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

Moxifloxacin promotes two-photon microscopic imaging for discriminating different stages of DSS-induced colitis on mice

BACKGROUND

Accurate diagnosis of patients with ulcerative colitis (UC) can reduce their risk of developing colorectal cancer. This study intended to explore whether moxifloxacin, an agent with fluorescence potential, could promote two-photon microscopy (TPM) diagnosis for mice with dextran sodium sulfate (DSS)-induced colitis, which could imitate human UC.

METHODS

32 Balb/c mice were randomly divided into 4 groups: control, acute colitis, remission colitis and chronic colitis. Fluorescence parameters, imaging performance, and tissue features of different mouse models were compared under moxifloxacin-assisted TPM and label-free TPM.

RESULTS

Excitation wavelength of 720 nm and moxifloxacin labeling time of 2 min was optimal for moxifloxacin-assisted TPM. With moxifloxacin labeling for colonic tissues, excitation power was decreased to 1/10 of that without labeling while fluorescence intensity was increased to 10-fold of that without labeling. Photobleaching was negligible after moxifloxacin labeling and moxifloxacin fluorescence kept stable within 2 h. Compared with the control group, moxifloxacin fluorescence was reduced in the three colitis groups (P < 0.05). Meanwhile, the proportion of enhanced moxifloxacin fluorescence regions was (22.4 ± 1.6)%, (7.7 ± 1.0)%, (13.5 ± 1.7)% and (5.0 ± 1.3)% in the control, acute, remission and chronic groups respectively, with significant reduction in the three colitis groups (P < 0.05). Besides, variant tissue features of experimental colitis models were presented under moxifloxacin-assisted TPM, such as crypt opening, glandular structure, adjacent glandular space and moxifloxacin distribution.

CONCLUSIONS

With unique biological interaction between moxifloxacin and colonic mucosa, moxifloxacin-assisted TPM imaging is feasible and effective for accurate diagnosis of different stages of experimental colitis.

The Utility of Narrow-Band Imaging International Colorectal Endoscopic Classification in Predicting the Histologies of Diminutive Colorectal Polyps Using I-Scan Optical Enhancement: A Prospective Study

(1) Background: This study aimed to evaluate the accuracy of predicting the histology of diminutive colonic polyps (DCPs) (≤5 mm) using i-scan optical enhancement (OE) based on the narrow-band imaging international colorectal endoscopic (NICE) classification. The study compared the diagnostic accuracy between experts who were already familiar with the NICE classification and trainees who were not, both before and after receiving brief training on the NICE classification. (2) Method: This prospective, single-center clinical trial was conducted at the Dong-A University Hospital from March 2020 to August 2020 and involved two groups of participants. The first group comprised two experienced endoscopists who were proficient in using i-scan OE and had received formal training in optical diagnosis and dye-less chromoendoscopy (DLC) techniques. The second group consisted of three endoscopists in the process of training in internal medicine at the Dong-A University Hospital. Each endoscopist examined the polyps and evaluated them using the NICE classification through i-scan OE. The results were not among the participants. Trained endoscopists were divided into pre- and post-training groups. (3) Results: During the study, a total of 259 DCPs were assessed using i-scan OE by the two expert endoscopists. They made real-time histological predictions according to the NICE classification criteria. For the trainee group, before training, the area under the receiver operating characteristic curves (AUROCs) for predicting histopathological results using i-scan OE were 0.791, 0.775, and 0.818. However, after receiving training, the AUROCs improved to 0.935, 0.949, and 0.963, which were not significantly different from the results achieved by the expert endoscopists. (4) Conclusions: This study highlights the potential of i-scan OE, along with the NICE classification, in predicting the histopathological results of DCPs during colonoscopy. In addition, this study suggests that even an endoscopist without experience in DLC can effectively use i-scan OE to improve diagnostic performance with only brief training.

