Indications, stains and techniques in chromoendoscopy

Confocal laser endomicroscopy for gastric neoplasm

Confocal laser endomicroscopy (CLE) is a novel endoscopic modality that provides real-time histological information via high-resolution magnified view of the mucosa. CLE has a higher sensitivity, specificity, and diagnostic accuracy in detecting atrophic gastritis as compared to chromoendoscopy and narrow-band imaging. It can even predict low-grade and high-grade intraepithelial neoplasia by analyzing gastric pit patterns. CLE may have some advantages over the standard biopsy protocol, such as higher diagnostic yield and fewer biopsy requirements. Its diagnostic accuracy in detecting superficial gastric cancer is higher than that of white-light endoscopy. Inherent limitations, such as a narrow field of vision, can be surpassed by technological advancements and integration with other detection methods. Artificial intelligence holds promise in automated analysis of histopathological images. Thus, CLE can be helpful in screening for early gastric cancer and may help reduce the risk of complications from repeated biopsies, such as mucosal damage, bleeding, and infection.

Ultra-minimally invasive endoscopic techniques and colorectal diseases: Current status and its future

Colorectal diseases are increasing due to altered lifestyle, genetic, and environmental factors. Colonoscopy plays an important role in diagnosis. Advances in colonoscope (ultrathin scope, magnetic scope, capsule) and technological gadgets (Balloon assisted scope, third eye retroscope, NaviAid G-EYE, dye-based chromoendoscopy, virtual chromoendoscopy, narrow band imaging, i-SCAN, etc.) have made colonoscopy more comfortable and efficient. Now in-vivo microscopy can be performed using confocal laser endomicroscopy, optical coherence tomography, spectroscopy, etc. Besides developments in diagnostic colonoscopy, therapeutic colonoscopy has improved to manage lower gastrointestinal tract bleeding, obstruction, perforations, resection polyps, and early colorectal cancers. The introduction of combined endo-laparoscopic surgery and robotic endoscopic surgery has made these interventions feasible. The role of artificial intelligence in the diagnosis and management of colorectal diseases is also increasing day by day. Hence, this article is to review cutting-edge developments in endoscopic principles for the management of colorectal diseases.

Artificial intelligence-aided diagnostic imaging: A state-of-the-art technique in precancerous screening

BACKGROUND AND AIM

Chromoendoscopy with the use of indigo carmine (IC) dye is a crucial endoscopic technique to identify gastrointestinal neoplasms. However, its performance is limited by the endoscopist's skill, and no standards are available for lesion identification. Thus, we developed an artificial intelligence (AI) model to replace chromoendoscopy.

METHODS

This pilot study assessed the feasibility of our novel AI model in the conversion of white-light images (WLI) into virtual IC-dyed images based on a generative adversarial network. The predictions of our AI model were evaluated against the assessments of five endoscopic experts who were blinded to the purpose of this study with a staining quality rating from 1 (unacceptable) to 4 (excellent).

RESULTS

The AI model successfully transformed the WLI of polyps with different morphologies and different types of lesions in the gastrointestinal tract into virtual IC-dyed images. The quality ratings of the real IC-dyed and AI images did not significantly differ concerning surface structure (AI vs IC: 3.08 vs 3.00), lesion border (3.04 vs 2.98), and overall contrast (3.14 vs 3.02) from 10 sets of images (10 AI images and 10 real IC-dyed images). Although the score depended significantly on the evaluator, the staining methods (AI or real IC) and evaluators had no significant interaction (P > 0.05) with each other.

CONCLUSION

Our results demonstrated the feasibility of employing AI model's virtual IC staining, increasing the possibility of being employed in daily practice. This novel technology may facilitate gastrointestinal lesion identification in the future.

Image enhanced colonoscopy: updates and prospects-a review

Colonoscopy has been proven to be a successful approach in both identifying and preventing colorectal cancer. The incorporation of advanced imaging technologies, such as image-enhanced endoscopy (IEE), plays a vital role in real-time diagnosis. The advancements in endoscopic imaging technology have been continuous, from replacing fiber optics with charge-coupled devices to the introduction of chromoendoscopy in the 1970s. Recent technological advancements include "push-button" technologies like autofluorescence imaging (AFI), narrowed-spectrum endoscopy, and confocal laser endomicroscopy (CLE). Dye-based chromoendoscopy (DCE) is falling out of favor due to the longer time required for application and removal of the dye and the difficulty of identifying lesions in certain situations. Narrow band imaging (NBI) is a technology that filters the light used for illumination leading to improved contrast and better visibility of structures on the mucosal surface and has shown a consistently higher adenoma detection rate (ADR) compared to white light endoscopy. CLE has high sensitivity and specificity for polyp detection and characterization, and several classifications have been developed for accurate identification of normal, regenerative, and dysplastic epithelium. Other IEE technologies, such as blue laser imaging (BLI), linked-color imaging (LCI), i-SCAN, and AFI, have also shown promise in improving ADR and characterizing polyps. New technologies, such as Optivista, red dichromatic imaging (RDI), texture and color enhancement imaging (TXI), and computer-aided detection (CAD) using artificial intelligence (AI), are being developed to improve polyp detection and pathology prediction prior to widespread use in clinical practice.

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.

Comparison Trial between I-SCAN-Optical Enhancement and Chromoendoscopy for Evaluating the Horizontal Margins of Gastric Epithelial Neoplasms

Background/Aims

Endoscopic submucosal dissection is a widely used treatment for gastric epithelial neoplasms. Accurate delineation of the horizontal margins is necessary for the complete resection of gastric epithelial neoplasms. Recently, image-enhanced endoscopy has been used to evaluate horizontal margins of gastric epithelial neoplasms. The aim of this study was to investigate whether I-SCAN-optical enhancement (I-SCAN-OE) is superior to chromoendoscopy in evaluating the horizontal margin of gastric epithelial neoplasms.

Methods

This was a multicenter, prospective, and randomized trial. The participants were divided into two groups: I-SCAN-OE and chromoendoscopy. For both groups, we first evaluated the horizontal margins of early gastric cancer or high-grade dysplasia using white-light imaging, and then evaluated, the horizontal margins using I-SCAN-OE or chromoendoscopy. We devised a unique scoring method based on the pathological results obtained after endoscopic submucosal dissection to accurately evaluate the horizontal margins of gastric epithelial neoplasms. The delineation scores of both groups were compared, as were the ratios of positive/negative horizontal margins.

Results

In total, 124 patients were evaluated for gastric epithelial neoplasms, of whom 112 were enrolled in the study. A total of 112 patients participated in the study, and 56 were assigned to each group (1:1). There was no statistically significant difference in the delineation scores between the groups (chromoendoscopy, 7.80±1.94; I-SCAN-OE, 8.23±2.24; p=0.342).

Conclusions

I-SCAN-OE did not show superiority over chromoendoscopy in delineating horizontal margins of gastric epithelial neoplasms.

