• Asian Pacific Journal of Cancer Prevention
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• v.17 no.11
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• pp.4869-4873
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• 2016

Colonoscopy is currently the best technique available for the detection of colon cancer or colorectal polyps or other precursor lesions. Computer aided detection (CAD) is based on very complex pattern recognition. Local binary patterns (LBPs) are strong illumination invariant texture primitives. Histograms of binary patterns computed across regions are used to describe textures. Every pixel is contrasted relative to gray levels of neighbourhood pixels. In this study, colorectal polyp detection was performed with colonoscopy video frames, with classification via J48 and Fuzzy. Features such as color, discrete cosine transform (DCT) and LBP were used in confirming the superiority of the proposed method in colorectal polyp detection. The performance was better than with other current methods.

• Clinical Endoscopy
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• v.55 no.1
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• pp.113-121
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• 2022

Background/Aims: We have been developing artificial intelligence based polyp histology prediction (AIPHP) method to classify Narrow Band Imaging (NBI) magnifying colonoscopy images to predict the hyperplastic or neoplastic histology of polyps. Our aim was to analyze the accuracy of AIPHP and narrow-band imaging international colorectal endoscopic (NICE) classification based histology predictions and also to compare the results of the two methods. Methods: We studied 373 colorectal polyp samples taken by polypectomy from 279 patients. The documented NBI still images were analyzed by the AIPHP method and by the NICE classification parallel. The AIPHP software was created by machine learning method. The software measures five geometrical and color features on the endoscopic image. Results: The accuracy of AIPHP was 86.6% (323/373) in total of polyps. We compared the AIPHP accuracy results for diminutive and non-diminutive polyps (82.1% vs. 92.2%; p=0.0032). The accuracy of the hyperplastic histology prediction was significantly better by NICE compared to AIPHP method both in the diminutive polyps (n=207) (95.2% vs. 82.1%) (p<0.001) and also in all evaluated polyps (n=373) (97.1% vs. 86.6%) (p<0.001) Conclusions: Our artificial intelligence based polyp histology prediction software could predict histology with high accuracy only in the large size polyp subgroup.

• Clinical Endoscopy
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• v.55 no.4
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• pp.540-548
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• 2022

Background/Aims: Colorectal polyps are removed to prevent progression to colorectal cancer. Polyp size is an important factor for risk stratification of malignant transformation. Endoscopic size estimation correlates poorly with pathological reports and several factors have been suggested to influence size estimation. We aimed to gain insight into the factors influencing endoscopic polyp size estimation. Methods: Images of polyps in an artificial model were obtained at 1, 3, and 5 cm from the colonoscope's tip. Participants were asked to estimate the diameter and volume of each polyp. Results: Fifteen endoscopists from three large-volume centers participated in this study. With an intraclass correlation coefficient of 0.66 (95% confidence interval [CI], 0.62-0.71) for diameter and 0.56 (95% CI, 0.50-0.62) for volume. Polyp size estimated at 3 cm from the colonoscope's tip yielded the best results. A lower distance between the tip and the polyp was associated with a larger estimated polyp size. Conclusions: Correct endoscopic estimation of polyp size remains challenging. This finding can affect size estimation skills and future training programs for endoscopists.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.97-99
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• 2022

For the early identification and treatment of colorectal cancer, accurate polyp segmentation is crucial. However, polyp segmentation is a challenging task, and the majority of current approaches struggle with two issues. First, the position, size, and shape of each individual polyp varies greatly (intra-class inconsistency). Second, there is a significant degree of similarity between polyps and their surroundings under certain circumstances, such as motion blur and light reflection (inter-class indistinction). U-net, which is composed of convolutional neural networks as encoder and decoder, is considered as a standard for tackling this task. We propose an updated U-net architecture replacing the encoder part with vision transformer network for polyp segmentation. The proposed architecture performed better than the standard U-net architecture for the task of polyp segmentation.

• Clinical Endoscopy
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• v.56 no.4
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• pp.479-489
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• 2023

Background/Aims: Accurate neoplastic prediction can significantly decrease costs associated with pathology and unnecessary colorectal polypectomies. Narrow-band imaging (NBI) and dual-focus (DF) mode are promising emerging optical technologies for recognizing neoplastic features of colorectal polyps digitally. This study aimed to clarify the clinical usefulness of NBI with and without DF assistance in the neoplastic prediction of small colorectal polyps (<10 mm). Methods: This cross-sectional study included 530 small colorectal polyps from 343 consecutive patients who underwent colonoscopy at the University Medical Center from September 2020 to May 2021. Each polyp was endoscopically diagnosed in three successive steps using white-light endoscopy (WLE), NBI, and NBI-DF and retrieved for histopathological assessment. The diagnostic accuracy of each modality was evaluated with reference to histopathology. Results: There were 295 neoplastic polyps and 235 non-neoplastic polyps. The overall accuracies of WLE, WLE+NBI, and WLE+NBI+NBI-DF in the neoplastic prediction of colorectal polyps were 70.8%, 87.4%, and 90.8%, respectively (p<0.001). The accuracy of WLE+NBI+NBI-DF was significantly higher than that of WLE+NBI in the polyp size ≤5 mm subgroup (87.3% vs. 90.1%, p<0.001). Conclusions: NBI improved the real-time neoplastic prediction of small colorectal polyps. The DF mode was especially useful in polyps ≤5 mm in size.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.10
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• pp.4383-4386
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• 2015

