Endomicroscopy of Barrett's Esophagus

Endomicroscopy is a remarkable technical advance in gastrointestinal mucosa imaging. In 2003, Kiesslich and colleagues described the first human use of contrast-aided confocal laser endomicroscopy (CLE) as a novel technique for in vivo microscopic imaging of the gastrointestinal mucosa. Both probe-based and endoscope-based systems have been applied to many gastrointestinal disorders, including Barrett's esophagus (BE) and associated neoplasia. Probe-based confocal laser endomicroscopy can be used in conjunction with highresolution white light endoscopy and other contrast enhancement techniques. It has proven high accuracy for prediction of high-grade neoplasia and cancer. In vivo imaging of both flat BE and mucosal lesions can influence diagnosis and thereby impact upon decision making regarding tissue sampling and endoscopic therapy. This article discusses the scientific literature related to clinical use of CLE for BE, the techniques for performing CLE in the esophagus, and the potential future directions for CLE in BE and esophageal cancer diagnosis and treatment.     

Diagnosing Helicobacter pylori in vivo by confocal laser endoscopy

BACKGROUND & AIMS: Confocal laser endomicroscopy enables subsurface microscopic imaging of living tissue during ongoing endoscopy. This case report describes the in vivo detection of Helicobacter pylori by endomicroscopy. METHODS: Endomicroscopy (Pentax, Tokyo, EC-3870CIFK) was performed by using two different contrast stains: Topical Acriflavine in addition to intravenously applied fluorescein netted the surface and allowed identification of focal accumulation of Helicobacter pylori at the surface and in deeper layer of the gastric epithelium. Biopsies were performed at the antrum and corpus for urease testing and histology. In addition, biopsies were cultured for Helicobacter pylori. Cultured bacteria were re-assessed ex vivo using confocal microscopy with and without acriflavine staining. RESULTS: Helicobacter pylori infection could be detected in a 70-year-old male by endomicroscopy. Accumulated, as well as single bacteria, could be observed and the distinct shape and flagella of Helicobacter pylori could be identified. Helicobacter pylori infection was proved by histology. Furthermore, ex vivo examination of cultures proved the presence of Helicobacter pylori and the active uptake of acriflavine into the bacteria. CONCLUSIONS: Endomicroscopy is a new diagnostic approach, which enables the immediate diagnosis of Helicobacter pylori in vivo during standard video endoscopy.     

Virtual histology

Confocal laser endomicroscopy enables in vivo microscopy of the mucosal layer of the GI-tract with subcellular resolution during ongoing endoscopy. Endomicroscopy opens a new door for immediate tissue and vessel analysis. Different types of diseases can be diagnosed with optical surface and subsurface analysis. Analysis of the in vivo microarchitecture can be used for targeting biopsies to relevant areas. Furthermore, subsurface imaging can unmask microscopic diseases - (microscopic colitis) or bacterial infection (Helicobacter pylori), for example. Molecular imaging is becoming feasible, and this will shortly open the door to new indications in gastrointestinal endoscopy. This chapter reviews the currently rapidly expanding clinical data about endomicroscopy and gives a look into future research.     

共聚焦激光显微内镜在胃癌和胃癌前变化诊断中的应用

目前,胃癌和胃癌前变化诊断主要依赖于活检组织病理检查。共聚焦激光显微内镜是一种新型显微内镜,其能在体内实时显示胃肠道组织、细胞和亚细胞结构,准确鉴别胃肠道正常、增生或瘤变的黏膜。共聚焦激光显微内镜在在体实时诊断胃癌和包括萎缩性胃炎、肠上皮化生和上皮内瘤变等在内的胃癌前变化方面已展现了其优势和价值。本文就共聚焦激光显微内镜在胃癌和胃癌前变化诊断中的应用进展作一介绍。     

Confocal laser endomicroscopy diagnosis of gastric adenocarcinoma in a patient treated for gastric diffuse large-B-cell lymphoma

The association between gastric carcinoma and lymphoma is rare. Confocal laser endomicroscopy is a new diagnostic tool that allows the identification of cellular and vascular architecture during endoscopy. This is the first report of an in vivo early gastric carcinoma diagnosis by confocal laser endomicroscopy in a patient successfully treated for a primary gastric diffuse large-B-cell lymphoma.     