Recent advances in esophageal squamous cell precancerous conditions: A review

Esophageal squamous cell carcinoma (ESCC) is a common cancer in many developing countries in Asia and Africa, with a 5-year survival rate of approximately 20%. Most cases are diagnosed at an advanced age when there is no effective treatment strategy. Esophageal precancerous conditions have a much better prognosis, with a 5-year survival rate of over 90% by endoscopic diagnosis and treatment. Nevertheless, limitations, contraindications, and lymph node metastasis incompetency of endoscopy. Thus, the diagnosis and treatment of esophageal precancerous lesions remain a significant challenge. Biomarker investigations provide opportunities for target detection and therapy. Additionally, drug development is ongoing. Changes in lifestyle habits, such as diet balance, smoking and alcohol cessation, are beneficial for the prognosis of esophageal precancerous lesions. Collectively, multiple and sequential diagnoses and treatments are essential for curing esophageal precancerous lesions and reducing the incidence and mortality of ESCC.

Evolution and New Horizons of Endoscopy in Inflammatory Bowel Diseases

Endoscopy is the mainstay of inflammatory bowel disease (IBD) evaluation and the pillar of colorectal cancer surveillance. Endoscopic equipment, both hardware and software, are advancing at an incredible pace. Virtual chromoendoscopy is now widely available, allowing the detection of subtle inflammatory changes, thus reducing the gap between endoscopic and histologic assessment. The progress in the field of artificial intelligence (AI) has been remarkable, and numerous applications are now in an advanced stage of development. Computer-aided diagnosis (CAD) systems are likely to reshape most of the evaluations that are now prerogative of human endoscopists. Furthermore, sophisticated tools such as endocytoscopy and probe-based confocal laser endomicroscopy (pCLE) are enhancing our assessment of inflammation and dysplasia. Finally, pCLE combined with molecular labeling could pave the way to a new paradigm of personalized medicine. This review aims to summarize the main changes that occurred in the field of IBD endoscopy and to explore the most promising novelties.

Electronic chromo-endoscopy: technical details and a clinical perspective

Precise endoscopic assessment is necessary to detect neoplastic changes in an early stage. Electronic or virtual chromo-endoscopy (ECE) is an alternative to conventional dye-based chromo-endoscopy which markedly improves capillary pattern and hence can detect micro-vessel morphological changes of early neoplasia to target biopsies and aid in diagnosis. The clinical significance increased after the advent of endoscopic treatment modalities like ESD/EMR which requires precise delineation of extent and depth of lesion. Most of the studies have used narrow-band imaging (NBI) (Olympus Medical Systems Tokyo, Japan), although data from i-SCAN (PENTAX Endoscopy, Tokyo, Japan) and flexible spectral imaging color enhancement (FICE) (Fujinon, Fujifilm Medical Co, Saitama, Japan) are emerging. Electronic chromo-endoscopy is convenient compared to dye-based chromo-endoscopy in the sense that it is available at the push of a button in endoscope and reduces procedure time substantially with comparable efficacy. Scope of this review is to discuss available electronic chromo-endoscopy modalities and their role in the diagnosis, surveillance, and management of early GI neoplasia.

Activatable molecular probes for fluorescence-guided surgery, endoscopy and tissue biopsy

The real-time, dynamic optical visualization of lesions and margins ensures not only complete resection of the malignant tissues but also better preservation of the vital organs/tissues during surgical procedures. Most imaging probes with an "always-on" signal encounter high background noise due to their non-specific accumulation in normal tissues. By contrast, activatable molecular probes only "turn on" their signals upon reaction with the targeted biomolecules that are overexpressed in malignant cells, offering high target-to-background ratios with high specificity and sensitivity. This review summarizes the recent progress of activatable molecular probes in surgical imaging and diagnosis. The design principle and mechanism of activatable molecular probes are discussed, followed by specific emphasis on applications ranging from fluorescence-guided surgery to endoscopy and tissue biopsy. Finally, potential challenges and perspectives in the field of activatable molecular probe-enabled surgical imaging are discussed.

The evolution of endoscopic therapy for Barrett's esophagus

Barrett’s esophagus is the condition in which a metaplastic columnar epithelium replaces the stratified squamous epithelium that normally lines the distal esophagus. The condition develops as a consequence of chronic gastroesophageal reflux disease and predisposes the patient to the development of esophageal adenocarcinoma. The diagnosis and management of Barrett’s esophagus have undergone dramatic changes over the years and continue to evolve today. Endoscopic eradication therapy has revolutionized the management of dysplastic Barrett’s esophagus and early esophageal adenocarcinoma by significantly reducing the morbidity and mortality associated with the prior gold standard of therapy, esophagectomy. The purpose of this review is to highlight current principles in the management and endoscopic treatment of this disease.

Artificial intelligence in endoscopy: The challenges and future directions

Artificial intelligence based approaches, in particular deep learning, have achieved state-of-the-art performance in medical fields with increasing number of software systems being approved by both Europe and United States. This paper reviews their applications to early detection of oesophageal cancers with a focus on their advantages and pitfalls. The paper concludes with future recommendations towards the development of a real-time, clinical implementable, interpretable and robust diagnosis support systems.

Narrow-band imaging versus Lugol chromoendoscopy for esophageal squamous cell cancer screening in normal endoscopic practice: randomized controlled trial

BACKGROUND

Narrow-band imaging (NBI) is as sensitive as Lugol chromoendoscopy to detect esophageal squamous cell carcinoma (SCC) but its specificity, which appears higher than that of Lugol chromoendoscopy in expert centers, remains to be established in general practice. This study aimed to prove the superiority of NBI specificity over Lugol chromoendoscopy in the detection of esophageal SCC and high grade dysplasia (HGD) in current general practice (including tertiary care centers, local hospitals, and private clinics).

METHODS

This prospective randomized multicenter trial included consecutive patients with previous or current SCC of the upper aerodigestive tract who were scheduled for gastroscopy. Patients were randomly allocated to either the Lugol or NBI group. In the Lugol group, examination with white light and Lugol chromoendoscopy were successively performed. In the NBI group, NBI examination was performed after white-light endoscopy. We compared the diagnostic characteristics of NBI and Lugol chromoendoscopy in a per-patient analysis.

RESULTS

334 patients with history of SCC were included and analyzed (intention-to-treat) from 15 French institutions between March 2011 and December 2015. In per-patient analysis, sensitivity, specificity, positive and negative likelihood values were 100 %, 66.0 %, 21.2 %, and 100 %, respectively, for Lugol chromoendoscopy vs. 100 %, 79.9 %, 37.5 %, and 100 %, respectively, for NBI. Specificity was greater with NBI than with Lugol (P = 0.002).

CONCLUSIONS

As previously demonstrated in expert centers, NBI was more specific than Lugol in current gastroenterology practice for the detection of early SCC, but combined approaches with both NBI and Lugol could improve the detection of squamous neoplasia.

Endoscopic Advances for Gastric Neoplasia Detection

This article explores advances in endoscopic neoplasia detection with supporting clinical evidence and future aims. The ability to detect early gastric neoplastic lesions amenable to curative endoscopic submucosal dissection provides the opportunity to decrease gastric cancer mortality rates. Newer imaging techniques offer enhanced views of mucosal and microvascular structures and show promise in differentiating benign from malignant lesions and improving targeted biopsies. Conventional chromoendoscopy is well studied and validated. Narrow band imaging demonstrates superiority over magnified white light. Autofluorescence imaging, i-scan, flexible spectral imaging color enhancement, and bright image enhanced endoscopy show promise but insufficient evidence to change current clinical practice.

