Could near focus endoscopy,narrow-band imaging,and acetic acid improve the visualization of microscopic features of stomach mucosa?

BACKGROUND Conventional magnifying endoscopy with narrow-band imaging(NBI)observation of the gastric body mucosa shows dominant patterns in relation to the regular arrangement of collecting venules,subepithelial capillary network,and gastric pits.AIM To evaluate the effectiveness of a new one-dual(near)focus,NBI mode in the assessment of the microscopic features of gastric body mucosa compared to conventional magnification.METHODS During 2021 and 2022,68 patients underwent proximal gastrointestinal endoscopy using magnification endoscopic modalities subsequently applying acetic acid(AA).The GIF-190HQ series NBI system with dual focus capability was used for the investigation of gastric mucosa.At the time of the endoscopy,the gastric body mucosa of all enrolled patients was photographed using the white light endoscopy(WLE),near focus(NF),NF-NBI,AA-NF,and AA-NF-NBI modes.RESULTS The WLE,NF and NF-NBI endoscopic modes for all patients(204 images)were classified in the same order into three groups.Two images from each patient for the AA-NF and AA-NF-NBI endoscopic modes were classified in the same order.According to all three observers who completed the work independently,NF magnification was significantly superior to WLE(P<0.01),and the NF-NBI mode was significantly superior to NF magnification(P<0.01).After applying AA,the three observers confirmed that AA-NF-NBI was significantly superior to AA-NF(P<0.01).Interobserver kappa values for WLE were 0.609,0.704,and 0.598,respectively and were 0.600,0.721,and 0.637,respectively,for NF magnification.For the NF-NBI mode,the values were 0.378,0.471,and 0.553,respectively.For AA-NF,they were 0.453,0.603,and 0.480,respectively,and for AA-NF-NBI,they were 0.643,0.506,and 0.354,respectively.CONCLUSION When investigating gastric mucosa in microscopic detail,NF-NBI was the most powerful endoscopic mode for assessing regular arrangement of collecting venules,subepithelial capillary network,and gastric pits among the five endoscopic modalities investigated in this study.AA-NF-NBI was the most powerful endoscopic mode for analyzing crypt opening and intervening part.

A Novel Sensing Imaging Equipment Under Extremely Dim Light for Blast Furnace Burden Surface:Starlight High-Temperature Industrial Endoscope

Blast furnace(BF)burden surface contains the most abundant,intuitive and credible smelting information and acquiring high-definition and high-brightness optical images of which is essential to realize precise material charging control,optimize gas flow distribution and improve ironmaking efficiency.It has been challengeable to obtain high-quality optical burden surface images under high-temperature,high-dust,and extremelydim(less than 0.001 Lux)environment.Based on a novel endoscopic sensing detection idea,a reverse telephoto structure starlight imaging system with large field of view and large aperture is designed.Combined with a water-air dual cooling intelligent self-maintenance protection device and the imaging system,a starlight high-temperature industrial endoscope is developed to obtain clear optical burden surface images stably under the harsh environment.Based on an endoscope imaging area model,a material flow trajectory model and a gas-dust coupling distribution model,an optimal installation position and posture configuration method for the endoscope is proposed,which maximizes the effective imaging area and ensures large-area,safe and stable imaging of the device in a confined space.Industrial experiments and applications indicate that the proposed method obtains clear and reliable large-area optical burden surface images and reveals new BF conditions,providing key data support for green iron smelting.

A Comprehensive Study on the digestive Endoscopic Technique and Narrow-Band Imaging for Early Gastric Cancer Screening

