Limited applicability of chromoendoscopy-guided confocal laser endomicroscopy as daily-practice surveillance strategy in Crohn's disease

Opening the doors of precision medicine: novel tools to assess intestinal barrier in inflammatory bowel disease and colitis-associated neoplasia

Mounting evidence underscores the pivotal role of the intestinal barrier and its convoluted network with diet and intestinal microbiome in the pathogenesis of inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CRC). Moreover, the bidirectional association of the intestinal barrier with the liver and brain, known as the gut-brain axis, plays a crucial role in developing complications, including extraintestinal manifestations of IBD and CRC metastasis. Consequently, barrier healing represents a crucial therapeutic target in these inflammatory-dependent disorders, with barrier assessment predicting disease outcomes, response to therapy and extraintestinal manifestations.New advanced technologies are revolutionising our understanding of the barrier paradigm, enabling the accurate assessment of the intestinal barrier and aiding in unravelling the complexity of the gut-brain axis. Cutting-edge endoscopic imaging techniques, such as ultra-high magnification endocytoscopy and probe-based confocal laser endomicroscopy, are new technologies allowing real-time exploration of the 'cellular' intestinal barrier. Additionally, novel advanced spatial imaging technology platforms, including multispectral imaging, upconversion nanoparticles, digital spatial profiling, optical spectroscopy and mass cytometry, enable a deep and comprehensive assessment of the 'molecular' and 'ultrastructural' barrier. In this promising landscape, artificial intelligence plays a pivotal role in standardising and integrating these novel tools, thereby contributing to barrier assessment and prediction of outcomes.Looking ahead, this integrated and comprehensive approach holds the promise of uncovering new therapeutic targets, breaking the therapeutic ceiling in IBD. Novel molecules, dietary interventions and microbiome modulation strategies aim to restore, reinforce, or modulate the gut-brain axis. These advancements have the potential for transformative and personalised approaches to managing IBD.

Role of ultra-high definition endoscopy (endomicroscopy and endocytoscopy) and real-time histologic examination in inflammatory bowel disease: Scoping review

OBJECTIVES

Confocal laser endomicroscopy (CLE) and endocytoscopy (EC) are ultra-high definition (HD) imaging modalities that enable real-time histological assessment. Although existent for nearly two decades, their role in current clinical decision making in inflammatory bowel disease management is not well defined.

METHODS

We searched PubMed using keywords ("confocal" OR "CLE" OR "endocytoscopy") AND ("IBD" OR "inflammatory bowel" OR "Crohn*" OR "Crohn's" OR "colitis ulcerosa" OR "ulcerative colitis") between 2005 and March 2023. We identified 52 studies for detailed review.

RESULTS

Confocal laser endomicroscopy was useful in real-time assessment of histologic inflammation and dysplasia characterization in both ulcerative colitis (UC) and Crohn's disease. Although CLE was associated with higher per-biopsy yield for UC-associated neoplasia (UCAN), the benefit was offset by higher procedure time, frequent equipment failure, and conflicting results on incremental yield over chromoendoscopy. Assessment of barrier dysfunction by CLE did not correlate with disease/endoscopic activity but could predict major adverse outcomes. The implications of residual CLE abnormalities in endoscopic remission remain uncertain. Ex vivo binding of labeled biologics can help in predicting biologic response in UC. EC can discriminate mucosal inflammatory cells by morphology and allows assessment of histologic activity. EC combined with pit pattern was better than pit pattern alone for UCAN. Artificial intelligence-assisted EC in UCAN needs further study.

CONCLUSION

Ultra-HD imaging in inflammatory bowel disease can be useful in assessment of UCAN, barrier dysfunction, predicting histologic remission, and biologic response. Future controlled studies are warranted to define the role of these novel technologies in clinical decision making.