Next-Generation Endoscopy in Inflammatory Bowel Disease

Endoscopic healing is recognized as a primary treatment goal in Inflammatory Bowel Disease (IBD). However, endoscopic remission may not reflect histological remission, which is crucial to achieving favorable long-term outcomes. The development of new advanced techniques has revolutionized the field of IBD assessment and management. These tools can accurately assess vascular and mucosal features, drawing endoscopy closer to histology. Moreover, they can enhance the detection and characterization of IBD-related dysplasia. Given the persistent challenge of interobserver variability, a more standardized approach to endoscopy is warranted, and the integration of artificial intelligence (AI) holds promise for addressing this limitation. Additionally, although molecular endoscopy is still in its infancy, it is a promising tool to forecast response to therapy. This review provides an overview of advanced endoscopic techniques, including dye-based and dye-less chromoendoscopy, and in vivo histological examinations with probe-based confocal laser endomicroscopy and endocytoscopy. The remarkable contribution of these tools to IBD management, especially when integrated with AI, is discussed. Specific attention is given to their role in improving disease assessment, detection, and characterization of IBD-associated lesions, and predicting disease-related outcomes.

Phthalocyanine-Blue Nanoparticles for the Direct Visualization of Tumors with White Light Illumination

The current standard of care for colon cancer surveillance relies heavily on white light endoscopy (WLE). However, dysplastic lesions that are not visible to the naked eye are often missed when conventional WLE equipment is used. Although dye-based chromoendoscopy shows promise, current dyes cannot delineate tumor tissues from surrounding healthy tissues accurately. The goal of the present study was to screen various phthalocyanine (PC) dye-loaded micelles for their ability to improve the direct visualization of tumor tissues under white light following intravenous administration. Zinc PC (tetra-tert-butyl)-loaded micelles were identified as the optimal formulation. Their accumulation within syngeneic breast tumors led the tumors to turn dark blue in color, making them clearly visible to the naked eye. These micelles were similarly able to turn spontaneous colorectal adenomas in Apc+/Min mice a dark blue color for easy identification and could enable clinicians to more effectively detect and remove colonic polyps.

Incremental Detection Rate of Dysplasia and Sessile Serrated Polyps/Adenomas Using Narrow-Band Imaging and Dye Spray Chromoendoscopy in Addition to High-Definition Endoscopy in Patients with Long-Standing Extensive Ulcerative Colitis: Segmental Tandem Endoscopic Study

High-definition (HD) endoscopy is recommended in surveillance colonoscopy for detecting dysplasia in patients with ulcerative colitis (UC). Dye-spray chromoendoscopy (DCE) and narrow-band imaging (NBI) are often used as adjunctive techniques of white-light endoscopy (WLE) in real-world practice. However, the incremental detection ability of DCE and NBI added to HD-WLE for dysplasia and serrated lesions has not yet been evaluated using tandem endoscopy in patients with long-standing extensive UC. We enrolled patients with extensive UC for >8 years who were in clinical remission (partial Mayo score < 2) at the Samsung Medical Center in Seoul, Republic of Korea. HD-WLE was performed first. Subsequently, HD-NBI and HD-DCE with indigo carmine were performed using the segmental tandem colonoscopy technique. A total of 40 patients were eligible, and data obtained from 33 patients were analyzed. The incremental detection rates (IDRs) for dysplasia and serrated lesions were calculated. HD-WLE detected three dysplasia and five sessile serrated adenomas/polyps (SSAs/Ps). HD-NBI and HD-DCE did not detect additional dysplasia (IDR = 0%; 95% confidence interval (CI): 0-56.2%). HD-NBI identified one missed SSA/P (IDR = 7.7%; 95% CI: 1.4-33.3%), and HD-DCE detected seven missed SSAs/Ps (IDR = 53.9%; 95% CI: 29.1-76.8%). Logistic regression found that HD-DCE increased the detection of SSAs/Ps compared to HD-WLE and/or HD-NBI (odds ratio (OR) = 3.16, 95% CI: 0.83-11.92, p = 0.08). DCE in addition to HD-WLE improved the detection of SSAs/Ps, but not dysplasia, in patients with long-standing extensive UC.

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.

Adherence to Recommendations and Quality of Endoscopic Colorectal Cancer Surveillance in Long-Standing Ulcerative Colitis

Background

Long-standing ulcerative colitis has been associated with an increased risk of colorectal cancer (CRC). Current guidelines recommend endoscopic CRC screening after 8 years of disease duration. The objectives of our study were to assess the adherence to recommendations and the quality of endoscopic procedure in long-standing ulcerative colitis.