Objective:To explore the implementation of gastrointestinal endoscopy technology and endoscopic narrow-band imaging(NBI)in the early screening of gastric cancer and to observe and study their application effects.Methods:During the period from March 2023 to August 2023,312 patients who received gastroscopy in the Kunming Guandu District People’s Hospital were selected,and they underwent both conventional gastroscopy and endoscopic NBI,with clinicopathological tissue biopsy serving as the gold standard.The application value for early screening of gastric cancer was observed and analyzed.Results:The scoring data showed that the clarity of gastric mucosal glandular tube structure,microvascular structure clarity,and lesion contour scoring data of conventional gastroscopy were lower than those of the NBI technology(P<0.05).The screening rate of pathological biopsy in 312 patients was 18.59%(58 cases).Conventional gastroscopy showed a screening rate of 11.53%(36 cases),while NBI technology examined a screening rate of 17.63%(55 cases),and the two-by-two comparison of the screening rate data of the three groups was not statistically significant(P>0.05).The sensitivity,specificity,accuracy,positive predictive value,and negative predictive value of conventional gastroscopy appeared to be lower than those of NBI technology(P<0.05).Conclusion:In the early screening of gastric cancer,endoscopic NBI technology can be applied to patients.Compared with conventional gastroscopy,it provides a clearer visualization of the structure of the gastric mucosal glandular structure and microvascular structure,with a certain screening rate.Additionally,its sensitivity,specificity,accuracy,positive predictive value,and negative predictive value are higher,demonstrating outstanding effectiveness.

Topic highlight on texture and color enhancement imaging in gastrointestinal diseases

Olympus Corporation developed texture and color enhancement imaging(TXI)as a novel image-enhancing endoscopic technique.This topic highlights a series of hot-topic articles that investigated the efficacy of TXI for gastrointestinal disease identification in the clinical setting.A randomized controlled trial demonstrated improvements in the colorectal adenoma detection rate(ADR)and the mean number of adenomas per procedure(MAP)of TXI compared with those of white-light imaging(WLI)observation(58.7%vs 42.7%,adjusted relative risk 1.35,95%CI:1.17-1.56;1.36 vs 0.89,adjusted incident risk ratio 1.48,95%CI:1.22-1.80,respectively).A cross-over study also showed that the colorectal MAP and ADR in TXI were higher than those in WLI(1.5 vs 1.0,adjusted odds ratio 1.4,95%CI:1.2-1.6;58.2%vs 46.8%,1.5,1.0-2.3,respectively).A randomized controlled trial demonstrated non-inferiority of TXI to narrow-band imaging in the colorectal mean number of adenomas and sessile serrated lesions per procedure(0.29 vs 0.30,difference for non-inferiority-0.01,95%CI:-0.10 to 0.08).A cohort study found that scoring for ulcerative colitis severity using TXI could predict relapse of ulcerative colitis.A cross-sectional study found that TXI improved the gastric cancer detection rate compared to WLI(0.71%vs 0.29%).A cross-sectional study revealed that the sensitivity and accuracy for active Helicobacter pylori gastritis in TXI were higher than those of WLI(69.2%vs 52.5%and 85.3%vs 78.7%,res-pectively).In conclusion,TXI can improve gastrointestinal lesion detection and qualitative diagnosis.Therefore,further studies on the efficacy of TXI in clinical practice are required.

Optical scanning endoscope via a single multimode optical fiber

Optical endoscopy has become an essential diagnostic and therapeutic approach in modern biomedicine for directly observing organs and tissues deep inside the human body,enabling non-invasive,rapid diagnosis and treatment.Optical fiber endoscopy is highly competitive among various endoscopic imaging techniques due to its high flexibility,compact structure,excellent resolution,and resistance to electromagnetic interference.Over the past decade,endoscopes based on a single multimode optical fiber(MMF)have attracted widespread research interest due to their potential to significantly reduce the footprint of optical fiber endoscopes and enhance imaging capabilities.In comparison with other imaging principles of MMF endoscopes,the scanning imaging method based on the wavefront shaping technique is highly developed and provides benefits including excellent imaging contrast,broad applicability to complex imaging scenarios,and good compatibility with various well-established scanning imaging modalities.In this review,various technical routes to achieve light focusing through MMF and procedures to conduct the scanning imaging of MMF endoscopes are introduced.The advancements in imaging performance enhancements,integrations of various imaging modalities with MMF scanning endoscopes,and applications are summarized.Challenges specific to this endoscopic imaging technology are analyzed,and potential remedies and avenues for future developments are discussed.