Present and future of endoscopy precision for inflammatory bowel disease

Several advanced imaging techniques are now available for endoscopists managing inflammatory bowel disease (IBD) patients. These tools, including dye-based and virtual chromoendoscopy, probe-based confocal laser endomicroscopy and endocytoscopy, are increasingly innovative applications in clinical practice. They allow for a more in-depth and refined evaluation of the mucosal and vascular bowel surface, getting closer to histology. They have demonstrated a remarkable ability in assessing intestinal inflammation, histologic remission, and predicting relapse and favorable long-term outcomes. In addition, the future application of molecular endoscopy to predict biological drug responses has yielded preliminary but encouraging results. Furthermore, these techniques are crucial in detecting and characterizing IBD-related dysplasia, assisting endoscopic mucosal resection and submucosal dissection towards a surgery-sparing approach. Artificial intelligence (AI) holds great potential in this promising landscape, as it can provide an objective and reproducible assessment of inflammation and dysplasia. Moreover, it can improve the prediction of outcomes and aid in subsequent therapeutic decision-making. This review aims to summarize the promising role of state-of-the-art advanced endoscopic techniques and related AI-enabled models for managing IBD, paving the way for precision medicine.

Rediscovering histology: what is new in endoscopy for inflammatory bowel disease?

The potential of endoscopic evaluation in the management of inflammatory bowel diseases (IBD) has undoubtedly grown over the last few years. When dealing with IBD patients, histological remission (HR) is now considered a desirable target along with symptomatic and endoscopic remission, due to its association with better long-term outcomes. Consequently, the ability of endoscopic techniques to reflect microscopic findings in vivo without having to collect biopsies has become of upmost importance. In this context, a more accurate evaluation of inflammatory disease activity and the detection of dysplasia represent two mainstay targets for IBD endoscopists. New diagnostic technologies have been developed, such as dye-less chromoendoscopy, endomicroscopy, and molecular imaging, but their real incorporation in daily practice is not yet well defined. Although dye-chromoendoscopy is still recommended as the gold standard approach in dysplasia surveillance, recent research questioned the superiority of this technique over new advanced dye-less modalities [narrow band imaging (NBI), Fuji intelligent color enhancement (FICE), i-scan, blue light imaging (BLI) and linked color imaging (LCI)]. The endoscopic armamentarium might also be enriched by new video capsule endoscopy for monitoring disease activity, and high expectations are placed on the application of artificial intelligence (AI) systems to reduce operator-subjectivity and inter-observer variability. The goal of this review is to provide an updated insight on contemporary knowledge regarding new endoscopic techniques and devices, with special focus on their role in the assessment of disease activity and colorectal cancer surveillance.

Fluorescence Imaging of Breast Tumors and Gastrointestinal Cancer

Optical imaging offers a high potential for noninvasive detection and therapy of cancer in humans. Recent advances in instrumentation for diffuse optical imaging have led to new capabilities for the detection of cancer in highly scattering tissue such as the female breast. In particular, fluorescence imaging was made applicable as a sensitive technique to image molecular probes in vivo. We review recent developments in the detection of breast cancer and fluorescence-guided surgery of the breast by contrast agents available for application on humans. Detection of cancer has been investigated with the unspecific contrast agents "indocyanine green" and "omocianine" so far. Hereby, indocyanine green was found to offer high potential for the differentiation of malignant and benign lesions by exploiting vessel permeability for macromolecules as a cancer-specific feature. Tumor-specific molecular targeting and activatable probes have been investigated in clinical trials for fluorescence-guided tumor margin detection. In this application, high spatial resolution can be achieved, since tumor regions are visualized mainly at the tissue surface. As another example of superficial tumor tissue, imaging of lesions in the gastrointestinal tract is discussed. Promising results have been obtained on high-risk patients with Barrett´s esophagus and with ulcerative colitis by administering 5-aminolevulinic acid which induces accumulation of protoporphyrin IX serving as a tumor-specific fluorescent marker. Time-gated fluorescence imaging and spectroscopy are effective ways to suppress underlying background from tissue autofluorescence. Furthermore, recently developed tumor-specific molecular probes have been demonstrated to be superior to white-light endoscopy offering new ways for early detection of malignancies in the gastrointestinal tract.

