric carcinoma and precancerous lesions.

METHODS

Patients underwent pCLE in the First Affiliated Hospital of Zhejiang University School of Medicine during December 2013 and November 2014 and in the First Affiliated Hospital of Zhejiang Chinese Medical University during January 2014 and December 2017 were enrolled. The consistency between pCLE diagnosis and pathological diagnosis of gastric lesions, including atrophic gastritis, gastric intestinal metaplasia, low-grade intraepithelial neoplasia and high-grade intraepithelial neoplasia (including gastric carcinoma) was analyzed.

RESULTS

Totally 154 gastric lesions from 119 patients were detected by pCLE. Using pathological diagnosis as gold standard, the sensitivity, specificity, coincidence rate and κ value of pCLE diagnosis for atrophic gastritis were 94.34%, 91.09%, 92.21%and 0.83; those indicators for gastric intestinal metaplasia were 84.47%, 92.16%, 87.01% and 0.72. The coincidence rate and κ value of pCLE diagnosis of complete gastric intestinal metaplasia were 0.75 and 0.49; for incomplete gastric intestinal metaplasia were 0.79 and 0.48, respectively. The sensitivity, specificity, coincidence rate and κ value of pCLE diagnosis for low-grade intraepithelial neoplasia were 85.29%, 87.50%, 87.01%and 0.66; those for high-grade intraepithelial neoplasia (including gastric carcinoma) were 95.83%, 97.17%, 96.75%and 0.92.

CONCLUSIONS

pCLE can be used for diagnosis of gastric carcinoma and pericancerous lesions and also for typing of gastric intestinal metaplasia.

Near-infrared probe-based confocal microendoscope for deep-tissue imaging

In this work, a near-infrared probe-based confocal microendoscope (pCM) with a 785 nm laser source, a long working distance, and a probe with diameter of 2.6 mm that can be compatible with a conventional endoscope is demonstrated to produce deep-tissue images at cellular resolutions with enhanced contrast and signal-to-noise ratio. Theoretical simulations and experiments confirm that near-infrared light can optimize the image quality. Abundant details of mouse esophagus obtained at different depths demonstrate the system's ability to image deep tissues at cellular resolutions, which makes it possible to diagnose diseases in the digestive tract in real time, laying a solid foundation for clinical applications.

Clinical efficacy and safety of Shenling Baizhu powder as an adjunctive treatment for atrophic gastritis with Helicobacter pylori infection

AIM

To evaluate the clinical efficacy and safety of Shenling Baizhu powder as an adjunctive treatment for atrophic gastritis with Helicobacter pylori (H. pylori) infection.

METHODS

Sixty atrophic gastritis patients with H. pylori infection were selected from January 2016 to October 2016 at the Third Affiliated Hospital of Zhejiang Chinese Medicine University and randomly divided into either an experimental group (n = 30) or a control group (n = 30). The control group was treated with quadruple therapy to eradicate H. pylori, while the experimental group was treated with quadruple therapy plus Shenling Baizhu powder. The patients in both groups were treated for 8 wk. The total effective rates of the two groups were calculated. The scores of main symptoms (including abdominal distension, dry mouth, anorexia, fatigue, and indigestion), endoscopic scores (including mucosa, mucous erosion, bile reflux, mucous folds, and blood vessels), H. pylori eradication rate, and complications (headache, diarrhea, constipation, rash, nausea, and vomiting) were compared between the two groups.

RESULTS

The total effective rate was significantly higher in the experimental group than in the control group (93.33% vs 73.33%, χ² = 4.3221, P = 0.0377). Before treatment, there was no significant difference in abdominal distension, dry mouth, anorexia, fatigue, or indigestion scores between the two groups (P > 0.05); after treatment, these scores were significantly decreased in both groups (P < 0.05), and the decrease was more significant in the experimental group. The eradication rate of H. pylori was significantly higher in the experimental group than in the control group (96.67% vs 80.00%, χ² = 4.0421, P = 0.0444).

