Magnifying chromoendoscopy for the detection of premalignant gastrointestinal lesions

The prognosis for patients with malignancies of the gastrointestinal tract is strictly dependent on the early detection of premalignant and malignant lesions. At present, endoscopy can be performed with new, powerful high-resolution or magnifying endoscopes. Comparable to the rapid development in chip technology, the optic features of the newly designed endoscopes offer resolutions that allow new mucosal surface details to be seen. In conjunction with chromoendoscopy, the newly discovered tool of video endoscopy is much easier to use and more impressive than previously used fibreoptic endoscopy. This review summarises the value of magnifying endoscopy in the upper and lower gastrointestinal tract and focuses on gastroesophageal reflux disease and early gastric and colorectal cancer.     

FUTURE PERSPECTIVES OF GASTROINTESTINAL ENDOSCOPY AND JOINT ACADEMIC–INDUSTRIAL RESEARCH FOLLOWING TECHNOLOGICAL INNOVATION IN MEDICAL AND BIOLOGICAL ENGINEERING

Screening surveys conducted to predict the future of gastrointestinal endoscopy, have revealed a tendency towards emphasis on the development of endoscopes of smaller diameters, to reduce the pain and discomfort caused to patients. It appears that the efforts to develop newer endoscopes with a focus on further reducing the diameter of the tip of the endoscopes, while preserving the visualizing and manipulating capabilities of endoscopes, are moving towards development of wireless capsule endoscopes. Regarding improvement in the diagnostic capabilities of endoscopes, it is expected that high‐definition (HD)‐TV technology‐compatible endoscopy systems and so on, will be developed in the near future, with the improved resolution of images and improved image analysis systems, accompanied by the development of new endoscope‐linked devices, such as endoscopic ultrasonography, a fluorescent endoscope, and an ultra‐magnifying endoscope. These developments may eventually lead to the age of ‘bioendoscopy’, in which endoscopes would be used for not only morphological diagnosis, like conventional endoscopes, but also for evaluation of the pathophysiology of individual diseases through combining cell‐level diagnosis with functional diagnosis using an ultra‐magnifying endoscope. This paper will also summarize the current status and problems pertaining to joint academic‐industrial research for the development of new diagnostic imaging devices from an international perspective, placing emphasis on the ideal mode of academic–industry collaboration, improvements in education and personnel development, strengthening of collaboration among the medical, engineering and pharmaceutical fields, and promotion of clinical trials on new medical devices.     

Endoscopic detection of early lower gastrointestinal cancer

The prognosis for patients with malignancies of the lower gastrointestinal tract is strictly dependent on early detection of premalignant and malignant lesions. What should an ideal screening and surveillance colonoscopy be able to accomplish? The technique should allow detection of large but also discrete mucosal alterations. Ideally, endoscopic discrimination between neoplastic and non-neoplastic lesions would be possible during the ongoing procedure. At present, endoscopy can be performed with powerful new endoscopes. Comparable to the rapid development in chip technology, the optical features of the newly designed endoscopes offer resolutions, which allow new surface details to be seen. In conjunction with chromoendoscopy, the newly discovered tool video colonoscopy is much easier and more impressive today than with the previously used fibre-optic endoscopes. Recently, new endoscopic technologies such as narrow band imaging, endocytoscopy, or confocal laser endoscopy have allowed the discovery of a whole new world of image details which will surely improve the diagnostic yield in the field of early malignancies. This review summarises newly available technologies and clinical data about the diagnosis of early lower gastrointestinal cancers.     

Technology insight: Laser-scanning confocal microscopy and endocytoscopy for cellular observation of the gastrointestinal tract

Recent advances in endoscopic imaging technology have enabled the visualization of early-stage cancer and its precursors in the gastrointestinal tract. Chromoendoscopy, magnifying endoscopy, endoscopic optical coherent tomography, spectroscopy, and various combinations of these technologies, are all important for the recognition of small and unclear lesions. To observe cancer cells in vivo, two types of ultra-high magnifying endoscope--'laser-scanning confocal endoscopy series' and 'contact endoscopy series'--that have a maximum of more than 1,000x magnifying power have been developed. These endoscopes can generate high-quality images of both living cancer cells and normal cells in the gastrointestinal tract, with a quality comparable to that possible with conventional cytology. These novel imaging technologies may make in vivo histological diagnosis by virtual histology possible.     