Methods

This is a retrospective cohort study. We selected patients included in the Swiss IBD cohort with a disease duration of ≥8 years and an extension above the rectosigmoid junction. The complementary medical chart review focused on endoscopy and associated histological reports in 8 Swiss centers. Descriptive analyses focused on patients and their colonoscopies.

Results

309 colonoscopies were conducted among 116 patients with the following characteristics: women 47%, mean age at diagnosis 31 years, and pancolitis disease extent in 65.5% of cases; 38.8% of patients had a first screening colonoscopy <8 years, 13.8% between 8 and 10 years, and 47.4% >10 years. Cecal intubation was performed in 94.5% of cases, and bowel preparation was good to excellent in 61.5% of endoscopies. Chromoendoscopy was used in 7.4% of cases, and the mean withdrawal time was 16.4 min. Dysplasia was found in 6.2% of cases.

Conclusion

Despite current international recommendations, a significant number of patients did not receive a proper endoscopic surveillance. An increased use of chromoendoscopy, monitoring of withdrawal time, and appropriate bowel preparation would increase the quality of CRC screening. The adherence to screening guidelines and endoscopic quality should be promoted and standardized.

A novel endoscopic imaging system for quantitative evaluation of colonic mucosal inflammation in patients with quiescent ulcerative colitis

Background and study aims  Mucosal healing (MH) is associated with clinical outcome in ulcerative colitis (UC) patients. In most clinical trials, a Mayo endoscopic subscore (MES) of 0 or 1 is defined as MH. However, several recent studies have reported that clinical outcome is different between UC patients with MES 0 and those with MES 1. In addition, the MES is subjective and may differ among endoscopists. Therefore, a repeatable and objective scoring system is required to distinguish MES 0 from MES 1, even in clinically quiescent UC. Here, we assessed the usefulness of new image-enhancing endoscopic technology, the i-scan TE-c, to quantitatively evaluate colonic inflammation in patients with quiescent UC. Methods  We retrospectively reviewed the data from 52 UC patients in clinical remission who had undergone routine colonoscopy with standard white light. The white-light images were reassessed using the new system, and the degree of colonic mucosal inflammation was quantified according to the MAGIC (Mucosal Analysis of Inflammatory Gravity by i-scan TE-c Image) score. We used the i-scan TE-c system to investigate the association among the MAGIC score, MES, and histologic activity (Geboes score). Results  The MAGIC score was significantly higher in the MES 1 group than in the MES 0 group ( P  = 0.0034). The MAGIC score significantly correlated with the Geboes score ( P  = 0.015). Conclusions  Our novel image-enhancing endoscopic system was useful for objective and quantitative evaluation of MH in patients with quiescent UC. Further clinical studies using this imaging system are required to confirm its clinical benefit for the management of UC patients.

Practical fecal calprotectin cut-off value for Japanese patients with ulcerative colitis

AIM

To determine appropriate fecal calprotectin cut-off values for the prediction of endoscopic and histologic remission in Japanese patients with ulcerative colitis (UC).

METHODS

We performed a cross-sectional observational study of 131 Japanese patients with UC and measured fecal calprotectin levels by fluorescence enzyme immunoassay. The clinical activity of UC was assessed with the partial Mayo score (PMS). Relapse was defined as increase of PMS by 2 points or more in stool frequency or rectal bleeding subscore. The endoscopic and histologic activities of UC were evaluated in 50 patients within a 2-mo period from fecal sampling. Endoscopic activity was determined by Mayo endoscopic subscore, Rachmilewitz endoscopic index, and ulcerative colitis endoscopic index of severity. The histologic grade of inflammation was evaluated with biopsy specimens obtained from the endoscopically most severely inflamed site, according to the scheme by Matts grade and Riley’s score.

