Endocytoscopic Classification Research Articles

Feasibility of new-generation endocytoscopy for the real-time diagnosis of ampullary lesions: A pilot study (with video).

An early and accurate diagnosis of ampullary neoplasia is crucial; however, sampling bias is still a major concern. New-generation endocytoscopy enables real-time visualization of cellular structures and enables an accurate pathological prediction; however, its feasibility for small ampullary lesions has never been investigated. We developed a novel endocytoscopic (EC) classification system for ampullary lesions after an expert review and agreement from five experienced endoscopists and one pathologist. We then consecutively enrolled a total of 43 patients with an enlarged ampulla (<3cm), all of whom received an endocytoscopic examination. The feasibility of endocytoscopy was evaluated, and the performance of the EC classification system was then correlated with the final histopathology. In five cases (11.6%), the endocytoscope could not approach the ampulla, and these cases were defined as technical failure. Among the remaining 38 patients, 8 had histopathology-confirmed adenocarcinoma, 15 had adenoma, and 15 had non-neoplastic lesions. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the EC classification system to diagnose ampullary neoplasias were 95.7%, 86.7%, 91.7%, 92.9%, and 92.1%, respectively. Moreover, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the EC classification to diagnose ampullary cancer were 62.5%, 100%, 100%, 90.9%, and 92.1%, respectively. One case with intra-ampullary papillary-tubular carcinoma was classified as having a non-neoplastic lesion by endocytoscopy. Endocytoscopy and the novel EC classification system demonstrated good feasibility to discriminate ampullary neoplasias from non-neoplastic lesions and may be useful for optical biopsies of clinically suspicious ampullary lesions.

A new classification for the diagnosis of superficial non-ampullary duodenal epithelial tumors using endocytoscopy: A prospective study.

Although the frequency of endoscopic diagnosis of superficial non-ampullary duodenal epithelial tumors (SNADETs) has been increasing in recent years, no criteria for the endoscopic diagnosis of these tumors have been established yet. The aim of this study was to assess the usefulness of endocytoscopy for diagnosis SNADETs and to establish new criteria. This prospective study was conducted at the NTT Medical Center Tokyo from May 2019 to July 2020, and a total of 100 consecutive SNADETs were enrolled. All the endocytoscopic images of the lesions and surrounding normal mucosa were classified into three groups according to the degree of structural atypia and the nuclear morphology and size. The endocytoscopic diagnoses using endocytoscopic classification was compared with the final histopathological diagnoses. Data of 93 patients with 98 lesions were included in the analysis. The preoperative diagnosis by endocytoscopy coincided with the final histopathological diagnosis in 85 (86.7%) of 98 SNADETs. In addition, the sensitivity and specificity for VCL 4/5 were 87.7% and 85.4%, respectively. In contrast, the accuracy, sensitivity, and specificity of preoperative diagnosis by biopsy were 64.3%, 50.9%, and 82.9%, respectively. Preoperative diagnosis by endocytoscopy showed significantly superior accuracy and sensitivity as compared with preoperative biopsy diagnosis (P<0.001, respectively). This new classification (endocytoscopic classification) allows prediction of the tumor histopathology in real time, during endocytoscopy without biopsy, and is expected to be of help in determining the appropriate therapeutic strategies for individual cases of SNADETs. (Clinical trial registration number: UMIN000038643.).

Endocytoscopy Is Useful for the Diagnosis of Superficial Nonampullary Duodenal Epithelial Tumors