Perspectives of chromo and magnifying endoscopy: how, how much, when, and whom should we stain?

The goal of every routine endoscopy in the gut is the early diagnosis of malignant and premalignant changes of the mucosa. Chromo- and magnifying endoscopes are exciting new tools and offer detailed analysis of the colonic mucosal surface and pit pattern architecture. This review summarizes recent advances in endoscopic characterization of colorectal lesions using magnification endoscopy and chromoendoscopy. Surface analysis of the colon using chromoendoscopy allows a prediction between non-neoplastic and neoplastic lesions with high specificity. The precise delineation of the borders and a more detailed macroscopic analysis of the lesions are further advantages. In particular, flat adenomas and early depressed cancers are now more frequently recognized in western countries suggesting that significant lesions were overlooked by conventional endoscopy in the past. Furthermore, chromoendoscopy can be used in a targeted fashion to screen for sporadic adenomas. Finally, in surveillance colonoscopy, patients with long-standing ulcerative colitis have a valuable benefit if targeted biopsies are performed to detect intraepithelial neoplasias after pan-chromoendoscopy with methylene blue. Although there is a long learning curve, chromoendoscopy should thus belong to every endoscopists armamentarium. However, detailed knowledge about the technique, dyes, and specific staining patterns are mandatory before the yield of screening or surveillance colonoscopy can be increased. The new detailed images seen with magnifying chromoendoscopy are unequivocally the beginning of a new era where new optical developments will allow a unique look on cellular structures.     

Novel endoscopic imaging techniques toward in vivo observation of living cancer cells in the gastrointestinal tract

Recent advances in endoscopic imaging technology have enabled the visualization of cellular-level microstructures of early-stage cancer and its precursors. Chromoendoscopy, magnifying endoscopy, endoscopic optical coherent tomography (EOCT) spectroscopy, and various combinations of these technologies, are all important for the recognition of small and unclear lesions. In order to observe cancer cells in vivo two types of ultra-high magnifying endoscope--'laser-scanning confocal laser-scanning endoscopy series' and 'contact endoscopy series'--that have a maximum of >1,000 times magnifying power have been developed. The use of these endoscopes has allowed the generation of high quality images of both living cancer cells and normal cells in the gastrointestinal tract. In particular, clear images of cells and their nuclei, equivalent to the high quality that is possible with conventional cytology, have been produced. These novel imaging technologies may make in vivo histological diagnosis by virtual histology possible.     

Chromoendoscopy and magnifying endoscopy in patients with gastroesophageal reflux disease. Useful or negligible?

Gastroesophageal reflux disease (GERD) is common in the Western world. Upper endoscopy is needed to characterize the disease. Barrett's esophagus as a complication of GERD is an established precancerous condition which can lead to adenocarcinoma in the distal esophagus. This review summarizes recent advances in the endoscopic characterization of Barrett's esophagus using magnification endoscopy and chromoendoscopy. Methylene blue, indigo carmine and acetic acid are commonly used dyes to facilitate diagnosis of Barrett's esophagus. Methylene blue is absorbed in the specialized columnar epithelium, which is pathognomonic for Barrett's esophagus. Indigo carmine and acetic acid are used as contrast stains to highlight the surface architecture. Currently, different dyes are used in conjunction with magnifying endoscopes to characterize specific surface patterns of Barrett's epithelium. However, the current proposed classifications are too complex relative to their clinical value. Nevertheless, simplification of these systems will occur over time with increased use of magnifying chromoendoscopy. The value of magnifying chromoendoscopy for clinical practice is not determined yet and currently under investigation. However, these techniques have significant potential to improve diagnostic accuracy in patients with Barrett's esophagus.     

ANGIOGENESIS IN SUPERFICIAL ESOPHAGEAL SQUAMOUS CELL CARCINOMA: MAGNIFYING ENDOSCOPIC OBSERVATION AND MOLECULAR ANALYSIS

Observations of esophageal squamous cell carcinoma using magnifying endoscopy have now been carried out extensively and, as a result, it has become clear that the morphology of the microvessels evident at the tumor surface reflects the depth of tumor invasion. In M1 and M2 cancer, the surface microvasculature reveals dilation and elongation of the intrapapillary capillary loops (IPCL). However, at this stage, some immature capillaries resembling IPCL also arise inside the tumor and, therefore, the view of the microvasculature should be described as one showing ‘intermixing of modified IPCL and IPCL‐like immature capillaries (IPCL‐like abnormal capillary)’. As cancer invades into the muscularis mucosa (M3 or deeper), an obviously dilated and irregularly branched tumor‐specific vasculature, more accurately described as ‘neovasculature’, can be observed. From our magnifying endoscopy observations and studies of the molecular profile of early esophageal cancer, we conclude that two major angiogenic steps exist in precancerous and M3 lesions in the early phase of cancer progression. In addition, it is now possible to study cell morphology using an endocytoscope with a much higher magnification (×400–×1000) than magnifying endoscopes currently on the market. The histology revealed in this way may reduce the need for conventional biopsy histology in the future.     