RESULTS

Fecal calprotectin levels varied from 1-20783 μg/g. There was a significant correlation between the partial Mayo score and fecal calprotectin levels (r = 0.548, P < 0.001). In 50 patients who underwent colonoscopy with biopsy, levels were significantly correlated with the Mayo endoscopic subscore (r = 0.574, P < 0.001), Rachmilewitz endoscopic index (r = 0.628, P < 0.001), ulcerative colitis endoscopic index of severity (r = 0.613, P < 0.001), Riley’s histologic score (r = 0.400, P = 0.006), and Matts grade (r = 0.586, P < 0.001). Receiver-operating characteristic analyses identified the best cut-off value for the prediction of endoscopic remission as 288 μg/g, with an area under the curve of 0.777 or 0.823, while that for histologic remission was 123 or 125 μg/g, with an AUC of 0.881 or 0918, respectively. Of the 131 study patients, 88 patients in clinical remission were followed up 6 mo. During the follow-up period, 19 patients relapsed. The best fecal calprotectin cut-off value for predicting relapse was 175 μg/g.

CONCLUSION

Fecal calprotectin is a predictive biomarker for endoscopic and histologic remission in Japanese patients with UC.

Endoscopy in Pediatric Inflammatory Bowel Disease: A Position Paper on Behalf of the Porto IBD Group of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition

Endoscopy is a central tool for the evaluation and management of inflammatory bowel disease (IBD). In the last few decades, gastrointestinal (GI) endoscopy has undergone significant technological developments including availability of pediatric-size equipment, enabling comprehensive investigation of the GI tract in children. Simultaneously, professional organization of GI experts have developed guidelines and training programs in pediatric GI endoscopy. This prompted the Porto Group on Pediatric IBD of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition to develop updated guidelines on the role of GI endoscopy in pediatric IBD, specifically taking into considerations of recent advances in the diagnosis, disease stratification, and novel therapeutic targets in these patients.

Effect of Chromoendoscopy Filters on Visualization of KTP Laser-Associated Tissue Changes: A Cadaveric Animal Model

Standard KTP laser (potassium titanyl phosphate) wavelength-specific protective eyewear often impairs visualization of tissue changes during laser treatment. This sometimes necessitates eyewear removal to evaluate tissue effects, which wastes time and poses safety concerns. The objective was to determine if "virtual" or "electronic" chromoendoscopy filters, as found on some endoscopy platforms, could alleviate the restricted visualization inherent to protective eyewear. A KTP laser was applied to porcine laryngeal tissue and recorded via video laryngoscopy with 1 optical (Olympus Narrow Band Imaging) and 8 digital (Pentax Medical I-scan) chromoendoscopy filters. Videos were viewed by 11 otolaryngologists wearing protective eyewear. Using a discrete visual analog scale, they rated each filter on its ability to improve visualization,. No filter impaired visualization; 5 of 9 improved visualization. Based on statistical significance, the number of positive responses, and the lack of negative responses, narrow band imaging and the I-scan tone enhancement filter for leukoplakia performed best. These filters could shorten procedure time and improve safety; therefore, further clinical evaluation is warranted.

Raman fiber-optical method for colon cancer detection: Cross-validation and outlier identification approach

Endoscopy plays a major role in early recognition of cancer which is not externally accessible and therewith in increasing the survival rate. Raman spectroscopic fiber-optical approaches can help to decrease the impact on the patient, increase objectivity in tissue characterization, reduce expenses and provide a significant time advantage in endoscopy. In gastroenterology an early recognition of malign and precursor lesions is relevant. Instantaneous and precise differentiation between adenomas as precursor lesions for cancer and hyperplastic polyps on the one hand and between high and low-risk alterations on the other hand is important. Raman fiber-optical measurements of colon biopsy samples taken during colonoscopy were carried out during a clinical study, and samples of adenocarcinoma (22), tubular adenomas (141), hyperplastic polyps (79) and normal tissue (101) from 151 patients were analyzed. This allows us to focus on the bioinformatic analysis and to set stage for Raman endoscopic measurements. Since spectral differences between normal and cancerous biopsy samples are small, special care has to be taken in data analysis. Using a leave-one-patient-out cross-validation scheme, three different outlier identification methods were investigated to decrease the influence of systematic errors, like a residual risk in misplacement of the sample and spectral dilution of marker bands (esp. cancerous tissue) and therewith optimize the experimental design. Furthermore other validations methods like leave-one-sample-out and leave-one-spectrum-out cross-validation schemes were compared with leave-one-patient-out cross-validation. High-risk lesions were differentiated from low-risk lesions with a sensitivity of 79%, specificity of 74% and an accuracy of 77%, cancer and normal tissue with a sensitivity of 79%, specificity of 83% and an accuracy of 81%. Additionally applied outlier identification enabled us to improve the recognition of neoplastic biopsy samples.

