| [Background]Gastric cancer is the third leading cause of cancer death in the world.The detection of early-stage gastric neoplastic lesions is associated with improved survival and the potential for complete resection.Gastric cancer is a multistep process that includes the consecutive development of chronic gastritis followed by mucosal atrophy,gastric intestinal metaplasia(GIM),dysplasia,and finally adenocarcinoma.The surveillance of patients with gastric intestinal metaplasia may therefore lead to the earlier detection of advanced precancerous lesions and gastric cancer.The gold standard for diagnosing gastric intestinal metaplasia remains the histology of biopsy specimens.The major limitation of this approach is that gastric intestinal metaplasia shows few macroscopic morphological changes,and thus,may be missed with random biopsy sampling.Recently,several new endoscopic techniques have been developed to increase the detection of GIM,including chromoendoscopy,autofluorescence imaging,confocal laser endomicroscopy,flexible spectral imaging color enhancement,narrow band imaging(NBI)and magnification endoscopy.Currently,there is still no unified standard for chromoendoscopy in the diagnosis of GIM.Moreover,the use of methylene blue carries the risk of causing oxidative DNA damage,while autofluorescence imaging,confocal laser endomicroscopy and flexible spectral imaging color enhancement are hard to manipulate.Therefore,these techniques are not generally used in clinical practice.NBI is an endoscopic imaging technology,which results in the good contrast of surface structures and vascular architecture in the superficial mucosa using blue and green narrow-band light.However,due to the large stomach cavity,the vision is always dark,so it is not obvious advantage to observe the gastric lesions in NBI.NBI with magnification endoscopy can provide a microscopic image of the mucosal and vascular structures,which are useful for the detection of gastric lesions.But magnification is not popular,so it is not practical.Originally,the method of sprinkling acetic acid to delineate lesions was reported by Guelrud et al.Yagi et al.and Tanaka et al.then combined acetic acid with magnification endoscopy for the assessment of gastric neoplasms.The transient white coloration of the epithelial surface,which occurs after the spraying of acetic acid,is a consequence of increased opacity.This corresponds to reversible alteration of tertiary structures of cellular proteins.Yamashita et al.and Sakai et al.reported acetic acid indigo carmine mixture method was useful for detecting the early gastric cancer.Our previous study found that indigo carmine added to acetic acid helps to improve the target biopsy rat in intraepithelial neoplasia and GIM.In this study,we determined whether NBI in combination with acetic acid(AA-NBI)improves the diagnosis of GIM.[Aim]The aim of the present study was to estimate the accuracy of acetic acid enhanced narrow band imaging for the diagnosis of GIM.[Methods]1.The present study was performed in 132 consecutive patients who were 40 years or older and required endoscopic examination from February to June 2016.Exclusion criteria were patients with noticeable advanced gastric cancer,previous gastrectomy or partial gastric resection,on-going treatment with antiplatelet medication,anticoagulant medication or nonsteroidal anti-inflammatory drugs,gastrorrhagia and the presence of hemorrhagic diseases.2.Conventional white-light endoscopy(WLE),NBI and AA-NBI were performed in all patients by the same endoscopist specializing in NBI and WLE endoscopy during a single procedure.First,the esophagus,stomach and duodenum were carefully examined using WLE.Mucus adhering to the mucosa of the gastric antrum and angulus was washed away as thoroughly as possible.All suspicious antral and angular gastric lesions were photographed.Currently,there are no standard criteria for GIM in WLE;therefore,any abnormal mucosal change,such as localized discoloration and rough areas,was considered to be indicative of GIM lesions in this study.The endoscopist used the NBI system to carefully observe the gastric antrum and angulus.After found a suspicious lesion,the endoscopist would move the lens close to the lesion to observe the mucosal pattern using no zoomed endoscopy.All suspicious lesions were photographed.NBI suspicious lesions for GIM were defined as bluish-whitish areas with a regular mucosal pattern.Finally,acetic acid diluted with water(0.6%)was evenly applied to the antrum and angulus areas through the forceps channel in the NBI model.Suspicious GIM lesions were defined as whitish patches with a regular mucosal pattern.It should mention that,during all these practice,another experienced endoscopist confirmed the lesions simultaneously.The positions of the lesions detected by WLE,NBI or AA-NBI were recorded to ensure the precision of the biopsies obtained.At least one targeted biopsy was separately collected from the endoscopic lesions suspected of GIM by AA-NBI or WLE,and two random biopsies were collected from the antrum and angulus in areas where there were no abnormal findings to serve as controls.If no suspected lesions were identified by AA-NBI,NBI and WLE,three random biopsies were obtained in the antrum and angulus according to the updated Sydney classification.