Chromoendoscopy and other novel imaging techniques

The newly developed high-resolution and magnification endoscopes offer features that allow more and new mucosal details to be seen. They are commonly used in conjunction with chromoendoscopy. The analysis of mucosal surface details is beginning to resemble histologic examination. More accurate recognition of small flat and depressed neoplastic lesions is possible. Endoscopic prediction of neoplastic and nonneoplastic tissue is possible by analysis of surface architecture of the mucosa, which influences the endoscopic management. For the diagnosis of flat adenomas, chromoendoscopy should be a part of the endoscopist's armamentarium. In inflammatory bowel disease, chromoendoscopy can be used for patients with long-standing UC to unmask flat intraepithelial neoplasia and is likely to become the new standard method for surveillance colonoscopy in the near future. The new detailed images seen with magnifying chromoendoscopy are the beginning of a new era in which advances in optical development, such as confocal endomicroscopy, allow a unique look at detailed cellular structures.     

Endoscopic microanatomy of the normal gastrointestinal mucosa with narrow band technology and magnification

The development of high-definition endoscopes with optical zoom, along with the use of the digital chromoendoscopy and staining, has given endoscopists the possibility to study the microanatomy of the gastrointestinal mucosa in vivo. The recognition of the changes in the microstructure of the surface and microvascular architecture such as those that occur in neoplastic lesions allow us to characterize these lesions in order to decide on the best course of clinical action. The current greater availability of endoscopes with optical zoom in western countries has allowed the use of this technology in routine clinical practice to spread. In this article we review the basic concepts of magnifying endoscopy and the normal endoscopic microanatomy of the oesophageal, gastric, duodenal, ileal and colonic mucosa.     

MAGNIFYING RATIO and RESOLUTION OF ELECTRONIC ENDOSCOPES

Olympus has been continuing to improve the resolution of its endoscope with each generation developed, and recently it commercialized highly practical magnifying endoscopes such as GIF‐Q24 0Z and CF‐Q240Z. However, the magnifying ratio and resolution of an endoscope are not defined officially by academic conferences. In addition, there is no united definition agreed among endoscope manufacturers. This document aims to explain the definitions of magnifying ratio, maximum magnifying ratio, resolution, and maximum resolution of electronic endoscopes, based on the definitions used by Olympus.     

Magnifying endoscopy with narrow band imaging for predicting the invasion depth of superficial esophageal squamous cell carcinoma

The invasion depth of superficial esophageal squamous cell carcinoma is important in determining therapeutic strategy. The aim of this study was to prospectively investigate the clinical utility of magnifying endoscopy with narrow band imaging compared with that of non‐magnifying high‐resolution endoscopy or high‐frequency endoscopic ultrasonography in predicting the depth of superficial esophageal squamous cell carcinoma. The techniques were carried out in 72 patients with 101 superficial esophageal squamous cell carcinomas, which were then resected by either endoscopic mucosal resection or esophagectomy. The histological invasion depth was divided into two: mucosal or submucosal carcinoma. We investigated the relationship between endoscopic staging and histology of tumor depth. Non‐magnifying high‐resolution endoscopy, magnifying endoscopy with narrow band imaging, and high‐frequency endoscopic ultrasonography had overestimation/underestimation rates of 7/5, 4/4 and 8/3%, respectively. The sensitivity rates for the three techniques were 72, 78, and 83%, respectively, and the specificity rates were 92, 95, and 89%, respectively. There were no statistically significant differences among the three endoscopic techniques. Clinical utility of magnifying endoscopy with narrow band imaging does not seem to be significantly different from that of non‐magnifying high‐resolution endoscopy or high‐frequency endoscopic ultrasonography in predicting the depth of superficial esophageal squamous cell carcinoma. Magnifying endoscopy with narrow band imaging may have potential to reduce overestimation risks of non‐magnifying high‐resolution endoscopy or high‐frequency endoscopic ultrasonography.     