Introduction: Endoscopic criteria for the diagnosis of superficial nonampullary duodenal epithelial tumors (SNADETs) are lacking. The aim of this study was to explore the usefulness of endocytoscopy (ECS) in the duodenum. Methods: A total of 77 ECS images stained by methylene blue and 58 images with double staining of methylene blue and crystal violet were obtained from 20 patients. Images were classified into 3 grades based on nuclear and villi atypia: EC A, B, and C. Diagnostic performance of ECS classification to predict histology and interobserver agreement was evaluated. The performance was compared between staining methods and ×520 or ×936 zoom. Results: With methylene blue staining, high rates of accuracy, sensitivity, specificity, and positive predictive value (PPV) over 90% were achieved for tumor and nontumor diagnosis as assessed by EC A versus EC B. High rates of accuracy, sensitivity, PPV, and negative predictive value over 90% were achieved for the differentiation between the diagnosis of the Vienna category 3 and 4/5 as assessed by EC B versus C. The accuracy rate of interpreting ECS images with ×936 zoom among 10 endoscopists was 82%, and the interobserver agreement rate was 0.803 (Kendall’s coefficient of concordance). In the ×936 zoom group, methylene blue staining was significantly associated with higher accuracy rate (odds ratio 1.76 [1.06–2.92], p value 0.0297). No benefit was observed by double staining. Conclusions: ECS diagnosis with methylene blue provides a high accuracy rate and good interobserver agreement to predict histology of SNADETs.

Diagnostic yield of fourth-generation endocytoscopy for esophageal squamous lesions using a modified endocytoscopic classification.

Endocytoscopy (EC) is an ultra-high magnification endoscopy designed to provide invivo histologic assessment. This study aimed to evaluate the diagnostic yield of the newly developed fourth-generation EC for esophageal squamous lesions by using a modified EC classification. A total of 2548 EC images of 57 esophageal targeted areas between June 2015 and October 2017 were retrospectively collected. Two lesions with low-quality images were excluded. Only EC images were independently reviewed by two expert and two non-expert endoscopists. The lesions were classified according to a three-tier modified EC classification. We used a multilevel logistic regression to analyze the data. The sensitivity and specificity of diagnosing non-squamous cell cancer (SCC) vs SCC were 82.5% and 83.0% by the experts; 90.1% and 75.0% by non-experts. The interobserver agreement among the four raters was good (kappa statistic 0.59). The diagnostic accuracy of experts and non-experts was similar (P=0.16 for specificity and P=0.20 for sensitivity). The sensitivity and specificity of EC for non-neoplasia vs neoplasia were 88.7% and 74.6% by experts; 90.3 and 52.1% by non-experts. The interobserver agreement among the four raters was moderate (kappa statistic 0.44). The specificity of experts was higher compared to non-experts, although the difference did not reach statistical significance (P=0.08 for specificity and P=0.93 for sensitivity). Fourth-generation EC offers acceptable diagnostic accuracy and reliability in both experts and non-experts, especially when diagnosing SCC lesions.

Robust endocytoscopic image classification based on higher-order symmetric tensor analysis and multi-scale topological statistics.

An endocytoscope is a new type of endoscope that enables users to perform conventional endoscopic observation and ultramagnified observation at the cell level. Although endocytoscopy is expected to improve the cost-effectiveness of colonoscopy, endocytoscopic image diagnosis requires much knowledge and high-level experience for physicians. To circumvent this difficulty, we developed a robust endocytoscopic (EC) image classification method for the construction of a computer-aided diagnosis (CAD) system, since real-time CAD can resolve accuracy issues and reduce interobserver variability. We propose a novel feature extraction method by introducing higher-order symmetric tensor analysis to the computation of multi-scale topological statistics on an image, and we integrate this feature extraction with EC image classification. We experimentally evaluate the classification accuracy of our proposed method by comparing it with three deep learning methods. We conducted this comparison by using our large-scale multi-hospital dataset of about 55,000 images of over 3800 patients. Our proposed method achieved an average 90% classification accuracy for all the images in four hospitals even though the best deep learning method achieved 95% classification accuracy for images in only one hospital. In the case with a rejection option, the proposed method achieved expert-level accurate classification. These results demonstrate the robustness of our proposed method against pit pattern variations, including differences of colours, contrasts, shapes, and hospitals. We developed a robust EC image classification method with novel feature extraction. This method is useful for the construction of a practical CAD system, since it has sufficient generalisation ability.