CONCLUSION

Shenling Baizhu power is effective in the treatment of atrophic gastritis with H. pylori, and it can significantly reduce the clinical symptoms and improve the clinical changes of mucosal blood flow with good safety.

Shenqi Yiwei decoction for treatment of atrophic gastritis of spleen-stomach deficiency cold type: Clinical efficacy and influence on TXB2 and 6-keto-PGF1α

AIM

To evaluate the clinical efficacy of Shenqi Yiwei decoction in the treatment of atrophic gastritis of spleen-stomach deficiency cold type and investigate its influence on TXB₂ and 6-keto-PGF1α.

METHODS

Eighty-six patients with atrophic gastritis of spleen-stomach deficiency cold type were selected from January 2016 to October 2017 at the Third Affiliated Hospital of Zhejiang Chinese Medicine University, and the patients were randomly divided into either an experimental group (n = 43) or a control group (n = 43). The control group was treated with omeprazole, while the experimental group was treated with Shenqi Yiwei decoction. The patients in both groups were treated for 8 wk. The effective rates of the two groups were compared. Main symptom scores (including abdominal distension, dry mouth, anorexia, fatigue, and indigestion), endoscopic scores (including mucosal appearance, mucosal erosion, bile reflux, mucous folds, and blood vessels), TXB₂ and 6-keto-PGF1α, and complications were also compared between the two groups.

RESULTS

The total effective rate was significantly higher in the experimental group than in the control group (95.35% vs 81.40%, χ² = 4.0741, P = 0.0436). Before treatment, abdominal distension, dry mouth, anorexia, fatigue, and indigestion scores were not statistically significant between the two groups (P > 0.05); after treatment, these scored significantly decreased in both groups (P < 0.05), and the decrease was more significant in the experimental group. Before treatment, scores of mucosal appearance, mucosal erosion, bile reflux, mucous folds, and blood vessels were not statistically significant between the two groups (P > 0.05); after treatment, these scores were significantly improved in both groups (P < 0.05), and the improvement was more significant in the experimental group (P < 0.05). Before treatment, TXB₂ and 6-keto-PGF1α differed significantly between the two groups (P > 0.05); after treatment, TXB₂ decreased significantly and 6-keto-PGF1α increased significantly in both groups (P < 0.05), and the changes were more significant in the experimental group (P < 0.05). Adverse reactions such as constipation and vomiting did not occur in either group.

CONCLUSION

Shenqi Yiwei decoction has a good therapeutic effect in atrophic gastritis of spleen-stomach deficiency cold type, and it can significantly reduce clinical symptoms and improve endoscopic changes possibly by regulating TXB₂ and 6-keto-PGF1α.

Diagnostic performance of confocal laser endomicroscopy for atrophy and gastric intestinal metaplasia: A meta-analysis

OBJECTIVE

To systematically evaluate the diagnostic efficacy of confocal laser endomicroscopy (CLE) for gastric atrophy (GA) and gastric intestinal metaplasia (GIM).

METHODS

Literature search was performed in PubMed and the Cochrane Library for CLE, GA and GIM. The sensitivity, specificity and diagnostic odds ratio (DOR) in diagnosing GA and GIM were pooled for analysis. A summary receiver operating curve (SROC) was documented and the area under the curve was calculated.

RESULTS

Of the 10 studies included in this current analysis, the pooled sensitivity, specificity and DOR of CLE to diagnose GA and GIM were found to be 88%, 98% and 330.85, and 93%, 98% and 439.97, respectively. The area under the SROC were 0.9491 and 0.9812 for the diagnosis of GA and GIM, respectively. Higher sensitivity and specificity of this technique in diagnosing GA and GIM were found in patients without representative disease spectrum and those received pCLE by subgroup analysis.

CONCLUSION

CLE is of great value and may be considered an alternative modality for the early diagnosis of GA and GIM.