Surveillance strategies for colitis-associated cancer: state of the art and future perspectives

Colitis-associated cancer (CAC) represents a concrete risk of morbidity and mortality in patients with long lasting inflammatory bowel diseases. Surveillance colonoscopy is a rapidly evolving research field with profound changes from the traditional approach based on scheduled controls and random biopsy protocols. Areas covered: A literature search was performed using PubMed/Embase to review the latest evidence supporting the need for surveillance colonoscopy. By focusing on the most promising recent advances in this field, we provide a state-of-the-art overview of the current gold standards for the diagnosis and management of colitis-associated dysplasia. Expert commentary: Evidence-based and emerging data have questioned the efficacy and effectiveness of both standard surveillance colonoscopy and random biopsy protocols. The latest guidelines endorse early initiation of surveillance programs, risk-profiling assessment of colonoscopy intervals and standardized use of advanced imaging modalities to detect early dysplasia. Current trends clearly reveal increased attention to direct visualization and endoscopic management of visible dysplastic lesions, even in patients with longstanding colitis. Emerging technological advances in gastrointestinal endoscopy are expected to change the endoscopic surveillance protocols in the near future.

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.

Beyond endoscopic mucosal healing in UC: histological remission better predicts corticosteroid use and hospitalisation over 6 years of follow-up

BACKGROUND

Endoscopic mucosal healing is an established treatment target for UC, yet the value of achieving histological remission remains unclear.

AIMS

To evaluate histological remission compared to endoscopic mucosal healing for predicting patient outcomes in UC.

METHODS

Blinded assessment of endoscopic and histological measures of disease activity was performed on patients with established UC at baseline. Concordance and prognostic values of endoscopic mucosal healing (defined by Baron score ≤1) and histological remission (defined by Truelove and Richards' index) for predicting outcomes of corticosteroid use, hospitalisation and colectomy were determined over a median 6 years follow-up, including κ statistics and Cox regression multivariate analysis.

RESULTS

91 patients with UC were followed up for a median 72 months (IQR 54-75 months). Overall, concordance between endoscopic and histological remission was moderate (κ=0.56, 95% CI 0.36 to 0.77); 24% patients had persistent inflammation despite endoscopic remission. Histological remission predicted corticosteroid use and acute severe colitis requiring hospitalisation over the follow-up period (HR 0.42 (0.2 to 0.9), p=0.02; HR 0.21 (0.1 to 0.7), p=0.02; respectively), whereas endoscopic mucosal healing did not (HR 0.86, 95% CI 0.5 to 1.7, p0.65; HR 0.83 95% CI 0.3 to 2.4, p0.74; respectively).

CONCLUSIONS

Histological remission is a target distinct from endoscopic mucosal healing in UC and better predicts lower rates of corticosteroid use and acute severe colitis requiring hospitalisation, over a median of 6 years of follow-up. Our findings support the inclusion of histological indices in both UC clinical trials and practice, towards a target of 'complete remission'.

Detection of Early Murine Colorectal Cancer by MMP-2/-9-Guided Fluorescence Endoscopy

BACKGROUND

Patients with ulcerative colitis are at increased risk for colorectal cancer and endoscopic surveillance is mandatory. Matrix metalloproteinases (MMPs)-2 and -9 activities are increased in malignant colonic mucosa. The aim of the study was to evaluate molecular imaging of MMP-2/-9 by fluorescence endoscopy (FE) for early tumor detection.