Diagnostic performance of narrow-band imaging international colorectal endoscopic and Japanese narrow-band imaging expert team classification systems for colorectal cancer and precancerous lesions

BACKGROUND In recent years,two new narrow-band imaging(NBI)classifications have been proposed:The NBI international colorectal endoscopic(NICE)classification and Japanese NBI expert team(JNET)classification.Most validation studies of the two new NBI classifications were conducted in classification setting units by experienced endoscopists,and the application of use in different centers among endoscopists with different endoscopy skills remains unknown.AIM To evaluate clinical application and possible problems of NICE and JNET classification for the differential diagnosis of colorectal cancer and precancerous lesions.METHODS Six endoscopists with varying levels of experience participated in this study.Eighty-seven consecutive patients with a total of 125 lesions were photographed during non-magnifying conventional white-light colonoscopy,non-magnifying NBI,and magnifying NBI.The three groups of endoscopic pictures of each lesion were evaluated by the six endoscopists in randomized order using the NICE and JENT classifications separately.Then we calculated the six endoscopists’sensitivity,specificity,accuracy,positive predictive value,and negative predictive value for each category of the two classifications.RESULTS The sensitivity,specificity,and accuracy of JNET classification type 1 and 3 were similar to NICE classification type 1 and 3 in both the highly experienced endoscopist(HEE)and less-experienced endoscopist(LEE)groups.The specificity of JNET classification type 1 and 3 and NICE classification type 3 in both the HEE and LEE groups was>95%,and the overall interobserver agreement was good in both groups.The sensitivity of NICE classification type 3 lesions for diagnosis of SM-d carcinoma in the HEE group was significantly superior to that in the LEE group(91.7%vs 83.3%;P=0.042).The sensitivity of JNET classification type 2B lesions for the diagnosis of high-grade dysplasia or superficial submucosal invasive carcinoma in the HEE and LEE groups was 53.8%and 51.3%,respectively.Compared with other types of JNET classification,the diagnostic ability of type 2B was the weakest.CONCLUSION The treatment strategy of the two classification type 1 and 3 lesions can be based on the results of endoscopic examination.JNET type 2B lesions need further examination.

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 referentialhospitals 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.

Narrow-band imaging with magnifying endoscopy is accurate for detecting gastric intestinal metaplasia

AIM:To investigate the predictive value of narrowband imaging with magnifying endoscopy (NBI-ME) for identifying gastric intestinal metaplasia (GIM) in unselected patients. METHODS:We prospectively evaluated consecutive patients undergoing upper endoscopy for various indications, such as epigastric discomfort/pain, anaemia, gastro-oesophageal reflux disease, suspicion of peptic ulcer disease, or chronic liver diseases. Patients underwent NBI-ME, which was performed by three blinded, experienced endoscopists. In addition, five biopsies (2 antrum, 1 angulus, and 2 corpus) were taken and examined by two pathologists unaware of the endoscopic findings to determine the presence or absence of GIM. The correlation between light blue crest (LBC) appearance and histology was measured. Moreover, we quantified the degree of LBC appearance as less than 20% (+), 20%-80% (++) and more than 80% (+++) of an image field, and the semiquantitative evaluation of LBC appearance was correlated with IM percentage from the histological findings. RESULTS:We enrolled 100 (58 F/42 M) patients who were mainly referred for gastro-esophageal reflux disease/dyspepsia (46%), cancer screening/anaemia (34%), chronic liver disease (9%), and suspected celiac disease (6%); the remaining patients were referred for other indications. The prevalence of Helicobacter pylori (H. pylori ) infection detected from the biopsies was 31%, while 67% of the patients used proton pump inhibitors. LBCs were found in the antrum of 33 patients (33%); 20 of the cases were classified as LBC+, 9 as LBC++, and 4 as LBC+++. LBCs were found in the gastric body of 6 patients (6%), with 5 of them also having LBCs in the antrum. The correlation between the appearance of LBCs and histological GIM was good, with a sensitivity of 80% (95%CI:67-92), a specificity of 96% (95%CI:93-99), a positive predictive value of 84% (95%CI:73-96), a negative predictive value of 95% (95%CI:92-98), and an accuracy of 93% (95%CI:90-97). The NBI-ME examination overlooked GIM in 8 cases, but the GIM was less than 5% in 7 of the cases. Moreover, in the 6 false positive cases, the histological examination showed the presence of reactive gastropathy (4 cases) or H. pylori active chronic gastritis (2 cases). The semiquantitative correlation between the rate of LBC appearance and the percentage of GIM was 79% (P < 0.01). CONCLUSION:NBI-ME achieved good sensitivity and specificity in recognising GIM in an unselected population. In routine clinical practice, this technique can reliably target gastric biopsies.