Mo1635 CLASSIFICATION OF NUCLEAR MORPHOLOGY OF EC FINDINGS IN COLORECTAL ENDOCYTOSCOPY

Endocytoscopy (EC) is a next-generation endoscopy that allows diagnostic imaging at 520× magnification. In the EC classifications, lesions diagnosed as EC3a vary extensively from adenoma to carcinomas with massive submucosal invasion (SM-m), including some lesions that are unsuitable for endoscopic treatment. Therefore, to improve the accuracy of assessing the depth of invasion based on the EC classification, we investigated the presence or absence of 2 factors; high degree of nuclear enlargement (HNE) and multilayered nuclei (MNs), that are indicators of SM-m. Between May 2005 and August 2018, we retrospectively examined 866 lesions diagnosed as EC2 or EC3, according to the EC classification. We subclassified EC 3a into 2 grades (low or high grade) and defined low grade as not recognizing both HNE and MNs, and high grade as for any of the two factors. We examined the diagnostic accuracy of SM-m based on this EC3a subclassification. In addition, we compared the diagnostic ability of EC for SM-m with that of other modalities; narrow-band imaging (NBI) and pit pattern. The sensitivity, specificity, positive predictive value (PPV), negative predictive value NPV), accuracy, and positive likelihood ratio for the diagnostic accuracy of the EC3a subclassification were 89.3%, 91.2%, 80.6%, 92.3%, 90.6%, and 10.1, respectively (P < 0.001). Diagnostic performance for predicting SM-m or worse among EC, NBI and pit pattern is as follows: The sensitivity, specificity, PPV, NPV, and accuracy about EC were 95.1%, 96.5%, 94.9%, 96.7%, 96.0% respectively. On the other hand, those of NBI were 65.0%, 98.7%, 97.0%, 80.7%, 85.1%, and pit pattern were 88.8%, 96.0%, 93.7%, 92.7%, 93.1%, respectively. The sensitivity, specificity, NPV, and accuracy of EC were significantly higher than those of NBI .(P < 0.05) . Futhermore, the sensitivity, NPV, and accuracy of EC were significantly higher than those of pit pattern. (P < 0.05) From the EC findings, the presence of HNE, and MNs are important risk factors for SM-m or worse outcomes. Furthermore, the EC3a subclassification taking account of these findings could be effective for the diagnosis of SM-m or worse.

Endocytoscopy: technology and clinical application in upper gastrointestinal tract.

Over the past few years, the innovative field of magnifying endoscopy has been expanding with various cutting-edge technologies, one of which is endocytoscopy, to facilitate improvement in the detection and diagnosis of gastrointestinal lesions. Endocytoscopy is a novel ultra-high magnification endoscopic technique enabling high-quality in-vivo assessment of lesions found in the gastrointestinal tract with the use of intraprocedural stains. The main scope of this review article is to offer a closer look at the latest endocytoscopic technology and its clinical application in the upper gastrointestinal tract, especially in the esophagus and stomach, as well as to introduce readers to our simplified and up-to-date endocytoscopic classification, specifically developed for the esophagus and stomach, for the in-vivo assessment and diagnosis of esophageal and gastric lesions. Despite the good accuracy of endocytoscopy in the diagnosis of esophageal and gastric lesions in recent studies, some challenges still remain (e.g., staining method and standardized endocytoscopic classification). Through continuous evaluation and improvement of methods and skills, these challenges may be overcome thus establishing current techniques and classification, paving the way for further advances in the field of endocytoscopy and magnifying endoscopy. In all, endocytoscopy seems to aid in the in-vivo diagnosis of gastrointestinal tract lesions and may, in the future, revolutionize the field of in-vivo endoscopic diagnosis of gastrointestinal cancer, representing another step towards the so-called optical biopsy.