In vivo histology of Barrett's esophagus and associated neoplasia by confocal laser endomicroscopy.

BACKGROUND & AIMS: Confocal laser endomicroscopy allows subsurface analysis of the intestinal mucosa and in vivo histology during ongoing endoscopy. Here, we have applied this technique to the in vivo diagnosis of Barrett's epithelium and associated neoplasia. METHODS: Fluorescein-aided endomicroscopy was performed by applying the endomicroscope over the whole columnar-lined lower esophagus. Images obtained within 1 cm of the columnar-lined lower esophagus were stored digitally and a targeted biopsy examination or endoscopic mucosal resection of the examined areas was performed. In vivo histology was compared with the histologic specimens. All digitally stored images were re-assessed by a blinded investigator by the confocal Barrett classification system to predict histology. Intraobserver and interobserver variations of the involved endoscopists were evaluated by using kappa statistics. RESULTS: Endomicroscopy allowed distinguishing between different types of epithelial cells and detected cellular and vascular changes in Barrett's epithelium at high resolution during ongoing endoscopy in 63 patients. Barrett's esophagus and associated neoplasia could be predicted with a sensitivity of 98.1% and 92.9% and a specificity of 94.1% and 98.4%, respectively (accuracy, 96.8% and 97.4%). The mean kappa value for interobserver agreement for the prediction of histopathological diagnosis was .843, whereas the intraobserver agreement showed a mean kappa value of .892. CONCLUSIONS: Fluorescence-aided endomicroscopy of Barrett's esophagus allows in vivo histology of the mucosal layer during ongoing endoscopy. Gastric and Barrett's epithelium and Barrett's-associated neoplastic changes can be diagnosed with high accuracy. Thus, endomicroscopy may be helpful in the management of patients with Barrett's esophagus.     

Chromoscopic endomicroscopy: In vivo cellular resolution imaging of the colorectum

Advances in imaging technology and engineering have now permitted functional integration of a confocal endomicroscope into the distal tip of a conventional video colonoscope enabling imaging of the surface epithelium and the underlying lamina propria during ongoing video endoscopy. For the first time, the endoscopist is now able to resolve the surface and subsurface mucosa at cellular resolution in vivo and in real time. A new era in endoscopic imaging has therefore begun – histoendoscopy. In addition to providing a high-accuracy in vivo optical biopsy tool for the differentiation between benign hyperplasia, intra-epithelial neoplasia and carcinoma in sporadic cohorts, endomicroscopy with targeted biopsies has now been shown to increase the yield of intra-epithelial neoplasia complicating ulcerative colitis. Furthermore, recent data examining endomicroscopic molecular ex vivo imaging using anti-CD44v6 antibody has identified aberrant crypt foci based on their surface molecular expression. Receptor overexpression in vivo in humans may, in the near future, be exploited for the diagnosis of inflammation, neoplasia and in predicting targeted molecular therapy. Endomicroscopy will be key to this immuno-imaging interface. Within the present review, we discuss the current clinical evidence in support of confocal endomicroscopy and explore the new diagnostic possibilities for this technology.     

Ultra high magnification endoscopy: Is seeing really believing?