[Results]1.WLE had a sensitivity of 33.3%,a specificity of 28.8%,a positive predictive value of 31.9%,a negative predictive value of 30.2%and a accuracy of 31.1%in the diagnosis of GIM.In comparison,AA-NBI showed a sensitivity of 87.9%,a specificity of 68.2%,a positive predictive value of 73.4%,a negative predictive value of 84.9%and a accuracy of 78.0%for the diagnosis of GIM.The sensitivity,specificity,positive predictive values,negative predictive values and accuracy of AA-NBI were all significantly higher than those of WLE(P<0.001)2.In the diagnosis of GIM,NBI had a sensitivity of 66.7%,a specificity of 68.2%,a positive predictive value of 67.7%,a negative predictive value of 67.2%and a accuracy of 67.4%in the diagnosis of GIM.In comparison,AA-NBI showed a sensitivity of 87.9%,a specificity of 68.2%,a positive predictive value of 73.4%,a negative predictive value of 84.9%and a accuracy of 78.0%for the diagnosis of GIM.The sensitivity,negative predictive value of AA-NBI were significantly higher than those of NBI(P<0.05)[Conclusion]The whitish patches observed in the gastric mucosa with AA-NBI are highly accurate indicators for GIM.AA-NBI can improve the accuracy of endoscopy-targeted biopsies for GIM.[Background]Recently,several new endoscopic techniques have been developed to increase the detection of early gastric cancer(EGC).Previously,radical surgical resection of the entire stomach and lymph node dissection were needed for effective therapy.However,the quality of life after gastrectomy is greatly reduced.With the development of endoscopic treatment,EGC can be resected by endoscopic submucosal dissection(ESD).The five year survival rate of EGC after endoscopic resection is similar to that of surgical operation.Because ESD does not change the anatomical structure of patients,and thus does not affect the quality of life.Over the past 20 years,endoscopic mucosal resection(EMR)has been developing to treat EGC.In the guidelines,the lesions measuring less than 2 cm in diameter best fit the above criteria.Improved EMR featuring ESD,which involves cutting of the mucosal around the lesion followed by direct dissection of the submucosal layer,can provide en bloc resection.Currently,ESD is widely accepted treatment for EGC,and it can be performed regardless of tumor size,location,or fibrosis.There has been an increase in number of ESD for EGC and a corresponding increase in the number of en bloc specimens with a positive horizontal margin.For successful outcome,it is necessary to accurately determine the demarcation of EGC.The extent of the lesion in conventional endoscopy is always similar to the surrounding normal mucosal,so it is difficult to accurately judge the demarcation.Yuzo Sakai et al.reported the diagnostic performance rat was 17.0%with conventional endoscopy.Indigo carmine is a deep-blue contrast stain,which is usually used for recognize the demarcation of EGC.However,it is sometimes difficult to recognize the periphery of lesions,especially for superficial or flat-type tumors.Yuzo Sakai et al.reported the diagnostic performance rat was 52.8%with indigo carmine.The use of magnification(ME)for the diagnosis of EGC and EGC demarcation was reported.Nonetheless,we have encountered situations in which EGC demarcations were too subtle to assure diagnosis using conventional ME(CME).Narrow band imaging(NBI)is a video endoscopy imaging technique that enhances the display of microstructures and capillaries in the superficial mucosal layer through the use of narrow band filters that change the spectral feature of observation light relative to that of narrow band filters.Using NBI and ME(NBI-ME)can show clear images of Microvascular and Microsurface on mucosal surfaces.Furthermore,NBI-ME provides a detailed assessment of the extent of EGC.The transient white coloration of the epithelial surface,which occurs after the spraying of acetic acid(AA),is a consequence of increased opacity.This corresponds to reversible alteration of tertiary structures of cellular proteins.In this study,we used ME with a combination of NBI and AA instillation(AA-NBIME)in the determination of the demarcation of EGC,and compared four methods-CME,NBI-ME,AA-ME and AA-NBIME-for ease of recognition of EGC demarcation.