Sa1909 GRADING OF DYSPLASIA FOR DIAGNOSING COLORECTAL ADENOMAS USING ENDOCYTOSCOPY

Recent opinions have expressed that if an endoscopic diagnosis of adenomas can be made with high accuracy, then, the omission of a pathological diagnosis following endoscopic resection is acceptable. Currently, there is no clear consensus regarding whether endoscopic treatment is required for all adenomas. Colonoscopy-based grading of dysplasia can be clinically effective for diagnosing adenomas, if such a diagnosis of adenomas, particularly of low-grade adenomas, can be made with high accuracy. In this study, we focused on the existence of mixed-pit pattern type I lesions in slit-like lumens, which is an endocytoscopy (EC) finding characteristic of adenomas, and investigated pathological findings that were correlated with this observation. We retrospectively examined 724 lesions among the neoplastic lesions that could be observed by EC between May 2005 and May 2017 and that were classified as EC2 according to the EC classification system and could be pathologically examined via endoscopic resection. Lesions characterized by mixed-pit pattern type I in slit-like lumens were classified as EC2 normal pit (NP) sign (+), while those characterized by slit-like lumens only were classified as EC2 NP sign (−). We investigated the final pathological diagnosis results, and also examined the location, diameter, and morphological type of NP (+) lesions to elucidate their clinical traits. A total of 466 lesions were classified as EC2 NP sign (+). Of these, low-grade adenomas accounted for 450 lesions and advanced lesions (high-grade dysplasia, tubulovillous adenoma, invasive cancer) accounted for 16. NP sign (+) as an indicator of low-grade adenomas had a sensitivity of 85.4%, specificity of 90.8%, positive predictive value of 96.6%, negative predictive value of 67.1%, accuracy of 86.7%, and positive likelihood ratio of 9.23. Furthermore, an examination of the EC2 NP (+) rate by location, diameter, and morphological type of the lesions revealed that 56.6% of the lesions were located in the distal colon and 75.7% were located in the proximal colon; 81.4% of the lesions were ≤10 mm in diameter and 10.9% were ≥10 mm. Further, 53.9% of the lesions were of the protruding morphological type and 79.8% were of the flat/depressed type. Taken together, this indicated that the EC2 NP sign (+) rate was significantly higher in lesions located in the proximal colon (p < 0.001), that were ≤10 mm in diameter (p < 0.001), and that were of the flat/depressed type (p < 0.001). These results suggest that when using EC for diagnosing colorectal neoplastic lesions, NP sign is a good indicator of low-grade adenomas with the EC2 classification. Furthermore, the NP (+) rate tended to be high in lesions located in the proximal colon, that were ≤10 mm in diameter, and that were of the flat/depressed type.

P029 ENDOCYTOSCOPIC FINDINGS PREDICT RELAPSE IN PATIENTS WITH ULCERATIVE COLITIS DURING LONG-TERM FOLLOW-UP NO LESS THAN 5 YEARS

This study was conducted to explore the association of endocytoscopy (EC) findings with inflammatory activity and clinical course in ulcerative colitis (UC). EC was conducted for mild to moderate UC 32 cases from January 2010 to August 2016. The EC findings were classified into 4 types: EC-A, regular arrangement of round to oval pits; EC-B, irregular arrangement with/without enlarged spaces between regular pits; EC-C, irregular pits in size and shape with more irregular arrangement of pits; and EC-D, disruptive or disappeared pits. The association of EC classification with Mayo endoscopic grades and clinical activity was examined. A experienced pathologist who was blinded to clinical and endoscopic information evaluated the slices for histopathological assessment of inflammation in UC with special reference to the severity in mucosal inflammatory infiltrates and the presence of crypt abscess and goblet cell depletion. The UC patients who underwent EC were followed up more than 60 months in 22 cases. As a result, there were 15 cases in EC-A, 8 in EC-B, 5 in EC-C and 4 in EC-D. The interobserver agreement was excellent. Each EC-A case was in clinically remission stage, while all the EC-C and EC-D cases were in active stage. In the EC-B group, there were each 4 cases in remission and active stage, respectively. The EC-A cases were divided into Mayo 0 (n=11) and Mayo 1 (n=4), while the EC-B cases were into Mayo 0 (n=2) and Mayo 1 (n=6). There were no cases of Mayo 0 grade in the EC-C and -D group. The EC stratification was significantly associated with the pathognomonic microscopic features. There were significant differences in the percentages of the remission among the EC classifications. None had relapse in the EC-A group during the follow-up period. EC classification could be predictive for relapse in ulcerative colitis. In addition, EC is reliable for assessment of the microscopic inflammatory features.