The diagnostic value of confocal laser endomicroscopy for gastric cancer and precancerous lesions among Asian population: a system review and meta-analysis

OBJECTIVE

The objective of this study is to evaluate the diagnostic value of confocal laser endomicroscopy (CLE) in detection of gastric cancer (GC), gastric intraepithelial metaplasia (GIM), and gastric intraepithelial neoplasia (GIN) lesions.

METHOD

PubMed, the Cochrane Library, and Wangfang databases were searched to include eligible articles about CLE in detection of gastric lesions. After study selection, quality assessment and data extraction conducted by two reviewers independently, meta-analysis was performed by Meta-Disc 1.4. The pooled sensitivity and specificity was calculated, receiver operating characteristic (ROC) curve was constructed, and the area under ROC curve (AUC) was calculated.

RESULTS

Twenty-three studies evaluating the diagnostic value of CLE were included. For the diagnosis of GC lesions, the pooled sensitivity, specificity, and AUC were 91% (88-94%), 99% (99-99%), and 0.9513, respectively. For the diagnosis of lesions, the pooled sensitivity, specificity, and AUC were 92% (90-94%), 97% (96-98%), and 0.9774, respectively. For the diagnosis of GIN lesions, the pooled sensitivity, specificity and AUC were 81% (75-85%), 98% (97-98%), and 0.9204, respectively.

CONCLUSIONS

CLE can provide an accurate diagnosis with high sensitivity and specificity for GC, GIM, and GIN lesions. The results should be confirmed by well-designed, multi-centered, randomized controlled, and double blinded trials with large samples.

Diagnostic of Helicobacter pylori infection

There is progress in endoscopy techniques. While it is not yet possible to detect Helicobacter pylori directly in the stomach, it becomes easier to detect the mucosal changes induced by the bacteria. Some small changes can also increase the sensitivity of the invasive tests, for example culture or histology, but the wide use of proton-pump inhibitors has a negative impact on these tests. Only molecular methods are able to detect a limited load of bacteria, especially by using real-time PCR but also with new methods, for example dual-priming oligonucleotide-based PCR, loop-medicated isothermal amplification, droplet-digital PCR or a multiple genetic analysis system. Among the noninvasive tests, urea breath test remains a test of major interest, while there are attempts to develop an ammonia breath test and other nanosensor devices. A new antigen stool test, a chemoluminescence immunoassay using the LIAISON apparatus has also been tested for the first time with success. Despite its limitations, serology remains the most popular test to detect H. pylori antibodies. It also allows pepsinogen dosage which is of interest for detecting atrophy.

Confocal Laser Endomicroscopy in Gastrointestinal and Pancreatobiliary Diseases: A Systematic Review and Meta-Analysis

Confocal laser endomicroscopy (CLE) is an endoscopic-assisted technique developed to obtain histopathological diagnoses of gastrointestinal and pancreatobiliary diseases in real time. The objective of this systematic review is to analyze the current literature on CLE and to evaluate the applicability and diagnostic yield of CLE in patients with gastrointestinal and pancreatobiliary diseases. A literature search was performed on MEDLINE, EMBASE, Scopus, and Cochrane Oral Health Group Specialized Register, using pertinent keywords without time limitations. Both prospective and retrospective clinical studies that evaluated the sensitivity, specificity, or accuracy of CLE were eligible for inclusion. Of 662 articles identified, 102 studies were included in the systematic review. The studies were conducted between 2004 and 2015 in 16 different countries. CLE demonstrated high sensitivity and specificity in the detection of dysplasia in Barrett's esophagus, gastric neoplasms and polyps, colorectal cancers in inflammatory bowel disease, malignant pancreatobiliary strictures, and pancreatic cysts. Although CLE has several promising applications, its use has been limited by its low availability, high cost, and need of specific operator training. Further clinical trials with a particular focus on cost-effectiveness and medicoeconomic analyses, as well as standardized institutional training, are advocated to implement CLE in routine clinical practice.

