Advanced endoscopic imaging for dysplasia surveillance in ulcerative colitis

New Technologies in Digestive Endoscopy for Ulcerative Colitis Patients

Ulcerative colitis (UC) is a chronic inflammatory bowel disease primarily affecting the colon and rectum. Endoscopy plays a crucial role in the diagnosis and management of UC. Recent advancements in endoscopic technology, including chromoendoscopy, confocal laser endomicroscopy, endocytoscopy and the use of artificial intelligence, have revolutionized the assessment and treatment of UC patients. These innovative techniques enable early detection of dysplasia and cancer, more precise characterization of disease extent and severity and more targeted biopsies, leading to improved diagnosis and disease monitoring. Furthermore, these advancements have significant implications for therapeutic decision making, empowering clinicians to carefully consider a range of treatment options, including pharmacological therapies, endoscopic interventions and surgical approaches. In this review, we provide an overview of the latest endoscopic technologies and their applications for diagnosing and monitoring UC. We also discuss their impact on treatment decision making, highlighting the potential benefits and limitations of each technique.

Evaluation of colon mucosa using screening colonoscopy and flexible spectral imaging color enhancement in patients with long lasting ulcerative colitis

AIM

To determine which flexible spectral imaging color enhancement (FICE) channel best visualizes colon mucosa in ulcerative colitis (UC) and to compare FICE imaging with standard imaging.

METHODS

The study enrolled patients with ulcerative colitis in remission who had inflammatory bowel disease for at least 8 years. All patients underwent screening colonoscopy. The entire colon, especially the suspicious areas in terms of dysplasia, were imaged with standard endoscopy and FICE. Random and target biopsies were obtained. Histopathological diagnosis was made and image patterns were evaluated. Seven endoscopists evaluated normal, colitis, and polyp images obtained with FICE.

RESULTS

One hundred and twenty-three colon segments were evaluated and 1831 images were obtained from 18 patients. A total of 1652 images were FICE and 179 were standard images. Separate FICE images were obtained for normal colon mucosa, polypoid lesions, and colitis areas. Normal colon mucosa was best visualized using the second, sixth, and ninth FICE channel; polyps using the third, seventh, and ninth channel; and colitis using the second, third, and ninth channel. When all images were analyzed, the second and ninth channel were significantly better than the other channels. A total of 584 biopsies were obtained, including 492 (84.2%) random biopsies and 92 (15.7%) target biopsies. Random biopsies detected no dysplasia, but target biopsies detected low-grade dysplasia in three diminutive polyps.

CONCLUSION

FICE was not significantly better at dysplasia screening than the standard procedure, but it effectively detected diminutive polyps and evaluated surface patterns without using magnification. FICE might contribute to the assessment of inflammation severity in patients with UC in clinical remission. However, more extensive studies are necessary to confirm these findings.

Artificial intelligence-assisted endoscopy changes the definition of mucosal healing in ulcerative colitis

The relevance of endoscopic monitoring of ulcerative colitis (UC) has been translated into the new concept of "mucosal healing (MH)" as the therapeutic goal to achieve because a large amount of scientific data have revealed the favorable prognostic value of a healed mucosa in determining the clinical outcome of UC. Recent interest in MH has skewed toward not only endoscopic remission but also histological improvement (so called histological MH). However, we should recognize that there have been no prospectively validated endoscopic scoring systems of UC activity in previous clinical trials. Artificial intelligence (AI)-assisted endoscopy has been developed for gastrointestinal cancer surveillance. Recently, several AI-assisted endoscopic systems have been developed for assessment of MH in UC. In the future, the development of a new endoscopic scoring system based on AI might standardize the definition of MH. Therefore, "The road to an exact definition of MH in the treatment of UC has begun only now".