In vivo detection of desmoplastic reaction using endocytoscopy: A new diagnostic marker of submucosal or more extensive invasion in colorectal carcinoma.

The pathological determination of desmoplastic reaction (DR) in colorectal carcinoma is useful for predicting extensive submucosal invasion. The aim of the present study was to determine the usefulness of endocytoscopy (EC) in detecting DR. A total of 72 cases of colorectal cancer with submucosal invasion (EC classification, EC3b) were evaluated. The utility of fine granular structure (FGS) observed via EC for the prediction of the presence of DR in the most superficial tumor layers was assessed. Of the 72 lesions, 26 were positive for FGS, and the majority of these lesions (23/26, 88.5%) exhibited a DR, indicating a significant association. The overall accuracy of the identification of FGS via EC that was predictive of a DR was 87.3%. The presence of FGS detected by EC was significantly associated with the presence of a DR, suggesting the clinical usefulness of EC in planning treatment for colon cancer with submucosal invasion.

Classification of nuclear morphology in endocytoscopy of colorectal neoplasms

We investigated endocytoscopy (EC) findings that were considered risk factors for colorectal neoplasms and determined whether they could be used as new indices to identify carcinomas with massive submucosal invasion (SM-m) or worse outcomes. We performed a multivariate analysis of 8 factors on EC images to determine whether they were associated with SM-m or worse. Based on the results, we divided the EC3a category of the EC classification into low grade or high grade and investigated the diagnostic accuracy of this subclassification. In addition, we compared the diagnostic ability of EC for SM-m with that of other modalities (narrow-band imaging and pit pattern). The multivariate analysis indicated that unclear glandular lumens (ULs), high degree of nuclear enlargement (HNE), and multilayered nuclei (MNs) were the most useful factors for the diagnosis of SM-m or worse. The odds ratios for these factors were 12.47, 12.29, and 10.48, respectively (P< .001). The sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and positive likelihood ratio for the diagnostic accuracy of the EC3a subclassification were 88.9%, 91.3%, 75.0%, 96.6%, 90.8%, and 10.2, respectively (P< .001). The sensitivity, negative predictive value, and accuracy of EC were significantly higher than those of narrow-band imaging and pit pattern. From the EC findings, the presence of ULs, HNE, and MNs are important risk factors for SM-m orworse outcomes. Furthermore, the EC3a subclassification taking these findings into consideration could be effective for the diagnosis of SM-m or worse. (Clinical trial registration number: UMIN 000014906.).

Su1615 Diagnostic Characteristics of Depressed Type Colorectal Neoplasms in Magnifying Endoscopy and Endocytoscopy

Colorectal cancers are generally recognized to develop from“polyps”. This “adenoma-carcinoma sequence” theory has been in the mainstream of development of colorectal cancers. But recently the existence of many depressed-type cancers has been revealed, which are considered to emerge directly from normal epithelium, not through the adenomatous stage. This theory is called “de novo” pathway. Now, it is possible to presume the histology of colorectal lesions using magnifying endoscopy(pit pattern classification) and endocytoscopy(EC).We can observe not only the structural atypia but also the cellular atypia in living colorectal lesions. The aim is to clarify the diagnostic characteristics of depressed-type colorectal neoplasms, demonstrating the validity of pit pattern diagnosis and EC classification.