Background: The C1561T variant of the glutamate carboxypeptidase II (GCPII) gene is critical for natural methylfolylpolyglutamte (methylfolate) absorption, and has been associated with perturbations in folate metabolism and disease susceptibility. However, little is known on C1561T-GCPII as a risk factor for colorectal cancer. Therefore, this study examined whether C1561T-GCPII influences folate metabolism and adenomatous polyp occurrence. Materials and Methods: 164 controls and 38 adenomatous polyp cases were analysed to determine blood folate and plasma homocysteine (Hcy) level, dietary intake of natural methylfolate, synthetic pteroylglutamic acid (PteGlu), vitamin C and C1561T-GCPII genotype. Results: In controls and cases, 7.3 and 18.4 percent of subjects respectively, were found to have the CT genotype, increasing the risk for adenomatous polyp occurrence 2.86 times (95% CI:1.37-8.0, p=0.035). Total dietary folate, methylfolate and PteGlu intake and the level of erythrocyte folate and plasma Hcy did not predict the occurrence of an adenomatous polyp. However, dietary natural vitamin C intake was associated with adenomatous polyp risk within C1561T-GCPII CT genotype subjects (p=0.037). Conclusions: The findings suggest that C1561T-GCPII variation may be associated with risk for adenomatous polyp, and vitamin C may modify risk by interacting with the variant gene, its expression product and/or folate substrates.

• Journal of Yeungnam Medical Science
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• v.37 no.3
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• pp.246-249
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• 2020

Synchronous gastric cancer and adenomatous colorectal polyp in patients with Klebsiella pneumoniae-induced pyogenic liver abscess (KP-PLA) and bacteremia is a rare presentation. A 58-year-old man with a 6-month history of diabetes mellitus (DM) presented with febrile sensation and dull abdominal pain in the right upper quadrant of the abdomen. Subsequent to laboratory test results and abdominal computed tomography findings, KP-PLA with bacteremia was diagnosed. After intravenous antibiotic administration, his symptoms improved, and upper endoscopy and colonoscopy were performed to evaluate the cause of KP-PLA. Biopsy specimens of the prepyloric anterior wall revealed a moderately differentiated adenocarcinoma. Endoscopic mucosal resection of the colon revealed high-grade dysplasia. Early gastric cancer (EGC) and adenomatous colorectal polyps with high-grade dysplasia concomitant with KP-PLA and bacteremia were diagnosed in our patient who had DM. Intravenous antibiotic treatment for KP-PLA, subtotal gastrectomy for EGC, and colonoscopic mucosal resection for the colon polyp were performed. After 25 days of hospitalization, subtotal gastrectomy with adjacent lymph node dissection was performed. Follow-up ultrasound imaging showed resolution of the abscess 5 weeks post-antibiotic treatment, as well as no tumor metastasis. Upper gastrointestinal endoscopy and colonoscopy should be performed to evaluate gastric cancer in patients with PLA or bacteremia, accompanied with DM or an immunocompromised condition.

• Clinical Endoscopy
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• v.51 no.6
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• pp.534-540
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• 2018

From dye-assisted conventional chromoendoscopy to novel virtual chromoendoscopy, image-enhanced endoscopy (IEE) is continuously evolving to meet clinical needs and improve the quality of colonoscopy. Dye-assisted chromoendoscopy using indigo carmine or crystal violet, although slightly old-fashioned, is still useful to emphasize the pit patterns of the colonic mucosa and predict the histological structures of relevant lesions. Equipment-based virtual chromoendoscopy has the advantage of being relatively easy to use. There are several types of virtual chromoendoscopy that vary depending on the manufacturer and operating principle. IEE plays distinctive roles with respect to histologic characterization of colorectal polyps and prediction of the invasion depth of colorectal cancers. In addition, the newest models of IEE have the potential to increase adenoma and polyp detection rates in screening colonoscopy.

• Clinical Endoscopy
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• v.55 no.5
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• pp.699-700
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• 2022

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9649-9654
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• 2014

Background: Polyps are common lesions in the gastrointestinal (GI) tract. Colon cancer is mostly a result of progression from polyps. The present study aimed to evaluate demographic, clinical, and histological characteristics of colorectal polyps in Iran, particularly neoplastic and advanced types. Materials and Methods: Over a period of 10 years, specimens of all colorectal polyps obtained from colonoscopy were studied. The variables subjected to statistical analysis were age, sex, and the chief clinical complaint of the patients who underwent colonoscopy, their motivation, and the site, size, and histological types of detected polyps. The level of significance was set at p value <0.05. Results: Data were obtained from a total of 352 patients. No difference was seen between male and female patients regarding histological types. Only in nine patients was screening the reason for colonoscopy. Almost two-thirds (66.2%) of the polyps were neoplastic. Familial polyposis syndrome and inflammatory bowel disease were seen in 4.3% and 3.0% of the patients with neoplastic polyps, respectively. Sites of polyps were the sigmoid, rectum, and descending colon in 40.1%, 34.5%, and 17% of the cases, respectively. The advanced type made up 58.8% of neoplastic polyps. Only 3.6% of the patients undergoing colonoscopy in the study period had biopsied polyps. Discussion: No difference was observed between male and female patients in terms of overall incidence of polyps, histological and anatomical profiles, and mean age distribution. Anatomical and histological profiles agreed with the studies performed in areas with a low risk of colon cancer. The findings show that colonoscopy was not performed when it was necessary. A meaningful increase in the number polyp biopsy cases and a corresponding decrease in polyp size in the last few years of the study can be associated with the presence of more GI specialist clinicians in hospital centers, and this holds out much hope for the further improvement of the situation in the future.