Surgical Management of Dysplasia and Cancer in Inflammatory Bowel Disease

Patients with inflammatory bowel disease are at an increased risk of cancer secondary to long-standing intestinal inflammation. Surgical options must take into account the significant risk of synchronous disease at other colonic sites. Ileal pouch anal anastomosis is a viable option for patients with ulcerative colitis, but this should be restricted to early cancers that are unlikely to require preoperative or postoperative radiation treatment.

Confocal Laser Endomicroscopy in the Evaluation of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, can be effectively monitored with the use of endoscopy. The additional application of small field imaging technology such as confocal laser endomicroscopy CLE during ongoing endoscopic evaluation has led to real-time visualization of mucosal abnormalities and thus in vivo histology. The endomicroscopy (CLE) can improve IBD endoscopic evaluation by identifying seemingly normal-appearing mucosa, assessing the function of the intestinal barrier of the epithelium and vascular permeability, and by characterizing any mucosal lesions, including dysplastic lesions. CLE used during conventional endoscopy could especially facilitate the evaluation of mucosal healing in IBD. In addition, future developments in molecular imaging in IBD may optimize therapeutic approaches by identifying mucosal targets for therapy and determining the reasons for lack of response to specific therapy or subsequent loss of the response.

Diagnostic Accuracy of Endoscopic Trimodal Imaging and Chromoendoscopy for Lesion Characterization in Ulcerative Colitis

BACKGROUND

During surveillance colonoscopy of patients with long-standing ulcerative colitis [UC], a variety of dysplastic and non-dysplastic lesions are detected. The aim of this study was to address the diagnostic accuracy of endoscopic characterization of endoscopic trimodal imaging [ETMI] and chromoendoscopy [CE]. ETMI includes the combination of autofluorescence imaging [AFI], narrow band imaging [NBI] and white light endoscopy [WLE].

METHODS

This is a pre-specified additional analysis of a multi-centre, randomized controlled trial that compared AFI with CE for dysplasia detection in 210 patients with long-standing UC [FIND-UC trial]. In the AFI arm, endoscopists used the ETMI system to record AFI colour, Kudo pit pattern using NBI and WLE for lesion characterization. For AFI, purple colour and ambiguous colour combined with pit pattern type III-V on NBI was considered dysplastic. Kudo pit pattern was described in the CE arm. For pit pattern description using NBI and CE, type III-V was considered dysplastic. Histology was the reference standard.

RESULTS

In total, 52 dysplastic and 255 non-dysplastic lesions were detected. Overall sensitivity for real-time prediction of dysplasia was 76.9% (95% confidence interval [CI] 46.2-95.0) for ETMI, and 81.6% [95% CI 65.7-92.3] for CE. Overall negative predictive value [NPV] for ETMI was 96.9% [95% CI 92.0-98.8] and 94.7% [90.2-97.2] for CE.

CONCLUSIONS

Sensitivity for endoscopic differentiation of dysplastic lesions detected during surveillance of patients with long-standing UC seems limited using ETMI and CE. Future research is warranted as the high NPV indicates that these techniques are valuable for the exclusion of dysplastic lesions [NTR4062].

Screening and surveillance methods for dysplasia in inflammatory bowel disease patients: Where do we stand?