Endocytoscopic microvasculature evaluation is a reliable new diagnostic method for colorectal lesions (with video)

We previously reported on the efficacy of endocytoscopic classification (EC-C). However, the correlation of the endocytoscopic vascular (EC-V) pattern with diagnoses was unclear. To assess the diagnostic accuracy of the EC-V pattern for colorectal lesions. Retrospective. A university hospital. Patients who underwent endocytoscopy between January 2010 and March2013. We evaluated 198 consecutive lesions according to the EC-V pattern (EC-V1, obscure surface microvessels; EC-V2, clearly observed surface microvessels of a uniform caliber and arrangement; and EC-V3, dilated surface microvessels of a nonhomogeneous caliber or arrangement). The diagnostic accuracy for predicting hyperplastic polyps and invasive cancer were compared between the EC-V pattern and other modalities (narrow-band imaging, pit pattern, and EC-C). The sensitivity, specificity, and accuracy of the EC-V1 pattern for diagnosing hyperplastic polyps were 95.5%, 99.4%, and 99.0%, respectively. The sensitivity, specificity, and accuracy of the EC-V3 pattern for diagnosing invasive cancer were 74.6%, 97.2%, and 88.6%, respectively. The diagnostic accuracy of the EC-V pattern for predicting hyperplastic polyps was comparable to the other modalities. For predicting invasive cancer, the EC-V pattern was comparable to narrow-band imaging and pit pattern, although EC-C was slightly more accurate (P= .04). In the substudy, the diagnosis time by using the EC-V pattern was shorter than that with the EC-C pattern (P< .001). A single-center, retrospective study. The EC-V pattern saved more time than the EC-C pattern and had a diagnostic ability comparable to that of other optical biopsy modalities.

Su1702 Diagnostic Characteristics of Depressed Type Colorectal Neoplasms Examined With Magnifying Chromo-Endoscopy and Endocytoscopy

Su1702 Diagnostic Characteristics of Depressed Type Colorectal Neoplasms Examined With Magnifying Chromo-Endoscopy and Endocytoscopy Shin-Ei Kudo*, Kazuki Kato, Katsuro Ichimasa, Hideyuki Miyachi, Yuta Kouyama, Shingo Matsudaira, Hiromasa Oikawa, Tomokazu Hisayuki, Yui J. Kimura, Yuichi Mori, Masashi Misawa, Toyoki Kudo, Kenta Kodama, Kunihiko Wakamura, Takemasa Hayashi, Atsushi Katagiri, Eiji Hidaka, Fumio Ishida Showa University Northern Yokohama Hospital, Yokohama, Japan Introduction & Aim: Colorectal carcinomas are generally recognized to develop from sessile-type “polyps”. This “adenoma-carcinoma sequence” theory has been in the mainstream of development of colorectal cancers. But recently the existence of many depressed-type cancers has been revealed, which are considered to emerge directly from normal epithelium, not through the adenomatous stage. This theory is called “de novo” pathway. Now, it is possible to estimate the histology of colorectal lesions using magnifying chromo-endoscopy (pit pattern classification) and endocytoscopy (EC) which can observe not only the structural atypia but also the cellular atypia in living colorectal lesions. The aim is to clarify the diagnostic characteristics of depressed-type colorectal neoplasms, demonstrating the validity of pit pattern diagnosis and EC classification. Methods: A total of 22903 colorectal neoplasms excluding advanced carcinomas were resected endoscopically or surgically in our unit from April 2001 to June 2014. Of these, 14522 lesions were low-grade dysplasia, 4956 were high-grade dysplasia and 968 were submucosally invasive (T1) carcinomas. According to morphological/development classification, they were divided into 3 types: depressed, flat and sessile type. We investigated the rate of T1 carcinomas and the characteristics of depressed-type neoplasms concerning pit pattern and EC classification. Results: The rate of T1 carcinomas in depressed-type lesions reached to 63.7 %, meanwhile that in flat-type and sessile-type lesions was 4.1 % and 3.1 %, respectively. Within less than 5mm in diameter, that was 10.2 %, 0 % and 0.06 %, respectively. Most (88.3 % and 91.2 %) of the flat-type and sessile-type lesions showed type IIIL or IV pit pattern corresponding to adenomas, whereas 94.5 % of the depressed-type lesions were characterized by type IIIs, VI or VN pit pattern corresponding to carcinomas. As for endocytoscopy, most of the flatand sessile-type lesions showed EC2 corresponding to adenomas. In contrast, the depressed-type lesions were observed as EC3a (23.5 %) and EC3b (74.1 %) corresponding to invasive carcinomas. Conclusion: This study revealed the diagnostic characteristics of depressed-type lesions. They show typically type IIIs, VI or VN pit patterns in magnifying endoscopy and type EC3a or EC3b in endocytoscopy. These lesions tend to invade the submucosal layer even when they are small. Therefore, more careful endoscopic diagnosis of ‘whether the lesion is depressed type or not’ would be important.