Standard vs magnifying narrow-band imaging endoscopy for diagnosis of Helicobacter pylori infection and gastric precancerous conditions

BACKGROUND Advances in endoscopic imaging enable the identification of patients at high risk of gastric cancer.However,there are no comparative data on the utility of standard and magnifying narrow-band imaging(M-NBI)endoscopy for diagnosing Helicobacter pylori(H.pylori)infection,gastric atrophy,and intestinal metaplasia.AIM To compare the diagnostic performance of standard and M-NBI endoscopy for H.pylori gastritis and precancerous conditions.METHODS In 254 patients,standard endoscopy findings were classified into mosaic-like appearance(type A),diffuse homogenous redness(type B),and irregular redness with groove(type C).Gastric mucosal patterns visualized by M-NBI were classified as regular round pits with polygonal sulci(type Z-1),more dilated and linear pits without sulci(type Z-2),and loss of gastric pits with coiled vessels(type Z-3).RESULTS The diagnostic accuracy of standard and M-NBI endoscopy for H.pylori gastritis was 93.3%and 96.1%,respectively.Regarding gastric precancerous conditions,the accuracy of standard and M-NBI endoscopy was 72.0%vs 72.6%for moderate to severe atrophy,and 61.7%vs.61.1%for intestinal metaplasia in the corpus,respectively.Compared to type A and Z-1,types B+C and Z-2+Z-3 were significantly associated with moderate to severe atrophy[odds ratio(OR)=5.56 and 8.67]and serum pepsinogen I/II ratio of≤3(OR=4.48 and 5.69).CONCLUSION Close observation of the gastric mucosa by standard and M-NBI endoscopy is useful for the diagnosis of H.pylori gastritis and precancerous conditions.

Narrow-band imaging endoscopy to assess mucosal angiogenesis in inflammatory bowel disease: A pilot study

AIM: To investigate whether narrow band imaging (NBI) is a useful tool for the in vivo detection of angiogenesis in inflammatory bowel disease (IBD) patients. METHODS: Conventional and NBI colonoscopy was performed in 14 patients with colonic inflammation (8 ulcerative colitis and 6 Crohn’s disease). Biopsy samples were taken and CD31 expression was assayed immuno- histochemically; microvascular density was assessed by vessel count. RESULTS: In areas that were endoscopically normal but positive on NBI, there was a significant (P < 0.05) increase in angiogenesis (12 ± 1 vessels/field vs 18 ± 2 vessels/field) compared with areas negative on NBI. In addition, in areas that were inflamed on white light endoscopy and positive on NBI, there was a significant (P < 0.01) increase in vessel density (24 ± 7 vessels/f ield) compared with NBI-negative areas.CONCLUSION: NBI may allow in vivo imaging of intestinal angiogenesis in IBD patients.