[Aim]The aim of the study was to determine whether AA-NBIME improves contrast in images of EGC demarcation,and compared with the other methods-CME,NBI-ME,AA-ME.[Methods]1.This study group included 32 patients with EGC required ESD from September 2015 to March 2016.Exclusion criteria were patients on-going treatment with antiplatelet medication,anticoagulant medication or nonsteroidal anti-inflammatory drugs,gastrorrhagia and the presence of hemorrhagic diseases.2.All procedures were carried out using a GIF-H260Z magnifying endoscopy and a Olympus CV-260SL endoscopic system.A black hood was attached to the tip of the endoscopy to maintain focal distance during the procedure.Following conventional observation,surface mucus was washed away with water in preparation for ME.The endoscope was fixed at one lesion demarcation site and magnified images of the demarcation were recorded using CME,NBI-ME,AA-ME and AA-NBIME.CME was carried out first and an image was saved.The mode was then changed to NBI for capture of an NBI-ME image at the same angle.For AA-ME,20 ml acetic acid was sprinkled onto the lesion at low pressure through the endoscope accessory channel.When gastric mucosa whitened transiently,enhancing the contrast of surface patterns,an AA-ME image was obtained from the same angle.The final imaging mode,AA-NBIME,was applied at the same angle and a fourth at the image was obtained.All patients underwent ESD for treatment of EGC.Several spots were marked 5-10 mm outside of each lesion.Following an injection of saline + indigo carmine + adrenaline into the submucosa,a mucosal incision outside the spots and an exfoliation of the submucosa were made with an IT knife.All specimen were then extend on boards with pins for fixation in 10%formalin.Each lesion,together with the surrounding mucosa,was cut into 2mm wide serial step,section.All specimen were evaluate by the same experienced pathologist.Endoscopic images were randomly allocated to three experts and three non-experts for evaluation.Three experts and three non-experts scored each of the four images of each lesion for ease of recognition of demarcation(lto 4 being easiest).[Results]1.The mean scores of experts judging for images acquired using each technique were:CME 1.5±0.5,NBI-ME 2.7±0.8,AA-ME 2.7±0.6 and AA-NBIME 3.5±0.6.There were significant difference between the mean scores for the four techniques(P<0.001)using one-way repeated-measures ANOVA.In a Bonferroni,s multiple comparison,the average scores of imagines acquired using AA-NBIME were significantly higher than those acquired using other methods.Images acquired by NBI-ME or AA-ME scored significantly higher than those by CME.2.The mean scores of non-experts judging for images acquired using each technique were:CME 1.6±0.5,NBI-ME 2.8±0.9,AA-ME 2.8±0.8 and AA-NBIME 3.5±0.6.There were significant difference between the mean scores for the four techniques(P<0.001)using one-way repeated-measures ANOVA.In a Bonferroni’s multiple comparison,the average scores of imagines acquired using AA-NBIME were significantly higher than those acquired using other methods.Images acquired by NBI-ME or AA-ME scored significantly higher than those by CME.Images acquired by NBI-ME images significantly higher than CME images.[Conclusion]Early gastric cancer demarcations were recognized most easily using AA-NBIME,and more easily using AA-ME or NBI-ME than CME.[Background]Colorectal cancer(CRC)is the third most common cancer and the fourth leading cause of cancer death in the world.It is widely accepted that adenomatous polyps are precursors of colorectal cancer,and their removal significantly reduces the incidence of CRC.It is reported that more than 90%of polyps found by colonoscopy were small polyps or diminutive polyps,and diminutive polyps are dominant.Most of small polyps are non-neoplastic with the majority of these being hyperplastic.Therefore,these polypectomies are unnecessary to perform,posing risks of bleeding and perforation.Therefore,it is very important to differentiate neoplastic from non-neoplastic polyps in real time.Magnification endoscopies in combination with chromoendoscopy have been developed since several years ago.Kudo’s Pit pattern(PP)analysis by magnifying chromoendoscopy is widely used for effective discrimination between neoplastic and non-neoplastic colorectal polyps.However,chromoendoscopy is unpopular with endoscopists due to the long learning curve.What’s more,it’s very operator-dependent and technically hard,requiring extra