Colonoscopy is a reliable diagnostic method to detect colorectal polyps early on and prevent colorectal cancer. The current examination techniques face a significant challenge of high missed rates, resulting in numerous undetected polyps and irregularities. Automated and real-time segmentation methods can help endoscopists to segment the shape and location of polyps from colonoscopy images in order to facilitate clinician's timely diagnosis and interventions. Different parameters like shapes, small sizes of polyps, and their close resemblance to surrounding tissues make this task challenging. Furthermore, high-definition image quality and reliance on the operator make real-time and accurate endoscopic image segmentation more challenging. Deep learning models utilized for segmenting polyps, designed to capture diverse patterns, are becoming progressively complex. This complexity poses challenges for real-time medical operations. In clinical settings, utilizing automated methods requires the development of accurate, lightweight models with minimal latency, ensuring seamless integration with endoscopic hardware devices. To address these challenges, in this study a novel lightweight and more generalized Enhanced Nanonet model, an improved version of Nanonet using NanonetB for real-time and precise colonoscopy image segmentation, is proposed. The proposed model enhances the performance of Nanonet using Nanonet B on the overall prediction scheme by applying data augmentation, Conditional Random Field (CRF), and Test-Time Augmentation (TTA). Six publicly available datasets are utilized to perform thorough evaluations, assess generalizability, and validate the improvements: Kvasir-SEG, Endotect Challenge 2020, Kvasir-instrument, CVC-ClinicDB, CVC-ColonDB, and CVC-300. Through extensive experimentation, using the Kvasir-SEG dataset, our model achieves a mIoU score of 0.8188 and a Dice coefficient of 0.8060 with only 132,049 parameters and employing minimal computational resources. A thorough cross-dataset evaluation was performed to assess the generalization capability of the proposed Enhanced Nanonet model across various publicly available polyp datasets for potential real-world applications. The result of this study shows that using CRF (Conditional Random Fields) and TTA (Test-Time Augmentation) enhances performance within the same dataset and also across diverse datasets with a model size of just 132,049 parameters. Also, the proposed method indicates improved results in detecting smaller and sessile polyps (flats) that are significant contributors to the high miss rates.

• Klíčová slova
• colonoscopy, colorectal cancer, conditional random field, lightweight deep learning models, polyp segmentation, test-time augmentation,
• Publikační typ
• časopisecké články MeSH

Purpose. The purpose of this study was to evaluate the technical and diagnostic performance of sub-milliSievert ultralow-dose (ULD) CT colonograpy (CTC) in the detection of colonic and extracolonic lesions. Materials and Methods. CTC with standard dose (SD) and ULD acquisitions of 64 matched patients, half of them with colonic findings, were reconstructed with filtered back projection (FBP), hybrid (HIR) and iterative model reconstruction techniques (IMR). Image noise in six colonic segments, in the left psoas muscle and aorta were measured. Image quality of the left adrenal gland and of the colon in the endoscopic and 2D view was rated on a five point Likert scale by two observers, who also completed the reading of CTC for colonic and extracolonic findings. Results. The mean radiation dose estimate was 4.1 ± 1.4 mSv for SD and 0.86 ± 0.17 mSv for ULD for both positions (p < 0.0001). In ULD-IMR, SD-IMR and SD-HIR, the endoluminal noise was decreased in all colonic segments compared to SD-FBP (p < 0.001). There were 27 small (6-9 mm) and 17 large (≥10 mm) colonic lesions that were classified as sessile polyps (n = 38), flat lesions (n = 3), or as a mass (n = 3). Per patient sensitivity and specificity were 0.82 and 0.93 for ULD-FBP, 0.97 and 0.97 for ULD-HIR, 0.97 and 1.0 for ULD-IMR. Per polyp sensitivity was 0.84 for ULD-FBP, 0.98 for ULD-HIR, 0.98 for ULD-IMR. Significantly less extracolonic findings were detected in ULD-FBP and ULD-HIR, but in the E4 category by C-RADS (potentially important findings), the detection was similar. Conclusion. Both HIR and IMR are suitable for sub-milliSievert ULD CTC without sacrificing diagnostic performance of the study.