METHODS

Colorectal cancer in mice (n = 28) was induced by azoxymethane and dextran sodium sulfate. Twenty-four hours after intravenous injection of a nonpeptidic, Cy5.5-labeled MMP-selective tracer, tumor development was assessed in vivo by white light endoscopy and FE. Topical administration of the tracer was also investigated (after 5 minutes and 24 hours). Colonic tumors were evaluated ex vivo by fluorescence reflectance imaging, immunohistochemistry, Western blot analysis, and zymography.

RESULTS

Imaging of MMP-2/-9 expression by FE achieved a significantly higher contrast of the fluorescence signal in colonic adenomas compared with the adjacent nonmalignant mucosa (P < 0.001). Fluorescence reflectance imaging detected a significantly higher tracer uptake in adenoma compared with healthy mucosa (P < 0.001) and revealed a tumor size-dependent increase of tracer uptake (P < 0.01). Topical tracer administration did not facilitate tumor detection. Immunohistochemistry, Western blot analysis, and zymography indicated higher levels of MMP-2 and -9 in high-grade dysplasia and pT1 tumors ex vivo.

CONCLUSIONS

MMP-2/-9 expression was significantly increased in colorectal neoplasia. FE allows direct visualization of a prognostic parameter (here MMP-2/-9) on a molecular level and may improve the characterization of colorectal lesions and the adenoma detection rate in the future.

High-definition endoscopy with digital chromoendoscopy for histologic prediction of distal colorectal polyps

Background

Distal diminutive colorectal polyps are common and accurate endoscopic prediction of hyperplastic or adenomatous polyp histology could reduce procedural time, costs and potential risks associated with the resection. Within this study we assessed whether digital chromoendoscopy can accurately predict the histology of distal diminutive colorectal polyps according to the ASGE PIVI statement.

Methods

In this prospective cohort study, 224 consecutive patients undergoing screening or surveillance colonoscopy were included. Real time histology of 121 diminutive distal colorectal polyps was evaluated using high-definition endoscopy with digital chromoendoscopy and the accuracy of predicting histology with digital chromoendoscopy was assessed.

Results

The overall accuracy of digital chromoendoscopy for prediction of adenomatous polyp histology was 90.1 %. Sensitivity, specificity, positive and negative predictive values were 93.3, 88.7, 88.7, and 93.2 %, respectively. In high-confidence predictions, the accuracy increased to 96.3 % while sensitivity, specificity, positive and negative predictive values were calculated as 98.1, 94.4, 94.5, and 98.1 %, respectively. Surveillance intervals with digital chromoendoscopy were correctly predicted with >90 % accuracy.

Conclusions

High-definition endoscopy in combination with digital chromoendoscopy allowed real-time in vivo prediction of distal colorectal polyp histology and is accurate enough to leave distal colorectal polyps in place without resection or to resect and discard them without pathologic assessment. This approach has the potential to reduce costs and risks associated with the redundant removal of diminutive colorectal polyps.

Trial registration

ClinicalTrials NCT02217449.

Current issues in inflammatory bowel disease neoplasia

Recent histological criteria and developments in the field of endoscopic imaging have led to higher detection rates of neoplasms in ulcerative colitis. Once a lesion is detected, endoscopic resection is recommended to guide subsequent surveillance or therapy and to gain adequate material for histological diagnosis. Further management is based on the grade of neoplasia and on whether the neoplasia is categorized as sporadic or colitis-associated. Nevertheless it may sometimes be difficult to distinguish colitis-associated neoplasms from sporadic neoplasms. A better way to report this may be ultimately classified. Here, we review endoscopic and histological parameters to help to differentiate colitis-associated neoplasia from sporadic lesions and discuss pathogenesis and therapeutic options.

Red flag imaging in Barrett's esophagus: does it help to find the needle in the haystack?

Esophageal Adenocarcinoma (EAC) has suffered a sharp increase on its incidence for the last decades, and it is associated with a poor prognosis. Barrett's Esophagus (BE) is the most important identifiable risk factor for the progression to esophageal adenocarcinoma. The key to prevent and provide a curative treatment of esophageal adenocarcinoma is the detection and eradication of early neoplasia in patients with esophagus. Endoscopic surveillance is evolving from a blind or random four quadrant biopsies protocol (Seattle protocol) to a more targeted approach. A detailed white light examination with high-resolution endoscopy is the cornerstone for recognition of early neoplastic lesions in BE. Additional imaging modalities may enhance targeting of lesions or provide more information at a focused level. There are emerging data that some of these new modalities can increase the yield of detecting dysplasia, although its routine use has yet to be validated.