Effect of long-term methylene blue treatment on the composition of mouse gut microbiome and its relationship with the cognitive abilities of mice

In recent years, methylene blue (MB) has attracted considerable interest as a potential drug for the treatment of methemoglobinemia and neurodegenerative diseases. MB is active against microorganisms from various taxonomic groups. However, no studies have yet been conducted on the effect of MB on the intestinal microbiome of model animals. The aim of this work was to study the effect of different concentrations of MB on the mouse gut microbiome and its relationship with the cognitive abilities of mice. We showed that a low MB concentration (15 mg/kg/day) did not cause significant changes in the microbiome composition. The Bacteroidetes/Firmicutes ratio decreased relative to the control on the 2nd and 3rd weeks. A slight decrease in the levels Actinobacteria was detected on the 3rd week of the experiment. Changes in the content of Delta, Gamma, and Epsilonproteobacteria have been also observed. We did not find significant alterations in the composition of intestinal microbiome, which could be an indication of the development of dysbiosis or other gut dysfunction. At the same time, a high concentration of MB (50 mg/kg/day) led to pronounced changes, primarily an increase in the levels of Delta, Gamma and Epsilonproteobacteria. Over 4 weeks of therapy, the treatment with high MB concentration has led to an increase in the median content of Proteobacteria to 7.49% vs. 1.61% in the control group. Finally, we found that MB at a concentration of 15 mg/kg/day improved the cognitive abilities of mice, while negative correlation between the content of Deferribacteres and cognitive parameters was revealed. Our data expand the understanding of the relationship between MB, cognitive abilities, and gut microbiome in respect to the antibacterial properties of MB.

Comparison of Endoscopic Dysplasia Detection Techniques in Patients With Ulcerative Colitis: A Systematic Review and Network Meta-analysis

Background

We assessed the comparative efficacy of different dysplasia detection techniques in patients with ulcerative colitis (UC) through a network meta-analysis and rated the quality of evidence using GRADE approach.

Methods

Through a systematic literature review of multiple databases through June 30, 2017, we identified parallel-group randomized controlled trials (RCTs) in adults with long-standing UC undergoing surveillance colonoscopy with standard definition-white light endoscopy (SD-WLE), high-definition WLE (HD-WLE), narrow band imaging (NBI), or dye-based chromoendoscopy. The primary outcome was the total number of dysplastic lesions. Pairwise and network meta-analysis was performed; ranking was assessed using surface under the cumulative ranking (SUCRA) probabilities.

Results

Based on 8 parallel-group RCTs (924 patients), low-quality evidence supports chromoendoscopy over SD-WLE (odds ratio [OR], 2.37; 95% credible interval [CrI], 0.81-6.94) for any dysplasia detection, whereas very low-quality evidence supports using HD-WLE or NBI over SD-WLE (HD-WLE [vs SD-WLE]: OR, 1.21; 95% CrI, 0.30-4.85; NBI: OR, 1.68; 95% CrI, 0.54-5.22). Very low-quality evidence from indirect comparative analysis supports the use of chromoendoscopy over HD-WLE (OR, 1.96; 95% CrI, 0.72-5.34) or NBI (OR, 1.41; 95% CrI, 0.70-2.84) for any dysplasia detection. The number of patients with advanced neoplasia was very small, precluding meaningful analysis.

Conclusions

Although we did not find any single technique to be superior, chromoendoscopy is probably more effective than SD-WLE for detecting any dysplasia, and there is low confidence in estimates supporting its use over HD-WLE or NBI. There is very low-quality evidence to inform the comparative efficacy of these interventions in detecting advanced neoplasia or preventing future colorectal cancer. Pragmatic, parallel-group RCTs with longitudinal follow-up are warranted to inform optimal dysplasia surveillance techniques. 10.1093/ibd/izy188_video1izy188.video15789702674001.