staining solution.Narrow band imaging(NBI)has been most widely studied for better visualization of the mucosal detail and vascular structures of neoplastic tissues.It’s easy to operate,only needs the push of a button.NBI with magnification endoscopy(ME)can provide a microscopic image of the mucosal and vascular structures,which are useful for the diagnosis of colorectal polyps.However,in terms of diagnostic accuracy on neoplastic lesions,NBIME is inferior to magnifying chromoendoscopy.AA-NBIME has been proposed as an effective method for visualizing the superficial mucosal microstructures of the digestive tract due to the participation of acetic acid.However,the comparison among ME,NBIME and AA-NBIME on the diagnosis of small colorectal polyps has not been fully elucidated.According to Kudo Pit pattern(PP)classification,Endoscopic images were independently reviewed by three experts and three non-experts.We performed this study to compare the diagnostic accuracy and interobserver agreement among ME,NBIME and AA-NBIME.[Aim]The aim of the study was to evaluate the clinical value of magnification endoscopy with acetic acid enhancement and narrow-band imaging in the diagnosis of small colorectal neoplasms.[Methods]1.This study group included 122 patients with 261 polyps(<lcm)required for performing polypectomies from March 2015 to March 2017.We excluded patients from enrolment who had coagulopathy or a platelet count less than 50,000/mm3 or lesions covered with adherent mucus or blood,insufficiently enhanced by the acetic acid.2.All patients were prepared for colonoscopy with 2L of polyethylene glycol-electrolyte solution and dimethicone administered on the morning of the examination.A conventional colonoscope was used firstly for routine colonoscopy.When the colonoscope arrived to ileocecus,reinspect the colon during withdrawal from the cecum.Once a polyp was detected,surface mucus was washed away with water,and optical diagnosis was made using magnification endoscope.Endoscopic images were taken in the following order:Magnification Endoscopy(ME),Magnification endoscopy with narrow-band imaging(NBIME)and Magnification endoscopy with acetic acid(1.5%)-enhanced NBI(AA-NBIME).All polyps were removed by biopsy forceps or Endoscopic Mucosal Resection(EMR)and sent for histological assessment.Endoscopic images were independently reviewed by three experts and three non-experts.The three experts had rich experience in magnification endoscopy in the colorectum and the three non-experts were proficient in conventional colonoscopy,while without any experience in magnifying endoscopy.Images were assessed according to Kudo Pit pattern classification to compare the diagnostic accuracy among three modalities based on Histopathological results.Before starting the study,the non-experts group completed a training session on Kudo Pit pattern classification.In both groups,the accuracy of the modality was included in the study only when two or three members had the same idea on the classification of the lesion.The Kudo Pit pattern classification was as follows:Type I:round pits;Type II:stellar or papillary pits;Type III L:large tubular or roundish pits;Type III S:small tubular or roundish pits;Type IV:branch-like or gyrus-like pits;Type V:non-structural pits.Types I,II were classified as non-neoplastic,whereas types III,IV,V were regarded as neoplastic lesions.Three experts and three non-experts scored each of the three images sharpness of each polyps(lto 4 being most sharpness).[Results]1.For all reviewers in the both groups,the diagnostic sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV)and accuracy of AA-NBIME and NBIME were all significant higher than ME(P<0.001).For three experts,AA-NBIME showed a statistically significantly higher diagnostic accuracy compared to NBIME(P<0.05).For three non-experts,AA-NBIME had a significantly higher sensitivity and accuracy than NBIME(P<0.05).2.The average scores(experts and non-experts)of images acquired using AA-NBIME were significantly higher than those acquired using NBIME and ME(P<0.001).For both groups,scores of images acquired using NBIME were significantly higher than those of ME(P<0.001).3.For the expert group,the kappa values showed "almost perfect" agreement for AA-NBIME,"substantial" agreement for NBIME,and "moderate" agreement for ME.For the non-expert group,the kappa values showed "almost perfect" agreement for AA-NBIME,"moderate" agreement not only for NBIME but also for ME.[Conclusion]AA-NBIME showed statistically significantly higher diagnostic accuracy for colorectal small neoplasms,with good reproducibility,compared with ME and NBIME. |
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