Gastric mucosal pathology in Belgian Shepherd dogs with and without clinical signs of gastric disease

BACKGROUND

Gastric carcinoma (GC) is uncommon in dogs, except in predisposed breeds such as Belgian Shepherd dogs (BSD) of the Tervuren and Groenendael varieties. When GC is diagnosed in dogs it is often late in the disease, resulting in a poorer prognosis. The aim of this prospective clinical study was to investigate possible associations of gastric mucosal pathologies with clinical signs, laboratory test results and GC in BSD. An online survey gathered epidemiological data to generate potential risk factors for vomiting as the predominant gastric clinical sign, and supported patient recruitment for endoscopy. Canine Chronic Enteropathy Clinical Activity Index (CCECAI) score and signs of gastroesophageal reflux (GER) were used to allocate BSD older than five years to either Group A, with signs of gastric disease, or Group B, without signs. Findings in the clinical history, laboratory tests and gastric histopathology of endoscopic biopsies were statistically analysed in search of associations.

RESULTS

The online survey included 232 responses. Logistic regression analysis recognized an association of vomiting with gagging, poor appetite and change in attitude. Recruitment for endoscopy included 16 BSD in Group A (mean age 9.1 ± 1.8 years, mean CCECAI = 3.1 ± 2.2 and signs of GER); and 11 in Group B (mean age 9.8 ± 1.4 years, CCECAI = 0, no signs of GER). Seven (25.9%) of the 27 BSD (Group A 4/16, Group B 3/11) had leukopenia. Serum C-reactive protein tended to be increased with more advanced GC (P = 0.063). Frequency of GC, mucosal atrophy, mucous metaplasia, or glandular dysplasia did not differ between groups. GC was frequently diagnosed (6/27), even without clinical signs (2/11). The odds ratio for vomiting (OR = 9.9; P = 0.016) was increased only when glandular dysplasia was present. GC was associated with mucous metaplasia (P = 0.024) and glandular dysplasia (P = 0.006), but not with mucosal atrophy (P = 1).

CONCLUSIONS

GC can develop as an occult disease, associated with metaplasia and dysplasia of the gastric mucosa. Suggestive clinical signs, notably vomiting, should warrant timely endoscopy in BSD. Extensive endoscopic screening of asymptomatic dogs remains, however, unrealistic. Therefore, biomarkers of mucosal pathology preceding clinical illness are needed to support an indication for endoscopy and enable early diagnosis of GC.

Thiolated Thermoresponsive Polymer Scaffolds with Tunable Mucoadhesivity for Intestinal Applications

Treatments for inflammatory bowel disease largely involve lifelong drug prescriptions or surgical intervention that can lead to poor quality of life for patients. Regenerative therapies involving stem cells have been shown to induce tissue regeneration but are limited in their efficacy by inefficient delivery mechanisms. Scaffold-based delivery of cells has been a key research focus of tissue engineers seeking to translate advances in stem cell research into clinical solutions. Biomaterial scaffolds that are delivered noninvasively to form in situ solid structures around the cells are preferable over surgically delivered monolithic scaffolds. We synthesized a novel biomaterial for in situ-forming, thermoresponsive intestinal scaffolds by thiolation of poly (N-isopropylacrylamide-co-glycidyl methacrylate) by conjugation of cysteine. Thiolation of the polymer enables chemical crosslinking with the intestinal mucus, enhancing mucoadhesion and permitting control of scaffold retention time in the intestinal environment. This study reports the synthesis and characterization of the thiolated polymer and investigates its crosslinking behavior, mucoadhesive properties, and cytocompatibility for potential tissue engineering applications in the intestine.

Fluorescence guided intraluminal endoscopy in the gastrointestinal tract: A systematic review

BACKGROUND

Conventional endoscopy is based on full spectrum white light. However, different studies have investigated the use of fluorescence based endoscopy systems where the white light has been supplemented by infrared light and the use of relevant fluorophores. Fluorescence endoscopy utilizes the fluorescence emitted from a fluorophore, visualizing what is not visible to the naked eye.

AIM

To explore the feasibility of fluorescence endoscopy and evaluate its use in diagnosing and evaluating gastrointestinal disease.

METHODS

We followed the PRISMA guidelines for this systematic review. The research covered five databases; PubMed, Scopus, Web of Science, Embase, and the Cochrane Collection, including only studies in English and Scandinavian languages. Authors screened title and abstract for inclusion, subsequently full-text for inclusion according to eligibility criteria listed in the protocol. The risk of bias was assessed for all studies according to the Newcastle-Ottawa Scale. The authors extracted the data and reported the results in both text and tables.

RESULTS

We included seven studies in the systematic review after screening a total of 2769 papers. The most prominent fluorophore was indocyanine green (n = 6), and whereas one study (n = 1) used Bevacizumab 800-CW. Three studies investigated fluorescence endoscopy in detecting varices, adenomas in patients with familial adenomatous polyposis and neoplasms in the gastrointestinal tract. Four studies evaluated the usefulness of fluorescence endoscopy in assessing tumor invasion. Three of the four studies reported an exceptional diagnostic accuracy (93%, 89% and 88%) in assessing tumor invasion, thus representing better visualization and more correct diagnosis by fluorescence endoscopy compared with the conventional endoscopy. The relationship between the endoscopic findings, tumor invasion, and tumor vascularity was evaluated in two studies showing a significant correlation (^dP < 0.05 and ^bP < 0.01).

CONCLUSION

The use of fluorescence endoscopy is a promising method adding diagnostic value in the detection of neoplasia, adenomas, and assessment of tumor invasion within the gastrointestinal tract. More studies are needed to utilize the feasibility of fluorescence endoscopy compared with other endoscopic methods.

Towards screening Barrett's oesophagus: current guidelines, imaging modalities and future developments

Barrett's oesophagus is the only known precursor to oesophageal adenocarcinoma (OAC). Although guidelines on the screening and surveillance exist in Barrett's oesophagus, the current strategies are inadequate. Oesophagogastroduodenoscopy (OGD) is the gold standard method in screening for Barrett's oesophagus. This invasive method is expensive with associated risks negating its use as a current screening tool for Barrett's oesophagus. This review explores current definitions, epidemiology, biomarkers, surveillance, and screening in Barrett's oesophagus. Imaging modalities applicable to this condition are discussed, in addition to future developments. There is an urgent need for an alternative non-invasive method of screening and/or surveillance which could be highly beneficial towards reducing waiting times, alleviating patient fears and reducing future costs in current healthcare services. Vibrational spectroscopy has been shown to be promising in categorising Barrett's oesophagus through to high-grade dysplasia (HGD) and OAC. These techniques need further validation through multicentre trials.