• Klíčová slova
• CT colonography, Iterative reconstruction technique, Low-dose, Polyp,
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Computed tomography (CT) colonography is a well established modality for the examination of symptomatic patients as well as in screening. Recent technical advances in improving image quality by iterative reconstruction contribute to the reduction of the radiation dose which is a major concern in CT imaging. PURPOSE: To evaluate image quality of ultralow-dose submilisievert CT colonography using hybrid iterative reconstruction technique. MATERIAL AND METHODS: Sixteen patients underwent contrast-enhanced CT colonography with standard protocol in supine position and ultralow-dose protocol in prone position. Ultralow-dose datasets were reconstructed with filtered back projection and an advanced hybrid iterative reconstruction technique. Two radiologists independently evaluated 96 colonic segments for image quality in the endoluminal view and axial thin sections. Colonic distension, smoothness of colonic wall and distortion of folds in the endoluminal view, sharpness of colonic wall delineation, perceived image noise, and presence of photon starvation artifact were rated on a five-point scale. Intraluminal noise expressed as standard deviation of Hounsfield density was measured in all segments. RESULTS: The mean radiation dose was 0.42 mSv and 5.48 mSv in prone and supine scans, respectively. All distended segments were rated evaluable in standard dose and ultralow-dose series reconstructed with the iterative reconstruction technique, whereas in 61% segments image quality was rated poor or unacceptable in ultralow-dose series where filtered back projection was used with worst ratings in the rectum and the sigmoid colon. CONCLUSION: This pilot study shows that iterative reconstruction technique is a feasible method to decrease the radiation dose from CT colonography for both positions below 1mSv. Further investigations of larger scale need to be done to clarify, whether such a low radiation dose would influence the detection of polyps.

• Klíčová slova
• Colonography, colon, computed tomography, iterative reconstruction, low-dose, polyp,
• MeSH
• dávka záření * MeSH
• kolonografie počítačovou tomografií metody   MeSH
• kontrastní látky MeSH
• kyseliny trijodbenzoové MeSH
• lidé MeSH
• nemoci střev diagnostické zobrazování   MeSH
• pilotní projekty MeSH
• rentgenový obraz - interpretace počítačová metody   MeSH
• senioři MeSH
• studie proveditelnosti MeSH
• vylepšení rentgenového snímku metody   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ioversol MeSH Prohlížeč
• kontrastní látky MeSH
• kyseliny trijodbenzoové MeSH

Wireless capsule endoscopy (WCE) is one of the most efficient methods for the examination of gastrointestinal tracts. Computer-aided intelligent diagnostic tools alleviate the challenges faced during manual inspection of long WCE videos. Several approaches have been proposed in the literature for the automatic detection and localization of anomalies in WCE images. Some of them focus on specific anomalies such as bleeding, polyp, lesion, etc. However, relatively fewer generic methods have been proposed to detect all those common anomalies simultaneously. In this paper, a deep convolutional neural network (CNN) based model 'WCENet' is proposed for anomaly detection and localization in WCE images. The model works in two phases. In the first phase, a simple and efficient attention-based CNN classifies an image into one of the four categories: polyp, vascular, inflammatory, or normal. If the image is classified in one of the abnormal categories, it is processed in the second phase for the anomaly localization. Fusion of Grad-CAM++ and a custom SegNet is used for anomalous region segmentation in the abnormal image. WCENet classifier attains accuracy and area under receiver operating characteristic of 98% and 99%. The WCENet segmentation model obtains a frequency weighted intersection over union of 81%, and an average dice score of 56% on the KID dataset. WCENet outperforms nine different state-of-the-art conventional machine learning and deep learning models on the KID dataset. The proposed model demonstrates potential for clinical applications.

• Klíčová slova
• Anomaly detection, Attention mechanism, Deep convolutional neural network, Localization, Wireless capsule endoscopy,
• MeSH
• algoritmy MeSH
• kapslová endoskopie * MeSH
• neuronové sítě MeSH
• počítačové zpracování obrazu MeSH
• ROC křivka MeSH
• strojové učení MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

We studied three patients in whom histology revealed multiple lymphomatous polyposis of the gastrointestinal tract. It is a distinctive type of primary gastrointestinal lymphoma characterized by polypoid accumulations of lymphoma tissue involving long segments of the gastrointestinal tract. This lymphoma consists of a diffuse proliferation of small round lymphocytes and small cleaved cells and tends to an extraintestinal dissemination. Clinical behavior of this entity is more aggressive than that of the same primary nodal lymphoma. We discuss the evolution of opinions of this entity.