Su1703 High Definition Colonoscopy With I-SCAN and Digital Chromoendoscopy in the Pit Pattern Analysis: a Single Center Experience

Su1702 Diagnostic Characteristics of Depressed Type Colorectal Neoplasms Examined With Magnifying Chromo-Endoscopy and Endocytoscopy Shin-Ei Kudo*, Kazuki Kato, Katsuro Ichimasa, Hideyuki Miyachi, Yuta Kouyama, Shingo Matsudaira, Hiromasa Oikawa, Tomokazu Hisayuki, Yui J. Kimura, Yuichi Mori, Masashi Misawa, Toyoki Kudo, Kenta Kodama, Kunihiko Wakamura, Takemasa Hayashi, Atsushi Katagiri, Eiji Hidaka, Fumio Ishida Showa University Northern Yokohama Hospital, Yokohama, Japan Introduction & Aim: Colorectal carcinomas are generally recognized to develop from sessile-type “polyps”. This “adenoma-carcinoma sequence” theory has been in the mainstream of development of colorectal cancers. But recently the existence of many depressed-type cancers has been revealed, which are considered to emerge directly from normal epithelium, not through the adenomatous stage. This theory is called “de novo” pathway. Now, it is possible to estimate the histology of colorectal lesions using magnifying chromo-endoscopy (pit pattern classification) and endocytoscopy (EC) which can observe not only the structural atypia but also the cellular atypia in living colorectal lesions. The aim is to clarify the diagnostic characteristics of depressed-type colorectal neoplasms, demonstrating the validity of pit pattern diagnosis and EC classification. Methods: A total of 22903 colorectal neoplasms excluding advanced carcinomas were resected endoscopically or surgically in our unit from April 2001 to June 2014. Of these, 14522 lesions were low-grade dysplasia, 4956 were high-grade dysplasia and 968 were submucosally invasive (T1) carcinomas. According to morphological/development classification, they were divided into 3 types: depressed, flat and sessile type. We investigated the rate of T1 carcinomas and the characteristics of depressed-type neoplasms concerning pit pattern and EC classification. Results: The rate of T1 carcinomas in depressed-type lesions reached to 63.7 %, meanwhile that in flat-type and sessile-type lesions was 4.1 % and 3.1 %, respectively. Within less than 5mm in diameter, that was 10.2 %, 0 % and 0.06 %, respectively. Most (88.3 % and 91.2 %) of the flat-type and sessile-type lesions showed type IIIL or IV pit pattern corresponding to adenomas, whereas 94.5 % of the depressed-type lesions were characterized by type IIIs, VI or VN pit pattern corresponding to carcinomas. As for endocytoscopy, most of the flatand sessile-type lesions showed EC2 corresponding to adenomas. In contrast, the depressed-type lesions were observed as EC3a (23.5 %) and EC3b (74.1 %) corresponding to invasive carcinomas. Conclusion: This study revealed the diagnostic characteristics of depressed-type lesions. They show typically type IIIs, VI or VN pit patterns in magnifying endoscopy and type EC3a or EC3b in endocytoscopy. These lesions tend to invade the submucosal layer even when they are small. Therefore, more careful endoscopic diagnosis of ‘whether the lesion is depressed type or not’ would be important.