Uterine hemodynamic patterns, oxidative stress, and chromoendoscopy in mares with endometritis

This study aimed to evaluate the use of Doppler ultrasound for determining alterations in uterine thickness and uterine arteries, use of chromohysteroscopy in evaluating endometritis with biopsies, and the impact of endometritis on oxidative and hormonal status. Twenty Arabian mares were divided into control and endometritis groups. Each underwent a physical examination, Doppler ultrasound, chromoendoscopy, and uterine biopsy. Blood samples from each animal were collected for hematologic, hormonal, and oxidative analysis. Results revealed a significant increase in estradiol, malondialdehyde (MDA), and nitric oxide metabolites (NOMs) associated with a significant decrease in progesterone and total antioxidant capacity (TAC) in the endometritis group. There was a significant difference in uterine thickness in the endometritis group. Uterine blood flow analyzed by color mode showed a significant increase in the endometritis group, while the spectral mode showed a significant increase in Doppler velocities and blood flow rate accompanied by a significant decrease in Doppler indices. The endometritis group showed ridged, bluish color in the endometrial wall, indicating hyperemia. Biopsy showed mononuclear inflammatory cells and edema in the endometrial interstitial tissue with sloughing of the epithelial lining. Conclusion: Endometritis in mares is associated with oxidative processes and presents with an increase in MDA and NOMs and a decrease in TAC. Doppler ultrasound improved endometritis diagnosis because it showed alterations in uterine vascularization. Chromoendoscopy improved the accuracy in taking biopsy samples because it allows the practitioner to select appropriate areas for biopsy to improve histopathological diagnostic outcomes. Therefore, this technique is worthy of further study in the field of veterinary equine reproduction.

Novel treatment for gastric intestinal metaplasia, a precursor to cancer

BACKGROUND AND AIM

Gastric intestinal metaplasia (GIM) is precancerous with a worldwide prevalence of 25%. Eradicating Helicobacter pylori prevented about half of gastric cancers; failure to prevent the rest was attributed to GIM. GIM is irreversible and often extensive. There is no treatment. Existing endoscopic mucosal resection (EMR) is designed to treat early gastric cancer of usually <2 cm. We designed a two-endoscope technique of EMR for extensive lesions such as GIM.

METHODS

Forty patients with histologically confirmed moderate to severe GIM (operative link on GIM [OLGIM] classification) received the treatment in a daycare center. Chromoendoscopy with methylene blue was first performed to indicate the GIM. Submucosal saline injections were used to lift the stained mucosa to form multiple safety cushions, which were transformed into artificial polyps by suction and ligation, using a cap familiar to gastroenterologists for ligation of esophageal varices. EMRs were then achieved by snare polypectomy. By rotating two gastroscopes, one was designated to perform lift and snare and the other to perform suction and ligation; cycles of lift-ligate-snare were performed until all stained mucosa was removed. Assessment chromoendoscopy with ≥seven biopsies was performed at 6 months.

RESULTS

A total of 227 EMRs were performed, with a median of 3.5 per patient. Bleeding was uncommon and minimal. Gastric perforation ascribable to loss of a safety cushion occurred in one patient. Chromoendoscopy at 6 months in 36 willing patients showed no recurrence of GIM.

CONCLUSION

The two-endoscope technique of EMR for GIM was essentially safe and effective, with no recurrence at 6 months. It could be performed by endoscopists with standard skills.

Dye-based chromoendoscopy following polypectomy reduces incomplete polyp resection

Background and study aims  The completeness of a polyp resection is an important determinant of quality in colonoscopy, and may reduce incidence of interval cancers. Incomplete resection rates (IRR) vary widely and range from 6.5 % to 22.7 %. Residual disease is more likely with larger polyps, for sessile serrated adenomas, and with more proximal lesions. Chromoendoscopy is increasingly employed in lesion detection. The aims of this study were to assess local IRR, and to determine whether chromoendoscopy could correctly identify residual disease post polypectomy. Patients and methods  This was a prospective study examining post polypectomy sites. Chromoendoscopy (0.13 % indigo carmine) was applied to resection bases to identify residual disease. Targeted base biopsies were taken from identified residual disease (positive group) or random base biopsies were taken when a clear base was visualised (negative group). Overall rates of incomplete resection were documented. Reported rates post chromoendoscopy and actual histological rates were documented and compared. Results  A total of 102 polyps were identified for inclusion, of which 15 % (n = 16) were excluded. Resection quality was evaluated in 86 polyps of 61 patients (female n = 33 54 %; mean Age 62.3 years). Polyps were mainly removed by cold snare (n = 71, 82.5 %). Most polyps (n = 58, 67 %) measured between 5 to 10 mm. Polyps were largely located in the right colon (n = 57, 66 %). Overall histological residual disease occurred in 17 /86 (19.6 %). Chromoendoscopy correctly identified residual disease in 13 of 17 bases (76.5 %). Only four of /86 (4.6 %) of polyp bases were missclassified post-chromoendoscopy (odds ratio 0.284 (95 % CI 0.0857-0.9409), P  = 0.03). Conclusion  Indigo carmine chromoendoscopy improves early detection of residual disease post polypectomy, reducing incomplete resection rates.

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.

Early Esophageal Cancer: A Gastroenterologist's Disease

Traditionally, early esophageal cancer (i.e., cancer limited to the mucosa or superficial submucosa) was managed surgically; the gastroenterologist's role was primarily to diagnose the tumor. Over the last decade, advances in endoscopic imaging, ablation, and resection techniques have resulted in a paradigm shift-diagnosis, staging, treatment, and surveillance are within the endoscopist's domain. Yet, there are few reviews that provide a focused, evidence-based approach to early esophageal cancer, and highlight areas of controversy for practicing gastroenterologists. In this manuscript, we will discuss the following: (1) utility of novel endoscopic technologies to identify high-grade dysplasia and early esophageal cancer, (2) role of endoscopic resection and imaging to stage early esophageal cancer, (3) endoscopic therapies for early esophageal cancer, and (4) indications for surgical and multidisciplinary management.

Evaluation and Management of Premalignant Conditions of the Esophagus: A Systematic Survey of International Guidelines

Esophageal cancer represents one of the most lethal forms of malignancy. The growing incidence of esophageal adenocarcinoma represents an emerging public health concern. This review article summarizes current diagnostic, management, and therapeutic practices of premalignant conditions of the esophagus including Barrett's esophagus, tylosis, granular cell tumors, achalasia, and the ingestion of caustic substances. Our report provides clinicians and academics with a global clinical perspective regarding presentation, surveillance guidelines, and therapeutic management of these esophageal conditions.

A roadmap for the clinical implementation of optical-imaging biomarkers

Clinical workflows for the non-invasive detection and characterization of disease states could benefit from optical-imaging biomarkers. In this Perspective, we discuss opportunities and challenges towards the clinical implementation of optical-imaging biomarkers for the early detection of cancer by analysing two case studies: the assessment of skin lesions in primary care, and the surveillance of patients with Barrett's oesophagus in specialist care. We stress the importance of technical and biological validations and clinical-utility assessments, and the need to address implementation bottlenecks. In addition, we define a translational roadmap for the widespread clinical implementation of optical-imaging technologies.