Documento de posicionamiento de la AEG,la SEED y la SEAP sobre calidad de la endoscopia digestiva alta para la detección y vigilancia de las lesiones precursoras de cáncer gástrico

This position paper, sponsored by the Asociación Española de Gastroenterología [Spanish Association of Gastroenterology], the Sociedad Española de Endoscopia Digestiva [Spanish Gastrointestinal Endoscopy Society] and the Sociedad Española de Anatomía Patológica [Spanish Anatomical Pathology Society], aims to establish recommendations for performing an high quality upper gastrointestinal endoscopy for the screening of gastric cancer precursor lesions (GCPL) in low-incidence populations, such as the Spanish population. To establish the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We obtained a consensus among experts using a Delphi method. The document evaluates different measures to improve the quality of upper gastrointestinal endoscopy in this setting and makes recommendations on how to evaluate and treat the identified lesions. We recommend that upper gastrointestinal endoscopy for surveillance of GCPL should be performed by endoscopists with adequate training, administering oral premedication and use of sedation. To improve the identification of GCPL, we recommend the use of high definition endoscopes and conventional or digital chromoendoscopy and, for biopsies, NBI should be used to target the most suspicious areas of intestinal metaplasia. Regarding the evaluation of visible lesions, the risk of submucosal invasion should be evaluated with magnifying endoscopes and endoscopic ultrasound should be reserved for those with suspected deep invasion. In lesions amenable to endoscopic resection, submucosal endoscopic dissection is considered the technique of choice.     

高清晰放大胃镜对幽门螺杆菌相关性胃炎胃粘膜表现的临床研究

目的：研究高清晰放大胃镜下幽门螺杆菌（Hp）相关性胃炎胃粘膜的特点，观察Hp感染根除治疗后胃粘膜的变化。方法：使用Fujinon EG485ZH85万像素高清晰放大电子胃镜，对50例门诊病例经常规胃镜检查后转换高清晰放大功能，详细观察胃体和胃窦粘膜的微细结构，判断Hp感染情况。结果：50例中Hp阳性26例，普通胃镜判断Hp感染的敏感性为34.62％，准确性为58.00％，阳性拟然比为2.08，阴性拟然比为0.78；高清晰放大胃镜判断Hp感染的敏感性为69.23％，准确性为78.00％，阳性拟然比为5.54，阴性拟然比为0.35。两种胃镜检查的Kappa值分别为0.176和0.563。结论：Hp相关性胃炎的胃镜下表现主要是胃小凹不均匀发红，小凹变粗、变宽，集合静脉的模糊、混乱或消失。高清晰放大胃镜判断Hp感染的准确性明显高于普通胃镜。     

MAGNIFYING ENDOSCOPIC OBSERVATION OF THE UPPER GASTROINTESTINAL TRACT

Recent advances in technology enable us to obtain more detailed information during endoscopic procedures. Diagnosis of the pit pattern or microvascular architecture allow the earlier detection of neoplastic lesions in the gastrointestinal tract. These advances have led to the enhanced selection of appropriate treatments. Cancers that are discovered at an early stage can be treated by mucosal resection, whereas advanced cancers are treated with surgery. Recently, some groups have tried to acquire direct in vivo histological images of gastrointestinal mucosa (virtual histology or optical biopsy). Now optical coherence tomography (OCT), confocal laser endoscopy and endo‐cytoscopy systems enable this conception. However, none of these techniques has been proven, although some investigators have been able to use them to enhance cancer detection, and have reported the usefulness of these techniques. The present review assesses the strengths and weaknesses of these technologies, and describes the magnifying observations of the upper gastrointestinal tract using magnifying endoscopy equipment available on the market as well as newly developed endo‐cytoscopy systems. Published and unpublished data for this review were identified by searches of MEDLINE, Register of Cancer Trials: National Cancer Institute ( http://cancertrials.nci.nih.gov/ ) and references from relevant articles. We also contacted researchers. The authors’ own database of references was also used. The search items were as follows: magnifying endoscopy, endo‐cytoscopy system, confocal endoscopy, optical coherence tomography, contact endoscopy, esophageal cancer, Barrett’s esophagus, Barrett’s esophageal cancer, gastric cancer, colon cancer, chromoendoscopy, methylene blue etc.     