Patients with long-standing ulcerative colitis (UC) and extensive Crohn’s colitis (CC) are at increased risk for dysplasia and colorectal cancer (CRC). Several studies have shown that UC extending proximal to the rectum, CC involving at least 1/3 of the colon, co-existence of primary sclerosing cholangitis, undetermined or unclassified colitis, family history of CRC and young age at diagnosis appear to be independent risk factors for inflammatory bowel disease (IBD) - related CRC. Therefore, screening and surveillance for CRC in IBD patients is highly recommended by international and national guidelines, whilst colonoscopy remains the unequivocal tool in order to detect potentially resectable dysplastic lesions or CRC at an early stage. Although the importance of screening and surveillance is widely proven, there is a controversy regarding the time of the first colonoscopy and the criteria of who should undergo surveillance. In addition, there are different recommendations among scientific societies concerning which endoscopic method is more efficient to detect dysplasia early, as well as the terminology for reporting visible lesions and the management of those lesions. This article concisely presents the main endoscopic methods and techniques performed for detecting dysplasia and CRC surveillance in patients with IBD focusing on their evidence-based accuracy and efficiency, as well as their cost-effectiveness. Finally, newer methods are mentioned, highlighting their applicability in daily endoscopic practice.

Modern Endoscopic Imaging in Diagnosis and Surveillance of Inflammatory Bowel Disease Patients

Endoscopy remains the most important diagnostic and monitoring modality in the management of inflammatory bowel disease. Advances in imaging have progressively added new tools into the armamentarium of endoscopists with the goal of more accurate, sensitive, and accessible visual diagnoses for the benefit of patients with gastrointestinal diseases. Here, we review the relevant literature regarding commonly used endoscopic techniques (dye-based and digital chromoendoscopy, high-definition endoscopy, capsule endoscopy, and endosonography), as well as advanced and experimental technologies (full-spectrum endoscopy, endocytoscopy, autofluorescence, laser endoscopy, and endomicroscopy, including molecular imaging), applicable to inflammatory bowel diseases and emerging for implementation into everyday practice. Additionally, we discuss future directions and techniques as candidates for a superior inflammation imaging in the diagnosis and prediction of therapeutic response.

Colonic lesion characterization in inflammatory bowel disease: A systematic review and meta-analysis

AIM

To perform a systematic review and meta-analysis for the diagnostic accuracy of in vivo lesion characterization in colonic inflammatory bowel disease (IBD), using optical imaging techniques, including virtual chromoendoscopy (VCE), dye-based chromoendoscopy (DBC), magnification endoscopy and confocal laser endomicroscopy (CLE).

METHODS

We searched Medline, Embase and the Cochrane library. We performed a bivariate meta-analysis to calculate the pooled estimate sensitivities, specificities, positive and negative likelihood ratios (+LHR, -LHR), diagnostic odds ratios (DOR), and area under the SROC curve (AUSROC) for each technology group. A subgroup analysis was performed to investigate differences in real-time non-magnified Kudo pit patterns (with VCE and DBC) and real-time CLE.

RESULTS

We included 22 studies [1491 patients; 4674 polyps, of which 539 (11.5%) were neoplastic]. Real-time CLE had a pooled sensitivity of 91% (95%CI: 66%-98%), specificity of 97% (95%CI: 94%-98%), and an AUSROC of 0.98 (95%CI: 0.97-0.99). Magnification endoscopy had a pooled sensitivity of 90% (95%CI: 77%-96%) and specificity of 87% (95%CI: 81%-91%). VCE had a pooled sensitivity of 86% (95%CI: 62%-95%) and specificity of 87% (95%CI: 72%-95%). DBC had a pooled sensitivity of 67% (95%CI: 44%-84%) and specificity of 86% (95%CI: 72%-94%).

CONCLUSION

Real-time CLE is a highly accurate technology for differentiating neoplastic from non-neoplastic lesions in patients with colonic IBD. However, most CLE studies were performed by single expert users within tertiary centres, potentially confounding these results.