Su1701 Interobserver Agreement and Accuracy of Probe Based Endocytoscopy (PEC) in Predicting Colorectal Neoplasia Among Endoscopists

Probe based endocytoscopy (pEC) has been reported to allow immediate diagnosis of colorectal lesions based on imaging epithelium in vivo during any ongoing endoscopy using the endocytoscopy classification (ECS) with a reported high accuracy (91% sensitivity and 100% specificity). However, there is no information regarding the interobserver agreement and validation of endocytoscopy image criteria. Furtheremore, there are no reports of pEC in US centers. The aims of our study were to assess the interobserver agreement and accuracy of this novel technology for prediction of colorectal neoplasia using pEC among 3 endoscopists familiar with advanced imaging technologies.

Sa1591 The Diagnostic Ability of Micro Vascular Pattern Observed by Endocytoscopy

Sa1591 The Diagnostic Ability of Micro Vascular Pattern Observed by Endocytoscopy

705 Prophylasix of Post-ERCP Pancreatitis With Nafamostat Mesilate: Comparison of 24-Hour and 8-Hour Infusion of Nafamostat Mesilate: a Prospective Randomized Comparison Trial

705 Prophylasix of Post-ERCP Pancreatitis With Nafamostat Mesilate: Comparison of 24-Hour and 8-Hour Infusion of Nafamostat Mesilate: a Prospective Randomized Comparison Trial

Diagnostic performance of endocytoscopy for evaluating the invasion depth of different morphological types of colorectal tumors.

Endocytoscopy (EC) is a next-generation endoscopic technique that enables diagnostic imaging at 450× magnification. In the present study, we retrospectively evaluated the diagnostic performance of EC and magnifying chromoendoscopy (MCE) for diagnosing the invasion depth of colorectal tumors. We investigated 330 lesions with a ≥10-mm tumor diameter that could be diagnosed by both MCE and EC. The lesions were classified according to morphological type as follows: laterally spreading type-granular (LST-G), laterally spreading type-non-granular (LST-NG), protruding, or depressed. After all lesions had been classified by both pit pattern and EC, qualitative and quantitative (invasion depth) diagnoses were made. The diagnostic accuracy was then compared between pit pattern classification and EC classification. Diagnostic accuracy of EC classification was significantly higher for LST-NG lesions (90.5%) than for protruding lesions (80.6%) (P < 0.05). Diagnostic accuracy for LST-NG lesions was significantly higher with EC classification (90.5%) than with pit pattern classification (79.3%) (P < 0.001). Comparison of the diagnostic performance of EC3a findings using EC classification between LST-NG and protruding lesions revealed a sensitivity of 92.9% versus 11.3% (P < 0.001), positive predictive value of 78.0% versus 27.3% (P < 0.001), negative predictive value of 95.5% versus 56.1% (P < 0.001), and diagnostic accuracy of 87.9% versus 51.2% (P < 0.001), respectively. EC is a very useful method for evaluating the invasion depth of LST-NG lesions.

Diagnostic Technique: In Vivo Diagnosis of Cellular Atypia Using Endocytoscope: EC Classification in Squamous Epithelium

Endocytoscopy enables us to observe cellular nucleus in vivo in the squamous esophagus and pharynx. Endocytoscopy is a contact endoscopy with 340-1100-fold magnification. Topical spray of crystal violet and methylene blue solution creates a well-contrasted image which is similar to hematoxylin and eosin staining. Endocytoscopic findings of tissue atypia are summarized in endocytoscopic (EC) classification. EC-1 is nonneoplastic, which includes normal (EC-1a) and inflammatory or reactive (EC-1b). EC-2 is a borderline lesion. EC-3 is a cancerous image, often with increased cellularity and with enlarged and polymorphic nuclei. This article is part of an expert video encyclopedia.