Diagnostic utility of narrow-band imaging endoscopy for pharyngeal superfi cial carcinoma

AIM: To investigate the endoscopic features of pharyngeal superfi cial carcinoma and evaluate the utility of narrow-band imaging (NBI) for this disease. METHODS: In the present prospective study, 335 patients underwent conventional white light (CWL) en-doscopy and non-magnifi ed/magnifi ed NBI endoscopy, followed by an endoscopic biopsy, for 445 superfi cial lesions in the oropharynx and hypopharynx. The macroscopic appearance of superfi cial lesions was categorized as either elevated (< 5 mm in height), flat, or depressed (not ulcerous). Superficial carcinoma (SC) was defi ned as a superfi cial lesion showing high-grade dysplasia or squamous cell carcinoma on histology. The color, delineation, and macroscopic appearances of the lesions were evaluated by CWL endoscopy. The ratio of the brownish area/intervascular brownish epithelium (IBE), as well as microvascular proliferation, dilation, and irregularities, was determined by non-magnifi ed/ magnifi ed NBI endoscopy. An experienced pathologist who was unaware of the endoscopic fi ndings made the histological diagnoses. By comparing endoscopic fi ndings with histology, we determined the endoscopic features of SC and evaluated the diagnostic utility of NBI. RESULTS: The 445 lesions were divided histologically into two groups: a non-SC group, including non-neoplasia and low-grade dysplasia cases, and an SC group. Of the 445 lesions examined, 333 were classified as non-SC and 112 were classif ied as SC. There were no significant differences in age, gender, or the location of the lesions between the patients in the two groups. The mean diameter of the SC lesions was signif icantly greater than that of non-SC lesions (11.0 ± 7.6 mm vs 4.6 ± 3.6 mm, respectively, P < 0.001). Comparisons of CWL endoscopy fi ndings for SC and non-SC lesions by univariate analysis revealed that the incidence of redness (72% vs 41%, respectively, P < 0.001) and a flat or depressed type of lesion (58% vs 44%, respectively, P = 0.013) was significantly higher in the SC group. Using non-magnifi ed NBI endoscopy, the incidence of a brownish area was signifi cantly higher for SC lesions (79% vs 57%, respectively, P < 0.001). On magnifi ed NBI endoscopy, the incidence of IBE (68% vs 33%, P < 0.001) and microvascular proliferation (82% vs 51%, P < 0.001), dilation (90% vs 76%, P =0.002), and irregularity (82% vs 31%, P < 0.001) was also signifi cantly higher for the SC compared with the non-SC lesions. Multivariate analysis revealed that the incidence of redness (P = 0.022) on CWL endoscopy and IBE (P < 0.001) and microvascular irregularities (P < 0.001) on magnif ied NBI endoscopy was signif icantly higher in SC than non-SC lesions. Redness alone exhibited signifi cantly higher sensitivity and signifi cantly lower specifi city for the diagnosis of SC compared with redness plus IBE and microvascular irregularities (72% vs 52%, P = 0.002; and 59% vs 92%, P < 0.001, respectively). The accuracy of redness plus IBE and irregularities for the diagnosis of SC was signifi cantly greater than using redness alone (82% vs 62%, respectively, P < 0.001). CONCLUSION: Redness, IBE, and microvascular irregularities appear to be closely related to SC lesions. Magnifi ed NBI endoscopy may increase the diagnostic accuracy of CWL endoscopy for SC.

Diagnostic performance of magnifying narrow-band imaging for early gastric cancer: A meta-analysis

AIM: To investigate the performance of magnifying endoscopy with narrow-band imaging(ME-NBI) in the diagnosis of early gastric cancer(EGC).METHODS: Systematic literature searches were conducted until February 2014 in Pub Med, EMBASE, Web of Science, Ovid, Scopus and the Cochrane Library databases by two independent reviewers. Meta-analysis was performed to calculate the pooled sensitivity, specificity and diagnostic odds ratio and to construct a summary receiver operating characteristic(ROC) curve. Subgroup analyses were performed based on the morphology type of lesions, diagnostic standard, the size of lesions, type of assessment, country and sample size to explore possible sources of heterogeneity. A Deeks' asymmetry test was used to evaluate the publication bias.RESULTS: Fourteen studies enrolling 2171 patients were included. The pooled sensitivity, specificity and diagnostic odds ratio for ME-NBI diagnosis of EGC were 0.86(95%CI: 0.83-0.89), 0.96(95%CI: 0.95-0.97) and 102.75(95%CI: 48.14-219.32), respectively, with the area under ROC curve being 0.9623. Among the 14 studies, six also evaluated the diagnostic value of conventional white-light imaging, with a sensitivityof 0.57(95%CI: 0.50-0.64) and a specificity of 0.79(95%CI: 0.76-0.81). When using "VS"(vessel plus surface) ME-NBI diagnostic systems in gastric lesions of depressed macroscopic type, the pooled sensitivity and specificity were 0.64(95%CI: 0.52-0.75) and 0.96(95%CI: 0.95-0.98). For the lesions with a diameter less than 10 mm, the sensitivity and specificity were 0.74(95%CI: 0.65-0.82) and 0.98(95%CI: 0.97-0.98).CONCLUSION: ME-NBI is a promising endoscopic tool in the diagnosis of early gastric cancer and might be helpful in further target biopsy.