Imaging of Mucosal Inflammation: Current Technological Developments, Clinical Implications, and Future Perspectives

In recent years, various technological developments markedly improved imaging of mucosal inflammation in patients with inflammatory bowel diseases. Although technological developments such as high-definition-, chromo-, and autofluorescence-endoscopy led to a more precise and detailed assessment of mucosal inflammation during wide-field endoscopy, probe-based and stationary confocal laser microscopy enabled in vivo real-time microscopic imaging of mucosal surfaces within the gastrointestinal tract. Through the use of fluorochromes with specificity against a defined molecular target combined with endoscopic techniques that allow ultrastructural resolution, molecular imaging enables in vivo visualization of single molecules or receptors during endoscopy. Molecular imaging has therefore greatly expanded the clinical utility and applications of modern innovative endoscopy, which include the diagnosis, surveillance, and treatment of disease as well as the prediction of the therapeutic response of individual patients. Furthermore, non-invasive imaging techniques such as computed tomography, magnetic resonance imaging, scintigraphy, and ultrasound provide helpful information as supplement to invasive endoscopic procedures. In this review, we provide an overview on the current status of advanced imaging technologies for the clinical non-invasive and endoscopic evaluation of mucosal inflammation. Furthermore, the value of novel methods such as multiphoton microscopy, optoacoustics, and optical coherence tomography and their possible future implementation into clinical diagnosis and evaluation of mucosal inflammation will be discussed.

Role of Advanced Endoscopic Imaging Techniques in the Management of Inflammatory Bowel Disease

Endoscopy plays a crucial role in the management of inflammatory bowel disease (IBD) in terms of diagnosis, monitoring of mucosal status, and surveillance of colitis-associated neoplasia. Mucosal healing evaluated by endoscopy has been recognized as the target of treatment in the era of powerful biologics therapy. The optimal modality for identifying dysplasia in IBD has yet to be well defined. Increasing progress has recently been made in endoscopic technologies to more accurately assess mucosal inflammation and more effectively detect dysplasia. Here we review the data of advanced endoscopic imaging techniques such as chromoendoscopy, virtual chromoendoscopy, endocytoscopy, and confocal laser endomicroscopy in the management of IBD.

Detection of colonic dysplasia in patients with ulcerative colitis using a targeted fluorescent peptide and confocal laser endomicroscopy: A pilot study

Aim

Targeted molecular probes have been used to detect sporadic colonic dysplasia during confocal laser endomicroscopy (CLE) with promising results. This is a feasibility pilot study aiming to assess the potential role of CLE combined with a fluorescent-labeled peptide to stain and detect dysplasia associated with Ulcerative Colitis.

Method

A phage-derived heptapeptide with predicted high binding affinity for dysplastic tissue, was synthesized and labeled with fluorescein. Eleven lesions with suspected dysplasia at endoscopy were excised from nine patients with long-standing ulcerative colitis. Specimens were sprayed with the peptide and examined by CLE. The CLE images were then compared to the corresponding histological sections.

Results

At definitive histology, 4 lesions were diagnosed as inflammatory polyps, 6 as dysplastic lesions and one as invasive cancer. In inflammatory polyps, the fluorescence signal came from peri-cryptal spaces and crypt lumen due to passive accumulation of the peptide in these areas. Dysplasia was associated with active binding of the peptide to dysplastic colonocytes.

Conclusion

Ex vivo staining of ulcerative colitis-associated dysplasia using a fluorescent labeled molecular probe and CLE is feasible. In vivo studies on larger populations are required to evaluate the safety and the effective contribution of molecular probes in cancer surveillance of ulcerative colitis.

Advanced endoscopy imaging in inflammatory bowel diseases

BACKGROUND AND AIMS

Rapid assessment of mucosal inflammation is of crucial importance for the initial diagnosis and the assessment of mucosal healing in inflammatory bowel disease (IBD). Moreover, the identification of intraepithelial neoplasias in IBD is of key relevance for clinical management. Here, we systematically analyzed the utility of advanced endoscopic imaging techniques for optimized diagnosis in IBD.