Assessment of mucosal healing in inflammatory bowel disease: review

BACKGROUND AND AIMS

Mucosal healing is an important treatment end-point in inflammatory bowel disease, and achieving mucosal healing has been demonstrated to improve disease-related outcomes. Considerable uncertainty exists, however, regarding the optimal approach for the assessment of mucosal healing.

AIMS

To compare currently available diagnostic tools for the assessment of mucosal healing and outline the ideal approach to integrating these tools into clinical trials and clinical practice.

METHODS

Review article.

RESULTS

Endoscopy represents the criterion standard for the assessment of mucosal healing, and frequent endoscopic assessment is associated with a higher rate of achieving mucosal healing. The use of mucosal biopsy allows for the identification of persistent histologic disease activity, but the incremental clinical benefit of achieving histologic healing is yet to be determined. Magnetic resonance enterography has a high sensitivity for ulcer healing in endoscopically inaccessible disease activity. However, the presence of mucosal lesions cannot be reliably excluded based on this modality alone, and further small-bowel endoscopy should be considered in symptomatic patients. Video capsule endoscopy or device-assisted enteroscopy can be used, with device-assisted enteroscopy being preferred in stricturing Crohn's disease because of the risk of capsule retention or in patients in whom small-bowel malignancy is a possibility.

CONCLUSIONS

Endoscopy remains the criterion standard for the assessment of mucosal healing. Several alternative diagnostic modalities have become available that can be of value in specific clinical circumstances, particularly in patients with small-bowel involvement.

Advances in the Endoscopic Assessment of Inflammatory Bowel Diseases: Cooperation between Endoscopic and Pathologic Evaluations

Endoscopic assessment has a crucial role in the management of inflammatory bowel disease (IBD). It is particularly useful for the assessment of IBD disease extension, severity, and neoplasia surveillance. Recent advances in endoscopic imaging techniques have been revolutionized over the past decades, progressing from conventional white light endoscopy to novel endoscopic techniques using molecular probes or electronic filter technologies. These new technologies allow for visualization of the mucosa in detail and monitor for inflammation/dysplasia at the cellular or sub-cellular level. These techniques may enable us to alter the IBD surveillance paradigm from four quadrant random biopsy to targeted biopsy and diagnosis. High definition endoscopy and dye-based chromoendoscopy can improve the detection rate of dysplasia and evaluate inflammatory changes with better visualization. Dye-less chromoendoscopy, including narrow band imaging, iScan, and autofluorescence imaging can also enhance surveillance in comparison to white light endoscopy with optical or electronic filter technologies. Moreover, confocal laser endomicroscopy or endocytoscopy have can achieve real-time histology evaluation in vivo and have greater accuracy in comparison with histology. These new technologies could be combined with standard endoscopy or further histologic confirmation in patients with IBD. This review offers an evidence-based overview of new endoscopic techniques in patients with IBD.

Differential diagnosis in inflammatory bowel disease colitis: State of the art and future perspectives

Distinction between Crohn’s disease of the colon-rectum and ulcerative colitis or inflammatory bowel disease (IBD) type unclassified can be of pivotal importance for a tailored clinical management, as each entity often involves specific therapeutic strategies and prognosis. Nonetheless, no gold standard is available and the uncertainty of diagnosis may frequently lead to misclassification or repeated examinations. Hence, we have performed a literature search to address the problem of differential diagnosis in IBD colitis, revised current and emerging diagnostic tools and refined disease classification strategies. Nowadays, the differential diagnosis is an untangled issue, and the proper diagnosis cannot be reached in up to 10% of patients presenting with IBD colitis. This topic is receiving emerging attention, as medical therapies, surgical approaches and leading prognostic outcomes require more and more disease-specific strategies in IBD patients. The optimization of standard diagnostic approaches based on clinical features, biomarkers, radiology, endoscopy and histopathology appears to provide only marginal benefits. Conversely, emerging diagnostic techniques in the field of gastrointestinal endoscopy, molecular pathology, genetics, epigenetics, metabolomics and proteomics have already shown promising results. Novel advanced endoscopic imaging techniques and biomarkers can shed new light for the differential diagnosis of IBD, better reflecting diverse disease behaviors based on specific pathogenic pathways.