Methylene blue MMX® tablets for chromoendoscopy. Bioavailability, colon staining and safety in healthy volunteers undergoing a full colonoscopy

Methylene blue-MMX® tablets are proposed as an aid for detection and visualisation of adenomas and carcinomas in patients undergoing colonoscopy, by improving their detection rate and highlighting the presence of the intestinal dysplastic lesions. Single total doses of 100 and 200 mg were administered to healthy volunteers undergoing a bowel cleansing preparation and a full colonoscopy to investigate the colonic staining. The pharmacokinetics of methylene blue and the safety after exposure to the tablets were also investigated. With 200 mg, the best staining, assessed as the sum of acceptable and good staining, was achieved in the ascending colon and rectosigmoid (75% subjects each), the transverse and the descending colon (approximately 63% each). Absence of staining or overstaining were reported for no colonic region of interest in any subject. Similar results were observed in the 100 mg dose group. Methylene blue blood concentrations reached a peak (C_max) in a median time (T_max) of 12 h with 100 mg and 16 h with 200 mg. AUC_0-t was 10.7 ± 6.7 μg/mLxh after 100 mg and 25.2 ± 7.4 μg/mLxh after 200 mg. Half-life ranged between 9 and 22 h after the lower dose and between 6 and 26 h after the higher dose. The cumulative urinary excretion was about 28% after 100 mg and about 39% after 200 mg up to 60 h post-dose. The overall frequency of adverse events after single dose of the test product administered along with a bowel cleansing preparation was 39%, but only one was related to the test product: abnormal transaminases. The most frequent adverse event was a transient polyuria (17%). One serious adverse event (gastrointestinal haemorrhage) led the subject to study discontinuation and hospitalisation and another subject withdrew the study due to one adverse event (haematemesis). Either event was not related to methylene blue.

Advances in endoscopic imaging in ulcerative colitis

Modern strategies for the treatment of ulcerative colitis require more accurate tools for gastrointestinal imaging to better assess mucosal disease activity and long-term prognostic clinical outcomes. Recent advances in gastrointestinal luminal endoscopy are radically changing the role of endoscopy in every-day clinical practice and research trials. Advanced endoscopic imaging techniques including high-definition endoscopes, optical magnification endoscopy, and various chromoendoscopy techniques have remarkably improved endoscopic assessment of ulcerative colitis. More recently, optical biopsy techniques with either endocytoscopy or confocal laser endomicroscopy have shown great potential in predicting several histological changes in real time during ongoing endoscopy. Here, we review current applications of advanced endoscopic imaging techniques in ulcerative colitis and present the most promising upcoming headways in this field.

Image-enhanced endoscopy is critical in the surveillance of patients with colonic IBD

Cancer risk in patients with inflammatory bowel disease (IBD) involving the colon is high and increases with time. The quality and efficacy of colonoscopic surveillance is variable. Chromoendoscopy with targeted biopsies is superior to standard white light endoscopy with random biopsies. Although commonly practiced, the technique of random colonic biopsies has poor yield for dysplasia and has little clinical consequence. Studies have shown a limited role for electronic-based image-enhanced endoscopy, including narrow band imaging, in detecting IBD dysplasia. Efforts should focus on the dissemination of the technique of chromoendoscopy in routine clinical practice through training and quality metrics.

Novel diagnostic and therapeutic techniques for surveillance of dysplasia in patients with inflammatory bowel disease

The risk for developing dysplasia and colorectal cancer in patients with longstanding inflammatory bowel disease (IBD) involving the colon is well documented. Random biopsies during white-light, standard-definition colonoscopy (33 to 50 biopsies) with or without dye spraying chromoendoscopy has been the recommended strategy in North America to detect dysplastic lesions in IBD. However, there are several limitations to this approach including poor physician adherence, poor sensitivity, increased procedure time and considerable cost. The new generation of high-definition endoscopes with electronic filter technology provide an opportunity to visualize colonic mucosal and vascular patterns in minute detail, and to identify subtle flat, multifocal, polypoid and pseudopolypoid neoplastic and non-neoplastic lesions. The application of these new technologies in IBD is slowly being adopted in clinical practice. In addition, the advent of confocal laser endomicroscopy provides an opportunity to explore real-time histology, thus redefining the understanding and characterization of the lesions in IBD. There is emerging evidence that serrated adenomas are also associated with longstanding IBD colitis and may be recognized as another important contributing factor to colorectal cancer development. The circumscribed neoplastic lesions can be treated using endoscopic therapeutic management such as mucosal resection or, especially, endoscopic submucosal dissection. This may replace panproctocolectomy in selected patients. The authors review the potential of these techniques to transform endoscopic diagnosis and therapeutic management of dysplasia in IBD.