COVID-19 and gastrointestinal endoscopies: Current insights and emergent strategies

A new coronavirus emerged in December 2019 in Wuhan city of China, named as the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), and the disease was called coronavirus disease-2019 (COVID-19). The infection due to this virus spread exponentially throughout China and then spread across >205 nations, including the United States (US). Gastrointestinal (GI) endoscopies are routinely performed in the US and globally. Previous reports of isolated infection outbreaks were reported with endoscopes acting as potential vectors. While multidrug-resistant organisms have been reported to be spread by endoscopes, few cases of viruses such as hepatitis B and C are noted in the literature. COVID-19 is predominately spread by droplet transmission, although recent evidence has showed that shedding in feces and feco-oral transmission could also be possible. It is unclear if COVID-19 could be transmitted by endoscopes, but it could theoretically happen due to contact with mucous membranes and body fluids. GI endoscopies involve close contact with oral and colonic contents exposing endoscopy staff to respiratory and oropharyngeal secretions. This can increase the risk of contamination and contribute to virus transmission. Given these risks, all major GI societies have called for rescheduling elective non-urgent procedures and perform only emergent or urgent procedures based on the clinical need. Furthermore, pre-screening of all individuals prior to endoscopy is recommended. This article focuses on the risk of COVID-19 transmission by GI shedding, the potential role of endoscopes as a vector of this novel virus, including transmission during endoscopies, and prevention strategies including deferral of elective non-urgent endoscopy procedures.     

Further validation of magnifying chromocolonoscopy for differentiating colorectal neoplastic polyps in a health screening center

BACKGROUND AND AIM: The accuracy of conventional colonoscopy to differentiate neoplastic and non-neoplastic polyps is limited, justifying a biopsy for histologic analysis. Magnifying chromocolonoscopy has emerged as the best tool available for differentiating adenomatous and hyperplastic polyps during colonoscopy; however, magnifying endoscopes are rarely used in endoscopy units. This study aimed to further validate the effectiveness of magnifying chromocolonoscopy in the diagnosis of neoplastic colorectal polyps in a screening center. METHOD: Five hundred average-risk subjects were randomly divided into two groups: a magnifying chromocolonoscopy group and a conventional chromocolonoscopy group, each of 250 subjects. Lesions were analyzed according to Kudo's classification of pit pattern (types I-V) and additionally subdivided into non-neoplastic (types I-II) and neoplastic (types III-V). Lesions judged as neoplastic were resected and those judged as non-neoplastic were left in situ. Only lesions < or =10 mm were included in the study. Resected lesions were analyzed with histopathological examination. RESULTS: The overall accuracy of magnifying chromocolonoscopy for differentiating neoplastic lesions (95%, 135 of 142), was significantly higher than that of conventional chromocolonoscopy (84%, 102 of 122; P < 0.01). The accuracy of magnifying chromocolonoscopy for differentiating neoplastic lesions < or =5 mm was 94% (135 of 142), whereas that of conventional chromocolonoscopy was only 78% (69 of 89; P < 0.001). Results were not affected by the macroscopic types. CONCLUSION: Magnifying chromocolonoscopy is superior to conventional chromocolonoscopy for the diagnosis of colorectal neoplastic lesions in the setting of a health testing center.     

Narrow-band imaging system with magnifying endoscopy for superficial esophageal lesions

BACKGROUND: By assessing the intrapapillary capillary loop in esophageal mucosa, magnifying endoscopy can play an important role in the evaluation of superficial esophageal lesions. A newly developed narrow-band imaging system was applied to magnifying endoscopy in a clinical setting; the benefit of the narrow-band imaging system was evaluated. METHODS: Forty-one patients (37 men, 4 women; mean age 63.5 [7.3] years) were enrolled between March 2002 and January 2003 in the study. Endoscopy was performed with a magnifying endoscope, a standard video-endoscopic system, and a narrow-band imaging system. The assessment consisted of 3 phases: a numerical analysis of the red, green, blue color value of endoscopic images, creation of model images, and assessment on the actual images. In the numerical analysis, the red, green, blue color value for intrapapillary capillary loop and background mucosa were obtained, and the ratio and contrast value were calculated. RESULTS: In the numerical analysis, both the ratio and the contrast value between the intrapapillary capillary loop and background mucosa were statistically different. Based on an evaluation of created model images, almost all assessors found the narrow-band imaging system to be superior. In the assessment of actual images, the narrow-band imaging system improved overall accuracy for depth of invasion, especially for inexperienced endoscopists. CONCLUSIONS: The narrow-band imaging system improved the accuracy of magnifying endoscopy for assessment of esophageal lesion.     