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% vs4.15%, 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.

Effect of pronase as mucolytic agent on imaging quality of magnifying endoscopy

AIM:To investigate the efficacy of premedication with pronase,a proteolytic enzyme,in improving imagequality during magnifying endoscopy.METHODS:The study was of a blinded,randomized,prospective design.Patients were assigned to groups administered oral premedication of either pronase and simethicone(Group A)or simethicone alone(Group B).First,the gastric mucosal visibility grade(1-4)was determined during conventional endoscopy,and then a magnifying endoscopic examination was conducted.The quality of images obtained by magnifying endoscopy at the stomach and the esophagus was scored from1 to 3,with a lower score indicating better visibility.The endoscopist used water flushes as needed to obtain satisfactory magnifying endoscopic views.The main study outcomes were the visibility scores during magnifying endoscopy and the number of water flushes.RESULTS:A total of 144 patients were enrolled,and data from 143 patients(M:F=90:53,mean age 57.5 years)were analyzed.The visibility score was significantly higher in the stomach following premedication with pronase(73%with a score of 1 in Group A vs 49%in Group B,P<0.05),but there was no difference in the esophagus visibility scores(67%with a score of 1in Group A vs 58%in Group B).Fewer water flushes[mean 0.7±0.9 times(range:0-3 times)in Group A vs 1.9±1.5 times(range:0-6 times)in Group B,P<0.05]in the pronase premedication group did not affect the endoscopic procedure times[mean 766 s(range:647-866 s)for Group A vs 760 s(range:678-854 s)for Group B,P=0.88].The total gastric mucosal visibility score was also lower in Group A(4.9±1.5 vs 8.3±1.8in Group B,P<0.01).CONCLUSION:The addition of pronase to simethicone premedication resulted in clearer images during magnifying endoscopy and reduced the need for water flushes.

Magnetic endoscopic imaging vs standard colonoscopy:Meta-analysis of randomized controlled trials

AIM:To assess the theoretical advantages of magnetic endoscope imaging(MEI)over standard colonoscopies(SCs)and to compare their efficacies.METHODS:Electronic databases,including PubMed,EMBASE,the Cochrane library and the Science Citation Index,were searched to retrieve relevant trials.In addition,abstracts from papers presented at professional meetings and the reference lists of retrieved articles were reviewed to identify additional studies.The metaanalyses were performed using RevMan 5.1.A random effect model with the Mantel-Haenszel method was used for pooling dichotomous and continuous data.A sensitivity analysis was performed by excluding the trials with a small number of patients and by excluding the trials performed by inexperienced providers.RESULTS:Eight randomized controlled trials(RCTs),including 2967 patients,were included in the metaanalysis to compare cecal intubation rates and times,sedation dose,abdominal pain scores and the use of ancillary maneuvers between MEI and SC.The overall OR was 1.92(95%CI:1.13-3.27,eight RCTs),as indicated by the cecal intubation rate of MEI compared with SC,but MEI did not have any distinct advantage over SC for cecal intubation time(MD=-0.07,95%CI:-0.16-0.02;three RCTs).MEI did not generally result in lower pain scores.Outcomes were also analyzed for the two subgroups based on the endoscopists’experience level to evaluate cecal intubation rates.MEI presented better outcomes for non-experienced colonoscopists than experienced colonoscopists.CONCLUSION:The real-time magnetic imaging system is of benefit in training and educating inexperienced endoscopists and improves the cecal intubation rate for experienced and inexperienced endoscopists.