Advanced endoscopic imaging for surveillance for dysplasia and colorectal cancer in inflammatory bowel disease: could the pathologist be further helped?

Patients with inflammatory bowel disease (IBD) have an increased risk of developing intestinal cancer. The magnitude of that increased risk as well as how best to mitigate it remain a topic of ongoing investigation in the field. It is important to quantify the risk of colorectal cancer in association with IBD. The reported risk varies widely between studies. This is partly due to the different methodologies used in the studies. Because of the limitations of surveillance strategies based on the detection of dysplasia, advanced endoscopic imaging and techniques involving the detection of alterations in mucosal antigens and genetic abnormalities are being investigated. Development of new biomarkers, predicting future occurrence of colonic neoplasia may lead to more biomarker-based surveillance. There are promising results that may lead to more efficient surveillance in IBD patients and more general acceptance of its use. A multidisciplinary approach, involving in particular endoscopists and pathologists, together with a centralized patient management, could help to optimize treatments and follow-up measures, both of which could help to reduce the IBD-associated cancer risk.

Review article: newer optical and digital chromoendoscopy techniques vs. dye-based chromoendoscopy for diagnosis and surveillance in inflammatory bowel disease

BACKGROUND

Recent innovations in gastrointestinal endoscopy have changed our traditional approach to diagnosis and therapy in patients with inflammatory bowel diseases (IBD). While traditionally used dye-based chromoendoscopy (DBC) techniques suffer from several limitations that reduce their utility in daily routine practice, newer 'dye-less' chromoendoscopy (DLC) techniques offer a great potential to overcome most of these limitations.

AIM

To review available optical and digital chromoendoscopy techniques, by critically discussing their potential for diagnostic and surveillance colonoscopy in patients with IBD.

METHODS

A literature search on the use of dye-less and dye-based chromoendoscopy in IBD patients was performed.

RESULTS

In long-standing IBD, DBC improves detection of dysplasia (diagnostic odds ratio = 17.5, 95% CI = 1.2-247.1) as well as prediction of inflammatory disease activity and extent of disease compared with standard video-colonoscopy. Narrow band imaging (NBI) shows no improvement in dysplasia detection rates compared with white-light endoscopy and DBC (P = 0.6). Moreover, NBI results in a suboptimal differentiation of dysplastic from nondysplastic lesions. No data regarding digital DLC techniques (i.e. FICE, i-scan) for dysplasia detection in IBD are yet available. Both NBI and i-scan are superior to white-light endoscopy in assessing the activity and extent of colorectal IBD.

CONCLUSIONS

Although the potential benefits of newer optical and digital dye-less chromoendoscopy techniques over traditionally used DBC are substantial, only DBC can currently be recommended to improve dysplasia detection in long-standing IBD. In contrast, DLC has the potential to quantify disease activity and mucosal healing in IBD.

Confocal laser endomicroscopy in inflammatory bowel diseases: dream or reality?

Confocal laser endomicroscopy (CLE) is a newly introduced procedure that provide real-time, high-resolution imaging of the gastrointestinal mucosa during endoscopy, allowing the visualization of the pathology of the mucosal epithelium with its cellular and subcellular structures. Recently, the use of CLE was reported in the study of colonic mucosa in patients with inflammatory bowel diseases and in particular in patients affected by ulcerative colitis. CLE has the potential to have an important role in management of inflammatory bowel diseases (IBD) patients as it can be used to assess the grading of colitis and in detection of microscopic colitis in endoscopically silent segments. Moreover, CLE can be used in surveillance programs especially in high-risk patients. Finally, CLE has been effectively used in diagnosing a biliary dysplasia/neoplasia in patients with primary sclerosing cholangitis, a pathological condition frequently associated with IBD, with a coexisting bile duct stricture.