Advanced endoscopic methods in gastrointestinal diseases: a systematic review

Endoscopic imaging is the main method for detecting gastrointestinal diseases, which adversely affect human health. White light endoscopy (WLE) was the first method used for endoscopic examination and is still the preliminary step in the detection of gastrointestinal diseases during clinical examination. However, it cannot accurately diagnose gastrointestinal diseases owing to its poor correlation with histopathological diagnosis. In recent years, many advanced endoscopic methods have emerged to improve the detection accuracy by endoscopy. Chromoendoscopy (CE) enhances the contrast between normal and diseased tissues using biocompatible dye agents. Narrow band imaging (NBI) can improve the contrast between capillaries and submucosal vessels by changing the light source acting on the tissue using special filters to realize the visualization of the vascular structure. Flexible spectral imaging color enhancement (FICE) technique uses the reflectance spectrum estimation technique to obtain individual spectral images and reconstructs an enhanced image of the mucosal surface using three selected spectral images. The i-Scan technology takes advantage of the different reflective properties of normal and diseased tissues to obtain images, and enhances image contrast through post-processing algorithms. These abovementioned methods can be used to detect gastrointestinal diseases by observing the macroscopic structure of the digestive tract mucosa, but the ability of early cancer detection is limited with low resolution. However, based on the principle of confocal imaging, probe-based confocal laser endomicroscopy (pCLE) can enable cellular visualization with high-performance probes, which can present cellular morphology that is highly consistent with that shown by biopsy to provide the possibility of early detection of cancer. Other endoscopic imaging techniques including endoscopic optical coherence tomography (EOCT) and photoacoustic endoscopy (PAE), are also promising for diagnosing gastrointestinal diseases. This review focuses on these technologies and aims to provide an overview of different technologies and their clinical applicability.

CHROMOENDOSCOPY USING TOLUIDINE BLUE PLUS LUGOL'S SOLUTION FOR EARLY DIAGNOSIS OF ESOPHAGEAL PREMALIGNANT LESIONS AND SUPERFICIAL NEOPLASMS IN HIGH-RISK PATIENTS

BACKGROUND

Esophageal cancer is the eighth most common cancer. The prognosis is bleak in patients with advanced stages. Patients with early disease have a better prognosis than those with advanced stage. There are several techniques for the screening of premalignant and superficial lesions including chromoendoscopy.

OBJECTIVE

This article aimed to determine the effectiveness of chromoendoscopy with toluidine blue combined with Lugol's solution for diagnosis of esophageal premalignant and superficial neoplastic lesions in high risk patients.

METHODS

Routine white light upper endoscopy was performed. Toluidine blue was sprayed from the gastroesophageal junction to 20 cm of the dental arch. Then the uptake dye areas were characterized. Later Lugol's solution was sprayed. Areas with less-intense staining were characterized. Biopsy of the toluidine blue capturing areas and areas with less-intense staining of Lugol's solution were taken. In the cases where lesions were not evidenced after application of dyes, biopsies four quadrants of the esophageal mucosa were taken. The samples were evaluated by a digestive pathologist.

RESULTS

Barrett's esophagus was the most common premalignant lesion and the early neoplastic lesion was adenocarcinoma with a sensitivity of 100%, specificity 85.7%, positive predictive value 30%, negative predictive value 100%, positive likelihood ratio 7 negative likelihood ratio 0.

CONCLUSION

Chromoendoscopy with toluidine blue combined with Lugol's solution is a useful tool in the screening of esophageal premalignant lesions and superficial neoplasms.

Attenuated total reflection Fourier-transform infrared spectral discrimination in human bodily fluids of oesophageal transformation to adenocarcinoma

Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) of biofluids was used to detect oesophageal stages through to oesophageal adenocarcinoma.

Advanced Imaging for Barrett's Esophagus and Early Neoplasia: Surface and Subsurface Imaging for Diagnosis and Management

PURPOSE OF REVIEW

Esophageal adenocarcinoma bears one of the fastest rising incidence of any cancers and generally arises in the setting of gastroesophageal reflux and Barrett's esophagus. However, early detection of neoplasia can be challenging since most patients are asymptomatic until they progress to more advanced and less curable stages, and early dysplastic lesions can be small, multifocal, and difficult to detect. Clearly, new imaging tools are needed in light of sampling error associated with random biopsies, the current standard of practice.

RECENT FINDINGS

Advances in endoscopic imaging including virtual chromoendoscopy, confocal laser endomicroscopy, and subsurface imaging with optical coherence tomography have ushered in a new era for detecting subtle neoplastic lesions. Moreover, in light of esophagus-sparing treatments for neoplastic lesions, such tools are likely to guide ablation and follow-up management. While there is no ideal single imaging modality to facilitate improved detection, staging, ablation, and follow-up of patients with dysplastic Barrett's esophagus, new advances in available technology, the potential for multimodal imaging, and the use of computer-aided diagnosis and biomarkers all hold great promise for improving detection and treatment.

Evaluation of chromocystoscopy in the diagnosis of cystitis in female donkeys

Early detection of cystitis in equine is essential to improve the prognosis and outcome of therapy. However, the conventional white light endoscopy is not sufficiently accurate for this purpose. Hence, this study evaluated chromoendoscopy as a recent diagnostic tool for cystitis in female donkeys. For this purpose, 5 apparently normal donkeys (control group) and 5 female donkeys with cystitis (diseased group) were used. Physical and rectal examinations, urine analysis, white light cystoscopy, methylene blue-based chromoendoscopy and histopathology were performed in all animals. Turbid urine exhibiting an alkaline pH and a significant (P = .02) increase in the numbers of RBCs and WBCs was observed in the diseased group compared to the control one. In the control group, white light cystoscopy showed a smooth pale pink glistening mucosa with two openings of the ureters and visible submucosal blood vessels. During chromocystoscopy, faint bluish discoloration of the mucosal surface with clearly visible submucosal blood vessels was detectable. These findings were correlated with the histopathological findings of the biopsies collected from the urinary bladder. In the diseased group, white-light cystoscopy showed clearly visible blood vessels, mildly hyperaemic mucosa in focal or diffuse forms and small vesicle formation. Chromocystoscopy revealed dark bluish oedematous and irregular mucosa either in a focal form or a diffuse form (marbled appearance) with deeply stained submucosal blood vessels. Histopathologically, the urothelium was hyperplastic with squamous metaplasia and the lamina propria was infiltrated with few leukocytes and congested blood vessels. Small bluish dots representing the absorbed methylene blue dye were seen in the inflamed areas against the lightly stained mucosa of the bladder. Severe diffuse necrotic cystitis was also seen with bacterial aggregations on the surface. Gram's staining revealed both gram positive bacilli and Gram positive coccobacilli. In conclusion, chromoendoscopy is a helpful tool for early diagnosis of cystitis in female donkeys and enables targeted biopsies, which improves the prognosis and outcome of therapy.

Targeted Optical Imaging Agents in Cancer: Focus on Clinical Applications

Molecular imaging is an emerging strategy for in vivo visualization of cancer over time based on biological mechanisms of disease activity. Optical imaging methods offer a number of advantages for real-time cancer detection, particularly in the epithelium of hollow organs and ducts, by using a broad spectral range of light that spans from visible to near-infrared. Targeted ligands are being developed for improved molecular specificity. These platforms include small molecule, peptide, affibody, activatable probes, lectin, and antibody. Fluorescence labeling is used to provide high image contrast. This emerging methodology is clinically useful for early cancer detection by identifying and localizing suspicious lesions that may not otherwise be seen and serves as a guide for tissue biopsy and surgical resection. Visualizing molecular expression patterns may also be useful to determine the best choice of therapy and to monitor efficacy. A number of these imaging agents are overcoming key challenges for clinical translation and are being validated in vivo for a wide range of human cancers.