Linear endoscopic ultrasonography vs magnetic resonance imaging in ampullary tumors

AIM:To assess linear endoscopic ultrasound (L-EUS) and magnetic resonance imaging (MRI) in biliary tract dilation and suspect small ampullary tumor.METHODS:L-EUS and MRI data were compared in 24 patients with small ampullary tumors;all with subsequent histological confirmation.Data were collected prospectively and the accuracy of detection,histological characterization and N staging were assessed retrospectivelyusing the results of surgical or endoscopic treatment as a benchmark.RESULTS:A suspicion of ampullary tumor was present in 75% of MRI and all L-EUS examinations,with 80% agreement between EUS and histological findings at endoscopy.However,L-EUS and histological TN staging at surgery showed moderate agreement (κ=0.54).CONCLUSION:L-EUS could be a useful adjunct as a diagnostic tool in the evaluation of patients with sus-pected ampullary tumors.

Effectiveness of narrow-band imaging magnification for invasion depth in early colorectal cancer

AIM: To evaluate the surface microvascular patterns of early colorectal cancer (ECC) using narrow-band imaging (NBI) with magnification and its effectiveness for invasion depth diagnosis. METHODS: We studied 112 ECC lesions [mucosal/ submucosal superficial (m/sm-s), 69; sm-deep (sm-d), 43] ≥ 10 mm that subsequently underwent endoscopic or surgical treatment at our hospital. We compared microvascular architecture revealed by NBI with magnification to histological findings and then to magnifi- cation colonoscopy pit pattern diagnosis. RESULTS: Univariate analysis indicated vessel density: non-dense (P < 0.0001); vessel regularity: negative (P < 0.0001); caliber regularity: negative (P < 0.0001); vessel length: short (P < 0.0001); and vessel meandering: positive (P = 0.002) occurred significantly more often with sm-d invasion than m/sm-s invasion. Multivariate analysis showed sm-d invasion was independently associated with vessel density: non-dense[odds ratio (OR) = 402.5, 95% confidence interval (CI): 12.4-13 133.1] and vessel regularity: negative (OR = 15.9, 95% CI: 1.2-219.1). Both of these findings when combined were an indicator of sm-d invasion with sensitivity, specificity and accuracy of 81.4%, 100% and 92.9%, respectively. Pit pattern diagnosis sensitivity, specificity and accuracy, meanwhile, were 86.0%, 98.6% and 93.8%, respectively, thus, the NBI with magnification findings of non-dense vessel density and negative vessel regularity when combined together were comparable to pit pattern diagnosis. CONCLUSION: Non-dense vessel density and/or negative vessel regularity observed by NBI with magnification could be indicators of ECC sm-d invasion.

Narrow-band imaging observation of colorectal lesions using NICE classification to avoid discarding significant lesions

AIM: To assess the risk of failing to detect diminutive and small colorectal cancers with the "resect and discard" policy.METHODS: Patients who received colonoscopy and polypectomy were recruited in the retrospective study. Probable histology of the polyps was predicted by six colonoscopists by the use of NICE classification. The incidence of diminutive and small colorectal cancersand their endoscopic features were assessed. RESULTS: In total, we found 681 cases of diminutive(1-5 mm) lesions in 402 patients and 197 cases of small(6-9 mm) lesions in 151 patients. Based on pathology of the diminutive and small polyps, 105 and 18 were non-neoplastic polyps, 557 and 154 were low-grade adenomas, 18 and 24 were high-grade adenomas or intramucosal/submucosal(SM) scanty invasive carcinomas, 1 and 1 were SM deeply invasive carcinoma, respectively. The endoscopic features of invasive cancer were classified as NICE type 3 endoscopically.CONCLUSION: The risk of failing to detect diminutive and small colorectal invasive cancer with the "resect and discard" strategy might be avoided through the use of narrow-band imaging observation with the NICE classification scheme and magnifying endoscopy.