Advanced colonoscopic imaging using endocytoscopy

Optical biopsy techniques were recently introduced to luminal gastrointestinal endoscopy. These include confocal laser endomicroscopy, spectroscopic imaging techniques and endocytoscopy. Optical biopsy techniques allow on demand in vivo histology during ongoing endoscopy, thereby potentially accelerating clinical diagnosis and specific therapy. In the present review, we focus on endocytoscopy as one of the rapidly emerging optical biopsy techniques. We provide technical details of currently available endocytoscopy systems and give tips on their use in clinical practice. We also summarize applications of endocytoscopy for colorectal pathologies.

Colorectal cancer in inflammatory bowel disease: The risk, pathogenesis, prevention and diagnosis

Patients with inflammatory bowel disease (IBD) are at increased risk for developing colorectal cancer (CRC), although the overall incidence of IBD-associated CRC has been diminishing in recent decades in western countries. As demonstrated in previous studies, the risk of CRC in IBD increases with longer duration, extent of colitis, a familial history of CRC, coexistent primary sclerosing cholangitis, and the degree of inflammation. The pathogenesis of CRC in IBD is poorly understood. Similar to sporadic CRC, IBD-associated CRC is a consequence of sequential episodes of genomic alteration. Multiple inter-related pathways, including immune response by mucosal inflammatory mediators, oxidative stress, and intestinal microbiota, are also involved the pathogenesis of IBD-associated CRC. Continuing colonic inflammation appears to be a factor in the development of CRC; therefore, anti-inflammatory agents such as 5-aminosalicylate compounds and immune modulators have been considered as potential chemopreventive agents. Colonoscopic surveillance is widely accepted as being effective in reducing the risk of IBD-associated CRC, although no clear evidence has confirmed that surveillance colonoscopy prolongs survival in patients with extensive colitis. The traditional recommendation has been quadrantic random biopsies throughout the entire colon; however, several guidelines now have endorsed chromoendoscopy with a target biopsy because of increasing diagnostic yields and reduced workloads for endoscopists and pathologists. New technologies such as narrow band imaging, confocal endomicroscopy, and autofluorescence imaging have not yet been confirmed as surveillance strategies in IBD.

Endoscopic scoring systems for inflammatory bowel disease: pros and cons

Endoscopy plays a pivotal role for diagnosis and assessment of disease activity and extent in patients with inflammatory bowel diseases. International guidelines recommend the use of endoscopic scoring systems for evaluation of the prognosis and efficacy of medical treatments. Ideal scoring systems are easy to use, reproducible, reliable, responsive to changes, and validated in different clinical settings in order to guide therapeutic strategies. However, currently available endoscopic scoring systems often appear as complex for routine endoscopy and suffer from insufficient interobserver agreement and lack of formal validation which often limit their use in clinical trials. Here, we describe the role of endoscopic scoring systems in inflammatory bowel diseases focusing on pros and cons in the era of advanced endoscopic imaging and mucosal healing.

Advances in colonoscopy

Colonoscopy with polypectomy has been established as the major prevention and detection strategy for colorectal cancer for over a decade. Over this period advances in colonoscopic imaging, polyp detection, prediction of histopathology and polypectomy techniques have all been seen; however, the true magnitude of the limitations of colonoscopy has only recently been widely recognized. The rate and location of missed or interval cancers after complete colonoscopy appears to be influenced by the operator-dependency of colonoscopy and failure of conventional practices to detect and treat adenomatous, and possibly more importantly, non-adenomatous colorectal cancer precursors. Consequently, studies that expand our understanding of these factors and advances that aim to improve colonoscopy, polypectomy, and cancer protection are of critical importance.