DNA damage response genes mark the early transition from colitis to neoplasia in colitis-associated colon cancer

Chronic intestinal inflammation predisposes patients with Inflammatory Bowel Disease (IBD) to Colitis-Associated Cancer (CAC). In the setting of chronic inflammation, microsatellite instability (MSI) results from early loss of DNA damage response (DDR) genes, ultimately leading to tumor formation. Despite continued efforts to improve early detection of high risk, pre-dysplastic regions in IBD patients, current macroscopic and genetic surveillance modalities remain limited. Therefore, understanding the regulation of key DDR genes in the progression from colitis to cancer may improve molecular surveillance of CAC. To evaluate DDR gene regulation in the transition from colitis to tumorigenesis, we utilized the well-established Azoxymethane/Dextran Sodium Sulfate (AOM/DSS) pre-clinical murine model of CAC in C57BL/6 mice. In order to assess colonic tumor burden in the setting of mutagen and intestinal irritation, tumors were visualized and graded in real time through high-resolution murine colonoscopy. Upon sacrifice, colons were opened and assessed for macroscopic tumor via high magnification surgical lenses (HMSL). Tissues were then sectioned and separated into groups based on the presence or absence of macroscopically visible tumor. Critical DDR genes were evaluated by semi-quantitative RT-PCR. Interestingly, colon tissue with macroscopically visible tumor (MVT) and colon tissue prior to observable tumor (the non-macroscopically visible tumor-developing group, NMVT) were identical in reduced mRNA expression of mlh1, anapc1, and ercc4 relative to colitic mice without mutagen, or those receiving mutagen alone. Colitis alone was sufficient to reduce colonic ercc4 expression when compared to NMVT mice. Therefore, reduced ercc4 expression may mark the early transition to CAC in a pre-clinical model, with expression reduced prior to the onset of observable tumor. Moreover, the expression of select DDR genes inversely correlated with chronicity of inflammatory disease. These data suggest ercc4 expression may define early stages in the progression to CAC.

Chromoendoscopy Plus Mucosal Resection Versus Conventional Electrocoagulation for Intestinal Polyps in Children: Two Case Series

BACKGROUND

Conventional high-frequency electrocoagulation (HFEC) of intestinal polyps may be difficult in children and endoscopic mucosal resection (EMR) could be a less invasive option. Chromoendoscopy improves tissue localization during endoscopy, but its exact influence on the outcomes of children with intestinal lesions is still unknown.

AIMS

To analyze a series of children treated with EMR or HFEC and assess the value of chromoendoscopy.

METHODS

This was a retrospective analysis of two case series of patients treated at the Gastroenterology Department of the Guiyang Children's Hospital between February 2014 and November 2016. The children underwent EMR (n = 34) or conventional HFEC (n = 120). Demographic, clinical, and perioperative data were analyzed.

RESULTS

The polyps were larger in the HFEC group [median, 3.9 (0.1-27.0) versus 1.3 (0.03-64.0) mm, P = .03]. There was a higher frequency of multiple polyps in the EMR group (50.0% versus 15.1%, P < .001). Operation time and intraoperative bleeding were similar between the two groups (both P > .05). Hospital stay was longer with EMR than with HFEC [median, 5 (3-12) versus 4 (2-14) days, P = .02]. There was no intestinal perforation in either group. Postoperative bleeding amount was similar in both groups (P = .73). In the EMR group, 19 patients were operated using chromoendoscopy, whereas only 2 patients in the HFEC group were operated.

CONCLUSION

EMR could be appropriate for the treatment of intestinal polyps in children.

Canine breeds associated with gastric carcinoma, metaplasia and dysplasia diagnosed by histopathology of endoscopic biopsy samples

Background

Gastric carcinoma (GC) is a rather rare pathological finding in dogs, with the exception of some breeds which seem predisposed. The etiopathogenesis is largely unknown in dogs, whereas in humans GC often develops from gastric mucosal metaplasia and dysplasia. This study investigates whether dogs of certain breeds are more often subject to gastroduodenoscopy (GDS), and diagnosed with GC, mucosal metaplasia or dysplasia. A retrospective clinical database search was performed at the Veterinary Teaching Hospital at the University of Helsinki, Finland. The following inclusion criteria were applied to estimate relative risk for metaplasia/dysplasia and GC: dogs from pure breeds with at least five individuals subject to GDS with histopathology of gastric biopsies.

Results

Between 2006 and 2016, from a total of 54945 canine patients presented, 423 dogs underwent GDS. Inclusion criteria were met in 180 dogs of 20 different pure breeds. Eight dogs had GCs (mean age = 9.8 ± 1.7 years): Belgian Tervuren (n = 4), Collie (n = 2), Golden Retriever (n = 1) and Jack Russel Terrier (n = 1). Fourteen dogs of eight breeds had gastric mucosal metaplasia or dysplasia. A log-binomial statistical model revealed that dogs in the following breeds had a significantly higher probability to undergo GDS than the others in the study population: Australian Terrier, Belgian Tervuren, Cairn Terrier, Collie and Siberian Husky. Belgian Tervuren was found at higher risk to be diagnosed with GC [RR = 19 (5.7–63.9; P < 0.0001)], as well as mucosal metaplasia/dysplasia [RR (7.6; 2.95–19.58; P < 0.0001)], as compared to the other breeds included. Shetland Sheepdog had an increased RR (5.83; 1.75–19.45; P = 0.0041) for metaplasia.

Conclusions

The results indicate a very low incidence of GC in dogs. The Belgian Tervuren, however, appears as predisposed. The histopathologic descriptions of mucosal changes such as metaplasia and dysplasia were also rare, but were more frequent in the Belgian Tervuren. Previous reports of these changes in dogs are very scarce, but they might be presumably related to GC in dogs, as they are in humans. Future research should investigate the possible role of metaplasia and dysplasia in the development of GC in dogs, especially those of predisposed breeds.

Fluorescence contrast-enhanced proliferative lesion imaging by enema administration of indocyanine green in a rat model of colon carcinogenesis

The fluorescent contrast agent indocyanine green (ICG) is approved by the Food and Drug Administration for clinical applications. We previously reported that cultured human colon tumor cells preferentially take up ICG by endocytic activity in association with disruption of their tight junctions. The present study explored ICG availability in fluorescence imaging of the colon to identify proliferative lesions during colonoscopy. The cellular uptake of ICG in cultured rat colon tumor cells was examined using live-cell imaging. Colon lesions in rats administered an ICG-containing enema were further assessed in rats with azoxymethane-induced colon carcinogenesis, using in vivo endoscopy, ex vivo microscopy, and immunofluorescence microscopy. The uptake of ICG by the cultured cells was temperature-dependent. The intracellular retention of the dye in the membrane trafficking system suggested endocytosis as the uptake mechanism. ICG administered via enema accumulated in colon proliferative lesions ranging from tiny aberrant crypt foci to adenomas and localized in proliferating cells. Fluorescence endoscopy detected these ICG-positive colonic proliferative lesions in vivo. The immunoreactivity of the tight-junction molecule occludin was altered in the proliferative lesions, suggesting the disruption of the integrity of tight junctions. These results suggest that fluorescence contrast-enhanced imaging following the administration of an ICG-containing enema can enhance the detection of mucosal proliferative lesions of the colon during colonoscopy. The tissue preference of ICG in the rat model evaluated in this study can be attributed to the disruption of tight junctions, which in turn promotes endocytosis by proliferative cells and the cellular uptake of ICG.