METHODS

PubMed/Medline, Web of Knowledge, and Cochrane library were searched twice for diagnostic studies on advanced endoscopic imaging in IBD. Clinical and technical information was retrieved and subsequently analyzed. Main outcome parameters consisted of the quality of the results, adverse events, and diagnostic yield.

RESULTS

Fifty-six clinical studies with a total of 3296 patients were selected for final analysis. Filter technologies permitted a more detailed analysis of mucosal inflammation in IBD. In spite of substantial heterogeneity across studies, dye-based chromoendoscopy with targeted biopsy sampling yielded higher detection rates of intraepithelial neoplasias in ulcerative colitis as compared with white-light endoscopy with random biopsy sampling. Moreover, endocytoscopy and endomicroscopy allowed subsurface imaging of inflamed or neoplastic mucosa in IBD at subcellular resolution. Finally, endomicroscopy-aided molecular imaging enabled the identification of membrane-bound tumor necrosis factor on mucosal cells as a potential driver of disease activity in Crohn's disease. No relevant adverse events were reported.

CONCLUSIONS

Advanced endoscopic imaging technologies are feasible, safe, and partially effective tools for detailed diagnosis of mucosal inflammation and detection of neoplasias in IBD. Results obtained from these advanced techniques may provide a rational basis for individualized, optimized therapy for IBD patients.

Endomicroscopy and Molecular Tools to Evaluate Inflammatory Bowel Disease

Endoscopy is an essential tool for effective care of patients with inflammatory bowel disease (IBD), including Crohn disease and ulcerative colitis. The newest endoscopic small-field imaging technologies with confocal endomicroscopy have allowed real-time imaging of gastrointestinal mucosal during ongoing endoscopic evaluation and in vivo histology. Thus, endomicroscopy has a potential to further enhance the endoscopic evaluation of IBD. Advances in molecular in vivo imaging in IBD may be used not only to better understand the pathophysiology of IBD but also to guide optimized therapy and thus to allow a personalized, new approach to the IBD management.

Diagnostic yield of endomicroscopy for dysplasia in primary sclerosing cholangitis associated inflammatory bowel disease: a feasibility study

BACKGROUND AND STUDY AIMS

Primary sclerosing cholangitis associated inflammatory bowel disease (PSC-IBD) is characterized by a high risk of colorectal dysplasia. Surveillance colonoscopies with random biopsies have doubtful power for dysplasia detection. Our aim was to prospectively investigate the feasibility and efficacy of pCLE in surveillance colonoscopies in patients with PSC-IBD.

PATIENTS AND METHODS

Sixty-nine patients with PSC-IBD underwent colonoscopy in 2 steps. On the way from rectum to cecum, the mucosa was inspected with high definition endoscopy (HDE) and random biopsies were taken according to the standard routine. On the way from cecum to rectum, fluorescein-enhanced pCLE and chromoendoscopy were performed. Regions where random biopsies had been taken, as well as visible lesions, were examined with pCLE and targeted biopsies were taken of lesions suspicious for dysplasia. Two investigators, blinded to histology and endoscopy results, analyzed all pCLE videos off-line.

RESULTS

Nineteen biopsies obtained in 13 patients (17 targeted biopsies, 2 random biopsies) revealed the presence of low-grade dysplasia. Thirteen lesions with dysplasia were endoscopically visible but by using pCLE-targeted biopsies, additional endoscopically invisible dysplasias in 4 biopsies obtained from 3 patients were detected. The sensitivity, specificity, and accuracy of pCLE in predicting dysplasia were respectively 89 % (95 % CI: 65 - 98), 96 % (95 % CI: 94 - 97), and 96 % (95 % CI: 94 - 97). pCLE showed a good performance for differentiating neoplastic from non-neoplastic mucosa with negative predictive value of 99 %.

CONCLUSIONS

pCLE in PSC-IBD surveillance is feasible and may be a good complement to HDE. Future research should aim at elucidating whether real-time pCLE is applicable in PSC-IBD surveillance.