• MeSH
• gastrointestinální nádory patologie   MeSH
• lidé MeSH
• lymfom patologie   MeSH
• polypy patologie   MeSH
• senioři MeSH
• Check Tag
• lidé MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• kazuistiky MeSH

Evaluation of the dysplastic changes evolving in mucosa of various segments of gastrointestinal tract is a part of routine practice. Morphologically different or non-conventional types of dysplastic changes are described in the mucosa of gastrointestinal tract besides the most common conventional type of dysplasia. Non-conventional dysplasias can arise de-novo or they can be found in association with chronic gastrointestinal conditions, such as Barretts esophagus, chronic atrophic gastritis, and inflammatory bowel disease. Non-conventional types of dysplasia include serrated, crypt base of foveolar dysplasia and lesions as pyloric or oxyntic gland adenoma. Non-conventional types of dysplasia arising in inflammatory bowel disease represent specific category with broad morphological spectrum of changes. The aim of this work is to present a comprehensive review of morphological characteristics of individual subtypes of non-conventional dysplastic changes with focus on differences and specificity in particular parts of gastrointestinal tract and provide a functional handout for daily diagnostic practice.

• Klíčová slova
• Dysplasia, IBD-associated dysplasia, foveolar dysplasia, intraepithelial neoplasia, non-conventional type, serrated dysplasia,
• MeSH
• adenomové polypy * komplikace   patologie   MeSH
• hyperplazie patologie   MeSH
• idiopatické střevní záněty * komplikace   diagnóza   patologie   MeSH
• kolorektální nádory * patologie   MeSH
• lidé MeSH
• prekancerózy * komplikace   patologie   MeSH
• sliznice patologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

BACKGROUND AND AIMS: Adequate bowel preparation is essential for successful and effective colonoscopy. Several types of cleansing agents are currently available including low-volume solutions. The aim of this study was to compare the efficacy of four different bowel cleansing agents. METHODS: A single-center, prospective, randomized, and single-blind study was performed. Consecutive patients referred for colonoscopy were enrolled and randomized into one of the following types of laxatives: polyethylenglycol 4L (PEG), oral sulfate solution (OSS), 2L polyethylenglycol + ascorbate (2L-PEG/Asc), or magnesium citrate + sodium picosulfate (MCSP). The primary outcome was quality of bowel cleansing evaluated according to the Boston Bowel Preparation Scale (BBPS). Secondary outcomes were polyp detection rate (PDR) and tolerability. RESULTS: Final analysis was performed on 431 patients. The number of patients with adequate bowel preparation (BBPS total scores ≥6 and sub scores ≥2 in each segment) was not significantly different throughout all groups (95.4% PEG; 94.6% OSS; 96.3% 2L-PEG/Asc; 96.2% MCSP; p=0.955). Excellent bowel preparation (BBPS total scores ≥ 8) was associated with younger age (p=0.007). The groups did not have significantly different PDRs (49.5% PEG; 49.1% OSS; 38% 2L-PEG/Asc; 40.4% MCSP; p=0.201). The strongest predictors of pathology identification were age and male gender. The best-tolerated solution was MCSP (palatability: p<0.001; nausea: p=0.024).

• MeSH
• detergenty * MeSH
• jednoduchá slepá metoda MeSH
• kolonoskopie MeSH
• lidé MeSH
• polyethylenglykoly škodlivé účinky   MeSH
• prospektivní studie MeSH
• purgativa * škodlivé účinky   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie MeSH
• Názvy látek
• detergenty * MeSH
• polyethylenglykoly MeSH
• purgativa * MeSH

The author presents a selective review on the gene contents of the second human chromosome, in particular with regard to pathogenesis. Among the best known ones the author mentions genes the alleles of which cause anomalies of apolipoprotein B, disorders of blood clotting caused by defects of C protein and Waardenburg's syndrome associated with disorders of the function of one of the regulating genes of the PAX family. Variable and constant gene segments of the immunoglobulin chain kappa, incl. pseudogenes, can be considered dominating. A new sphere of research interest developed in conjunction with the finding of a gene conditioning familial non-polypous carcinoma of the large intestine.

• MeSH
• lékařská genetika MeSH
• lidé MeSH
• lidské chromozomy, pár 2 * MeSH
• mapování chromozomů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH

1: ESGE suggests performing segmental biopsies (at least two from each segment), which should be placed in different specimen containers (ileum, cecum, ascending, transverse, descending, and sigmoid colon, and rectum) in patients with clinical and endoscopic signs of colitis.Weak recommendation, low quality of evidence. 2: ESGE recommends taking two biopsies from the right hemicolon (ascending and transverse colon) and, in a separate container, two biopsies from the left hemicolon (descending and sigmoid colon) when microscopic colitis is suspected.Strong recommendation, low quality of evidence. 3: ESGE recommends pancolonic dye-based chromoendoscopy or virtual chromoendoscopy with targeted biopsies of any visible lesions during surveillance endoscopy in patients with inflammatory bowel disease. Strong recommendation, moderate quality of evidence. 4: ESGE suggests that, in high risk patients with a history of colonic neoplasia, tubular-appearing colon, strictures, ongoing therapy-refractory inflammation, or primary sclerosing cholangitis, chromoendoscopy with targeted biopsies can be combined with four-quadrant non-targeted biopsies every 10 cm along the colon. Weak recommendation, low quality of evidence. 5: ESGE recommends that, if pouch surveillance for dysplasia is performed, visible abnormalities should be biopsied, with at least two biopsies systematically taken from each of the afferent ileal loop, the efferent blind loop, the pouch, and the anorectal cuff.Strong recommendation, low quality of evidence. 6: ESGE recommends that, in patients with known ulcerative colitis and endoscopic signs of inflammation, at least two biopsies be obtained from the worst affected areas for the assessment of activity or the presence of cytomegalovirus; for those with no evident endoscopic signs of inflammation, advanced imaging technologies may be useful in identifying areas for targeted biopsies to assess histologic remission if this would have therapeutic consequences. Strong recommendation, low quality of evidence. 7: ESGE suggests not biopsying endoscopically visible inflammation or normal-appearing mucosa to assess disease activity in known Crohn's disease.Weak recommendation, low quality of evidence. 8: ESGE recommends that adequately assessed colorectal polyps that are judged to be premalignant should be fully excised rather than biopsied.Strong recommendation, low quality of evidence. 9: ESGE recommends that, where endoscopically feasible, potentially malignant colorectal polyps should be excised en bloc rather than being biopsied. If the endoscopist cannot confidently perform en bloc excision at that time, careful representative images (rather than biopsies) should be taken of the potential focus of cancer, and the patient should be rescheduled or referred to an expert center.Strong recommendation, low quality of evidence. 10: ESGE recommends that, in malignant lesions not amenable to endoscopic excision owing to deep invasion, six carefully targeted biopsies should be taken from the potential focus of cancer.Strong recommendation, low quality of evidence.

• MeSH
• gastrointestinální endoskopie * MeSH
• kolon diagnostické zobrazování   MeSH
• lidé MeSH
• prekancerózy * MeSH
• rektum diagnostické zobrazování   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Oral sodium phosphate (NaP) has been increasingly used for bowel preparation before the colonoscopy because it shows good patients tolerance and effective bowel cleansing ability. However, new studies describe that NaP can induce colonic mucosal damage. For better characterization of these changes, we examined histologically segmental colonic biopsies from 42 patients receiving NaP bowel solution before the colonoscopy. The series includes 25 male and 17 female patients in age from 19 to 81 years (average age 46.7 ys). Clinical symptoms in 37 patients included diarrhea, constipation, bleeding and abdominal cramps. The most frequent reason for colonoscopy was suspicion of microscopic colitis. Five patients underwent endoscopy to rule out the presence of neoplasia. None of the patients took drugs before the colonoscopy. Histologically, all specimens showed mild focal edema, hyperemia and hemorrhages. In addition to edema and hemorrhage, in 26 patients (61.9%), patchy mononuclear infiltration in the upper part of lamina propria and increased epithelial cell proliferation of individual crypts were seen. Mucosal structure was normal, with partial sloughing of normal or flattened surface epithelium. In 5 patients (11.9%), some biopsy samples contained scattered neutrophilic leucocytes in the lamina propria/superficial epithelium, isolated basal cryptitis, increased proliferation and apoptosis of the crypt epithelium. In two patients with focal cryptitis (4.8%), small erosions were found. Mild basal cryptitis, increased proliferation and striking apoptosis were present in two inflammatory pseudopolyps (in two patients). In 4 patients, solitary tubular adenomas with low-grade dysplasia without any reactive changes were found. In addition, 300 hyperplastic polyps removed endoscopically after the NaP application, were examined. Two polyps (0.75%) showed cryptitis and isolated multinucleated epithelial cells in the superficial part of the crypts. Our results are similar to those previously described in other studies of colonic changes after the NaP application. It reflects probably a similarity in composition of used NaP solutions.

• MeSH
• aplikace orální MeSH
• dospělí MeSH
• fosfáty aplikace a dávkování   MeSH
• kolon účinky léků   patologie   MeSH
• kolonoskopie * MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• purgativa aplikace a dávkování   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• střevní sliznice účinky léků   patologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fosfáty MeSH
• purgativa MeSH
• sodium phosphate MeSH Prohlížeč