New Strategies to Improve Polypectomy During Colonoscopy

In the United States, colorectal cancer (CRC) is the second-leading cause of cancer-related deaths. The most effective strategy for prevention of CRC is to screen for and remove precancerous polyps. There are various ways to screen for CRC. In the United States, the most common method is colonoscopy. Polyps are classified primarily through pathology. Size is the primary risk factor for malignancy. In general, the bigger the polyp, the greater the risk for malignancy. There are 3 basic options for removal: standard polypectomy; advanced resection techniques, known as endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD); and surgical removal. In the past 10 years, the use of surgical removal has significantly decreased. Noninvasive, nonmalignant polyps can be removed endoscopically. EMR and ESD are very effective and achieve similar clinical outcomes. Both procedures begin with a submucosal injection. The submucosal lift is one of the most significant advances that have been made in polypectomy. Traditionally, the approach to achieving a submucosal lift has relied on the use of a saline solution. Saline is inexpensive and widely available, but it dissipates quickly. Various viscous agents have been added to saline to maintain mucosal lifting throughout the procedure. Although most are effective, they are used off-label. The only solution approved by the US Food and Drug Administration for the submucosal lift procedure is Eleview. In a clinical trial, Eleview decreased the mean total injected volume and the mean total injected volume per lesion as compared with saline. Other advances in polypectomy techniques include the use of cold snare polypectomy and high-definition colonoscopes. The quality of the colonoscopy can also be improved if a physician knows and monitors his or her adenoma detection rate.

Endoscopic Management of Early Gastric Adenocarcinoma and Preinvasive Gastric Lesions

Early gastric cancer (ECG) can be difficult to diagnose endoscopically. Endoscopists should be familiar with subtle changes and endoscopic features of EGC. Chromoendoscopy and image-enhanced endoscopy improve diagnostic accuracy and facilitate endoscopic resection. Endoscopic submucosal dissection is a preferred endoscopic technique for resection of EGC and offers a comparable overall survival to surgical resection. Endoscopic management of benign gastric epithelial polyps (fundic gland polyps, hyperplastic polyps, and gastric adenoma) depends on patient symptomatology, patient's comorbidities (eg, familial syndromes), lesions' characteristics, and risk of malignant transformation. This article provides an overview of endoscopic management of EGC and common premalignant gastric lesions.

Fluorescein as a topical fluorescent contrast agent for quantitative microendoscopic inspection of colorectal epithelium

Fiber bundle microendoscopic imaging of colorectal tissue has shown promising results, for both qualitative and quantitative analysis. A quantitative image quality control and image feature extraction algorithm was previously designed for quantitative image feature analysis of proflavine-stained ex vivo colorectal tissue. We investigated fluorescein as an alternative topical stain. Images of ex vivo porcine, caprine, and human colorectal tissue were used to compare microendoscopic images of tissue topically stained with fluorescein and proflavine solutions. Fluorescein was shown to be comparable for automated crypt detection, with an average crypt detection sensitivity exceeding 90% using a combination of three contrast limit pairs.

Advanced imaging in colonoscopy: contemporary approach to dysplasia surveillance in inflammatory bowel disease

Inflammatory bowel disease (IBD) (ulcerative colitis (UC) and Crohn's disease (CD)) is a chronic relapsing/remitting condition characterised by intestinal inflammation. One of the main concerns in patients with longstanding ulcerative and Crohn's colitis is development of colonic dysplasia and colorectal cancer (CRC), a risk higher than that of the general population. Colonoscopy surveillance programmes have been developed by major societies worldwide to improve early dysplasia detection and treatment, thus preventing progression to colorectal cancer. Colonoscopy is an imperfect tool as lesions can be missed, an issue even more relevant to colitic patients, where mucosal inspection and lesion recognition may prove challenging. Extensive research has been undertaken on performance improvement in this area while technical advances in optical imaging, such as high-definition, have made their way into modern endoscopy units. Techniques and technologies available to enhance optical diagnosis of dysplasia in inflammatory bowel disease are reviewed in this paper, focusing on those that are realistic, widely available and feasible for everyday practice.

Meta-analysis: The diagnostic efficacy of chromoendoscopy for early gastric cancer and premalignant gastric lesions

BACKGROUND AND AIM

Chromoendoscopy (CE) is widely used in the diagnosis of early gastric cancer (EGC) and premalignant gastric lesions (PGLs). We conducted a meta-analysis to evaluate the diagnostic efficacy of CE for EGC and PGLs.

METHODS

We searched PubMed/MEDLINE, EMBASE, and the Cochrane library to identify all eligible studies according to inclusion and exclusion standards. Publication bias was tested using Funnel plots and Egger's test. The possible sources of the heterogeneity were explored by performing a meta-regression analysis. Heterogeneity was assessed by the Q test and I(2) statistic.

RESULTS

Ten studies met the inclusion standards, including a total of 699 patients and 902 lesions. The pooled sensitivity, specificity, and area under the curve of CE were 0.90 (95% confidence interval, 0.87-0.92), 0.82 (95% confidence interval, 0.79-0.86), and 0.9464, respectively. In subgroup analysis of diagnostic accuracy, CE showed higher accuracy versus standard white light endoscopy for EGC (P = 0.005) and PGLs (P = 0.001).

CONCLUSION

Chromoendoscopy seems to have a high diagnostic efficacy and improve the detection of EGC and PGLs compared with standard white light endoscopy.

Usefulness of virtual chromoendoscopy in the evaluation of subtle small bowel ulcerative lesions by endoscopists with no experience in videocapsule

BACKGROUND AND STUDY AIMS

In videocapsule endoscopy examination (VCE), subtle variations in mucosal hue or pattern such as those seen in ulcerations can be difficult to detect, depending on the experience of the reader. Our aim was to test whether virtual chromoendoscopy (VC) techniques, designed to enhance the contrast between the lesion and the normal mucosa, could improve the characterization of ulcerative mucosal lesions.

PATIENTS AND METHODS

Fifteen trainees or young gastroenterologists with no experience in VCE were randomly assigned to evaluate 250 true ulcerative and 100 false ulcerative, difficult-to-interpret small bowel lesions, initially as white light images (WLI) and then, in a second round, with the addition of one VC setting or again as WLI, labeling them as real lesions or artifacts.

RESULTS

On the overall image evaluation, an improvement in lesion characterization was observed by adding any chromoendoscopy setting, especially Blue mode and FICE 1, with increases in accuracy of 13 % [95 %CI 0.8, 25.3] and 7.1 % [95 %CI - 17.0, 31.3], respectively. However, when only false ulcerative images were considered, with the same presets (Blue mode and FICE 1), there was a loss in accuracy of 10.7 % [95 %CI - 10.9, 32.3] and 7.3 % [95 %CI - 1.3, 16.0], respectively. The interobserver agreement was poor for both readings.