Usefulness and Future Prospects of Confocal Laser Endomicroscopy for Gastric Premalignant and Malignant Lesions

Confocal laser endomicroscopy (CLE) is a new technology enabling endoscopists to visualize tissue at the cellular level. CLE has the fundamental potential to provide a histologic diagnosis, and may theoretically replace or reduce the need for performing biopsy for histology. The clinical benefits of CLE are more obvious in esophageal disease, including Barrett's esophagus. Currently, this technology has been adapted to the diagnosis and surveillance of Barrett's esophagus and related neoplasia. Standard white light endoscopy is the primary tool for gastric cancer screening. Currently, the only method available to precisely diagnose these lesions is upper endoscopy with an appropriate biopsy. A recent study showed that CLE could characterize dysplasia or cancer and identify the risk factors for gastric cancer, such as intestinal metaplasia and the presence of Helicobacter pylori in vivo, although fewer studies on CLE were performed on the stomach than on Barrett's esophagus and other esophageal diseases. However, the application of CLE to routine clinical endoscopy continues to be refined. This review focused on the usefulness and future prospects of CLE for gastric premalignant and malignant lesions.

Magnifying narrow-band imaging endoscopy is superior in diagnosis of early gastric cancer

AIM: To evaluate the diagnostic effectiveness of white light endoscopy, magnifying endoscopy (ME), and magnifying narrow-band imaging endoscopy (ME-NBI) in detecting early gastric cancer (EGC).

METHODS: From March 2010 to June 2012, a total of 3616 patients received screening for gastric cancer by magnifying endoscopy. There were 3675 focal gastric lesions detected using conventional high definition white light endoscopy (HD-WLE) in four different referential hospitals that were recruited for further investigation using ME and ME-NBI. The images obtained from HD-WLE, ME, and ME-NBI were reviewed by four experienced endoscopists to evaluate their diagnostic effectiveness for EGC. The diagnosis of cancerous and non-cancerous lesions was conducted by evaluating the microvascular and microsurface patterns using the VS classification system. The final endoscopic diagnosis of each lesion was determined by consultation when a disagreement occurred. We used histopathological results as the gold standard for the diagnosis of EGC.

RESULTS: Among the 3675 lesions found, 1508 were validated by pathological findings as chronic gastritis, 1279 as chronic gastritis with intestinal metaplasia, 631 as low-grade neoplasia, and 257 as EGC. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of HD-WLE for the diagnosis of EGC were 71.2%, 99.1%, 85.5%, 97.9% and 97.1%, respectively. The results of ME for diagnosing EGC were 81.3%, 98.8%, 83.3%, 98.6% and 97.6%, respectively. The results of ME-NBI for the diagnosis of EGC were 87.2%, 98.6%, 82.1%, 99.0% and 97.8%, respectively. The diagnostic sensitivity and accuracy of paired ME and ME-NBI were significantly better than those of HD-WLE (P < 0.05).

CONCLUSION: HD-WLE has a relatively high accuracy for diagnosing EGC and is an effective screening tool. Further investigations of ME and ME-NBI are required to achieve superior accuracy.

Characterization of lesions in the stomach: will confocal laser endomicroscopy replace the pathologist?

Confocal laser endomicroscopy (CLE) permits microscopic visualization of the mucosa during endoscopy at an approximately 1000fold magnification, permitting endoscopists to obtain microscopic analysis during gastroscopy. This can result in optimized diagnosis of diffuse alterations such as gastric atrophy and intestinal metaplasia and may limit the sampling error of untargeted biopsies. It also allows risk stratification prior to endoscopic therapy of neoplastic lesions of the stomach. In these areas, CLE represents a valuable adjunct for targeted histopathology. In addition, CLE allows on-site in vivo imaging, and by this insight into physiologic and pathophysiologic as well as molecular events of the stomach without major artifacts.