Comparative study on artificial intelligence systems for detecting early esophageal squamous cell carcinoma between narrow-band and white-light imaging

BACKGROUND Non-magnifying endoscopy with narrow-band imaging(NM-NBI)has been frequently used in routine screening of esophagus squamous cell carcinoma(ESCC).The performance of NBI for screening of early ESCC is,however,significantly affected by operator experience.Artificial intelligence may be a unique approach to compensate for the lack of operator experience.AIM To construct a computer-aided detection(CAD)system for application in NMNBI to identify early ESCC and to compare it with our previously reported CAD system with endoscopic white-light imaging(WLI).METHODS A total of 2167 abnormal NM-NBI images of early ESCC and 2568 normal images were collected from three institutions(Zhongshan Hospital of Fudan University,Xuhui Hospital,and Kiang Wu Hospital)as the training dataset,and 316 pairs of images,each pair including images obtained by WLI and NBI(same part),were collected for validation.Twenty endoscopists participated in this study to review the validation images with or without the assistance of the CAD systems.The diagnostic results of the two CAD systems and improvement in diagnostic efficacy of endoscopists were compared in terms of sensitivity,specificity,accuracy,positive predictive value,and negative predictive value.RESULTS The area under receiver operating characteristic curve for CAD-NBI was 0.9761.For the validation dataset,the sensitivity,specificity,accuracy,positive predictive value,and negative predictive value of CAD-NBI were 91.0%,96.7%,94.3%,95.3%,and 93.6%,respectively,while those of CAD-WLI were 98.5%,83.1%,89.5%,80.8%,and 98.7%,respectively.CAD-NBI showed superior accuracy and specificity than CAD-WLI(P=0.028 and P≤0.001,respectively),while CAD-WLI had higher sensitivity than CAD-NBI(P=0.006).By using both CAD-WLI and CAD-NBI,the endoscopists could improve their diagnostic efficacy to the highest level,with accuracy,sensitivity,and specificity of 94.9%,92.4%,and 96.7%,respectively.CONCLUSION The CAD-NBI system for screening early ESCC has higher accuracy and specificity than CAD-WLI.Endoscopists can achieve the best diagnostic efficacy using both CAD-WLI and CAD-NBI.

Endocytoscopic narrow-band imaging efficiency for evaluation of inflammatory activity in ulcerative colitis

AIM:To assess the efficacy of endocytoscopic narrowband imaging(EC-NBI)for evaluating the severity of inflammation in ulcerative colitis(UC).METHODS:This retrospective study was conducted at a single tertiary care referral center.We included UC patients who underwent colonoscopy with endocytoscopy from July 2010 to December 2013.ECNBI was performed,and the images were evaluated by assessing visibility,increased vascularization,and the increased calibers of capillaries and were classified as Obscure,Visible or Dilated.Obscure was indicative of inactive disease,while Visible and Dilated were indicative of acute inflammation.This study received Institutional Review Board approval.The primary outcome measures included the diagnostic ability of EC-NBI to distinguish between active and inactive UC on the basis of histological activity.The conventional endoscopic images were classified according to the Mayo endoscopic score.A score of 0 or 1 indicated inactive disease,whereas a score of 2 indicated active disease.RESULTS:Fifty-two patients were enrolled.There was a strong correlation between the EC-NBI findings and the histological assessment(r=0.871,P<0.01).The sensitivity,specificity,positive predictive value,negative predictive value,and accuracy of EC-NBI for diagnosing acute inflammation were 84.0%,100%,87.1%,100%,and 92.3%,respectively,while those for the Mayo endoscopic score were 100%,40.7%,100%,61.0%,and 69.2%,respectively.Compared with conventional endoscopy,EC-NBI was superior in diagnostic specificity,negative predictive value,and accuracy(P<0.001,P=0.001 and P=0.047,respectively).CONCLUSION:The EC-NBI finding of capillaries in the rectal mucosa was strongly correlated with histological inflammation and aided in the differential diagnosis between active and inactive UC.