CONCLUSIONS

VC helps beginner VCE readers correctly categorize difficult-to-interpret small bowel mucosal ulcerative lesions. However, false lesions tend to be misinterpreted as true ulcerative with the same presets. Therefore care is advised in using VC especially under poor bowel preparation.

Optical diagnosis of colorectal neoplasia: A Western perspective

Optical diagnosis is an emerging paradigm in Western endoscopic practice for the colonoscopic management of diminutive polyps, and includes two complementary clinical strategies: 'resect and discard', in which diminutive high-confidence adenomas are identified, and then removed and discarded without pathological assessment; and 'diagnose and leave', where diminutive high-confidence hyperplastic polyps are identified in the rectosigmoid and then left without resection or biopsy. Like other aspects of colonoscopy performance, adoption of optical diagnosis in Western practice is limited by operator dependency and variation in clinical effectiveness. There is substantial potential for optical diagnosis of colorectal neoplasia during colonoscopy to alleviate the rising costs of health care in the West. However, operator dependence in diagnostic performance together with critical system factors such as informed consent, credentialing, medical legal support and reimbursement incentives must be overcome before optical diagnosis of diminutive lesions is considered for widespread adoption in Western clinical practice.

[Usefulness of systematic chromoendoscopy with a double dye staining technique for the detection of dysplasia in patients with premalignant gastric lesions]

INTRODUCTION

Premalignant gastric lesions have an increased risk to develop gastric cancer.

OBJECTIVE

To evaluate the usefulness of systematic endoscopy that includes chromoendoscopy with a double dye staining technique for the detection of dysplasia in patients with premalignant gastric lesions.

PATIENTS AND METHODS

This longitudinal, prospective study was performed in patients with gastric atrophy, intestinal metaplasia or dysplasia who were referred for endoscopy less than 6 months after the initial diagnosis. The second endoscopy was performed in three phases: phase 1, exhaustive and systematic review of the mucosa with photographic documentation and biopsies of suspicious areas; phase 2, chromoendoscopy with a double dye staining technique using acetic acid 1.2% and indigo carmine 0.5%; phase 3, topographic mapping and random biopsies.

RESULTS

A total of 50 patients were included. Nine (18%) had atrophic gastritis, 38 (76%) had intestinal metaplasia, and 3 (6%) had low-grade dysplasia. Systematic endoscopy with chromoendoscopy using a double dye staining technique detected more patients with dysplasia (9 versus 3, p<.05), and a larger number of biopsies with the diagnosis of dysplasia were obtained. This occurred for visible (6 vs. 0, p<.05) and non-visible lesions (6 vs. 3, p=NS). In one patient, initial low-grade dysplasia was not detected again in the systematic endoscopy, giving a global endoscopic performance for the detection of lesions of 92%.

CONCLUSIONS

Patients with premalignant gastric lesions have synchronous lesions with greater histological severity, which are detected when systematic endoscopy is conducted with indigo carmine dye added to acetic acid.

Advanced Imaging in Barrett's Esophagus

Barrett's esophagus (BE) is present in up to 5.6% of the US population and is the precursor lesion for esophageal adenocarcinoma. Surveillance endoscopy is the primary management approach for BE. However, standard protocol biopsies have been associated with significant miss rates of dysplastic lesions in patients with BE. Thus, a variety of methods to optimize the imaging of BE have been developed to improve the efficiency and diagnostic yield of surveillance endoscopy in detecting early neoplasia. These techniques use changes that occur at macroscopic, microscopic, and subcellular levels in early neoplasia and are the focus of this article.

Dual optical modality endoscopic imaging of cancer development in the mouse colon

BACKGROUND AND OBJECTIVE

We utilize a miniature, dual-modality endoscope that combines fluorescence-based surface magnifying chromoendoscopy (SMC) and optical coherence tomography (OCT) to follow the anatomical changes that occur during adenoma development in the mouse colon.

MATERIALS AND METHODS

Twenty-five mice were treated with the carcinogen azoxymethane (AOM) to induce tumor development in the distal colon, or were treated with saline as control, and were imaged over six months. OCT detects adenoma number with high sensitivity and specificity and can measure lesion size. In methylene blue-lavaged colons, SMC detects changes in the colonic crypts. SMC images of control mouse colons exhibit reticulated patterns of crypts of equal size, forming either a dot or honeycomb pattern.

RESULTS

Images of AOM-treated colons show mild crypt irregularities even in grossly normal tissue. Images of small to medium adenoma exhibit larger crypts, more intense signal, and irregular spacing whereas those of large adenoma have heterogeneous, intense signal and loss of crypt structure.

CONCLUSIONS

The combination of OCT and SMC permits the detection of neoplastic events from the earliest stages of crypt irregularities before gross tissue changes are noted, through to measuring the growth of protruding adenoma.

Endoscopic molecular imaging of cancer

White light endoscopy has proven to be a very powerful tool in oncology. There is still, however, a need for better endoscopic techniques to overcome the current limitations of white light optics. New technologies that allow higher sensitivity, improved microanatomy and molecular characterization have been available for in vitro microscopy and are now being translated into in vivo endoscopy. Endoscopic molecular imaging is still in its infancy but holds the promise for enhancing sensitivity for early lesions, thus allowing earlier diagnosis and enabling early image-guided endoscopic intervention. A key feature of endoscopic molecular imaging is its increased sensitivity and specificity, which will be illustrated in this article, as well as describing perspectives on its future use in oncologic surgery.

Future directions for the early detection of colorectal cancer recurrence

Surgical resection remains a mainstay of treatment and is highly effective for localized colorectal cancer. However, ~30-40% of patients develop recurrence following surgery and 40-50% of recurrences are apparent within the first few years after initial surgical resection. Several variables factor into the ultimate outcome of these patients, including the extent of disease, tumor biology, and patient co-morbidities. Additionally, the time from initial treatment to the development of recurrence is strongly associated with overall survival, particularly in patients who recur within one year of their surgical resection. Current post-resection surveillance strategies involve physical examination, laboratory, endoscopic and imaging studies utilizing various high and low-intensity protocols. Ultimately, the goal is to detect recurrence as early as possible, and ideally in the asymptomatic localized phase, to allow initiation of treatment that may still result in cure. While current strategies have been effective, several efforts are evolving to improve our ability to identify recurrent disease at its earliest phase. Our aim with this article is to briefly review the options available and, more importantly, examine emerging and future options to assist in the early detection of colon and rectal cancer recurrence.

Chromocolonoscopy

Chromocolonoscopy is the process of endoscopically examining the colon mucosa after it has been stained with dye. The goal is to allow the endoscopist to identify subtle features in the mucosa, such as morphologically flat polyps or crypt patterns. Studies examining the efficacy of chromocolonoscopy to identify adenomas missed by conventional colonoscopy have shown that although chromocolonoscopy increases polyp yield, most additional lesions are small in size. Staining can also help in differentiating neoplastic from non-neoplastic polyps. Perhaps the most useful aspect of chromocolonoscopy is increasing the yield for dysplasia in patients undergoing colonoscopy for inflammatory bowel disease surveillance.