Minimal change esophagitis: prospective comparison of endoscopic and histological markers between patients with non-erosive reflux disease and normal controls using magnifying endoscopy

INTRODUCTION: More than half the patients with gastroesophageal reflux disease (GERD) show no endoscopic abnormality or minimal change esophagitis (non-erosive reflux disease, NERD). We investigated the value of endoscopic and histological markers for the prediction of NERD before and after treatment with 20 mg esomeprazole. METHODS: Between July and October 2002, consecutive patients presenting for upper endoscopy were stratified into GERD and non-reflux patients (control group) with the help of a questionnaire. The endoscopist was blind to the presence of reflux symptoms. Using magnifying endoscopes minimal change esophagitis was defined by the presence of vascular injection or vascular spots above the Z-line, villous mucosal surface and islands of squamous cell epithelium below the Z-line. Targeted and random biopsies were taken below and above the Z-line. Patients with endoscopically visible classical signs of esophagitis (Los Angeles A-D) or histologically proven Barrett's esophagus were not further investigated in the study (drop out). The esophageal specimens were histologically evaluated for erosions, infiltration with leukocytes, hyperplasia of basal cells and length of papillae. Patients with NERD were treated with 20 mg esomeprazole/day for 4 weeks and reevaluated by endoscopy as described before. RESULTS: 39 patients with heartburn and 39 patients without reflux symptoms (controls) were finally included in the analysis (per protocol). Patients with NERD significantly (p = 0.005) more often showed endoscopic signs of minimal change esophagitis (27/39) than the control group (8/39). An increased length of papillae (14/39 versus 2/39; p = 0.005) and basal cell hyperplasia (17/39 versus 4/39; p = 0.009) were significantly more common in the heartburn group. After treatment with esomeprazole, no significant endoscopic or histological differences between the NERD and control group could be observed. CONCLUSIONS: Minimal change esophagitis can be seen with high resolution magnifying endoscopy. By combining endoscopic and histological markers NERD can be predicted with a sensitivity of 62% and a specificity of 74%. Treatment with esomeprazole for 4 weeks reverses the slight alterations to normal.     

The study of dynamic chemical magnifying endoscopy in gastric neoplasia

BACKGROUND: We assessed the usefulness of acetic acid-enhanced magnifying endoscopy in the diagnosis of gastric neoplasia. METHODS: Forty-five patients (27 men, 18 women; median age 61.6 years) with gastric carcinoma or adenoma were enrolled in a prospective trial of enhanced magnifying endoscopy after instillation of 1.5% acetic acid. Acetic acid-enhanced magnified views of carcinoma or adenoma and the surrounding non-neoplastic mucosa were observed, and the duration of whitening time of each lesion was recorded. OBSERVATIONS: Magnified views of carcinoma showed a minute, grain-like pattern that differed from the surrounding noncancerous mucosa. The histopathologic diagnostic criteria were based on the Vienna classification of GI epithelial neoplasia. The mean duration of whitening differed with each histologic type: low-grade adenoma, 94 seconds; high-grade adenoma, 24.3 seconds; noninvasive carcinoma, 20.1 seconds; invasive intramucosal carcinoma, 3.5 seconds; and submucosal carcinoma or beyond, 2.5 seconds. The duration in the non-neoplastic surrounding mucosa was 90 seconds. After the disappearance of whitening in the carcinoma, the irregular pattern of the carcinoma reappeared, and the contrast between carcinomatous microvessels and the whitened non-neoplastic tissue became very clear on magnifying endoscopy. In accordance with the duration of whitening, more than 1 minute was termed "continuous whitening," from 31 to 60 seconds was "delayed disappearance of whitening," from 30 to 6 seconds was "early disappearance of whitening," and 0 to 5 seconds was "no response." CONCLUSIONS: Acetic acid-enhanced magnifying endoscopy was useful for the diagnosis of gastric adenocarcinoma. The duration of whitening differed among grades of neoplasia, and it was possible to observe changes in the whitening with time. Acetic acid-enhanced magnifying endoscopy, therefore, can be termed "dynamic chemical magnifying endoscopy."