Endoscopy is an indispensible diagnostic and thera-peutic instrument for gastrointestinal diseases. Endo-cytoscopy and confocal endomicroscopy are two types of ultra high magnification endoscopy techniques.Standard endoscopy allows for 50 × magnification,whereas endocytoscopy can magnify up to 1400 × and confocal endomicroscopy can magnify up to 1000 ×.These methods open the realm of real time micros copicevaluation of the GI tract, including cellular and subcellular structures. Confocal endomicroscopy has the additional advantage of being able to visualize subsurface structures. The use of high magnification endoscopy inconjunction with standard endoscopy allows for a real-time microscopic assessment of areas with macroscopic abnormalities, providing "virtual biopsies" with valuable information about cellular and subcellular changes. Thiscan minimize the number of biopsies taken at the time of endoscopy. The use of this technology may assistin detecting premalignant or malignant changes at anearlier state, allowing for earlier intervention and treatment. High magnification endoscopy has shown promising results in clinical trials for Barrett’s esophagus,esophageal adenocarcinoma, esophageal squamous cell cancer, gastric cancer, celiac disease, colorectalcancer, and inflammatory bowel disease. As the use of high magnification endoscopy techniques increases,the clinical applications will increase as well. Of the two systems, only confocal endomicroscopy is currently commercially available. Like all new technologies there will be an initial learning curve before operators become proficient in obtaining high quality images and discerning abnormal from normal pathology. Validatedcriteria for the diagnosis of the various gastrointestinal diseases will need to be developed for each method. Inthis review, the basic principles of both modalities are discussed, along with their clinical applic ability and limitations.     

微探头共聚焦显微内镜诊断胃黏膜病变的初步应用

目的:探讨Cellvizio微探头式共聚焦内镜诊断胃黏膜病变的能力。方法:收集门诊6例胃黏膜病变患者行Cellvizio微探头式共聚焦内镜检查术。检查中静脉注射荧光素钠作为荧光剂。每例患者均经内镜直视诊断、共聚焦微探头诊断并获取靶向活组织行病理检查。符合手术指征者行外科手术。结果:6例患者共7处病灶,其中息肉2处,黏膜粗糙、发红2处,浅表凹陷灶1处,隆起伴凹陷灶1处,深溃疡1处。所有患者均完成共聚焦内镜检查,共获得连续视频图像32段。微探头共聚焦内镜易于操作其诊断正确者为6例(6/7),未发生明显不良反应。结论:Cellvizio微探头式共聚焦内镜操作简便,即时成像,是有效的胃黏膜病变诊断手段。     

Endoscopic ultrasonography: Transition towards the future of gastro-intestinal diseases

Endoscopic ultrasonography(EUS) is a technique with an established role in the diagnosis and staging of gastro-intestinal tumors. In recent years, the spread of new devices dedicated to tissue sampling has improved the diagnostic accuracy of EUS fine-needle aspiration. The development of EUS-guided drainage of the biliopancreatic region and abdominal fluid collections has allowed EUS to evolve into an interventional tool that can replace more invasive procedures. Emerging techniques applying EUS in pancreatic cancer treatment and in celiac neurolysis have been described. Recently, confocal laser endomicroscopy has been applied to EUS as a promising technique for the in vivo histological diagnosis of gastro-intestinal, bilio-pancreatic and lymph node lesions. In this state-of-the-art review, we report the most recent data from the literature regarding EUS devices, interventional EUS, EUS-guided confocal laser endomicroscopy and EUS pancreatic cancer treatment, and we also provide an overview of their principles, clinical applications and limitations.     

Frontiers in bronchoscopic imaging

Bronchoscopy is a minimally invasive method for diagnosis of diseases of the airways and the lung parenchyma. Standard bronchoscopy uses the reflectance/scattering properties of white light from tissue to examine the macroscopic appearance of airways. It does not exploit the full spectrum of the optical properties of bronchial tissues. Advances in optical imaging such as optical coherence tomography (OCT), confocal endomicroscopy, autofluorescence imaging and laser Raman spectroscopy are at the forefront to allow in vivo high-resolution probing of the microscopic structure, biochemical compositions and even molecular alterations in disease states. OCT can visualize cellular and extracellular structures at and below the tissue surface with near histological resolution, as well as to provide three-dimensional imaging of the airways. Cellular and subcellular imaging can be achieved using confocal endomicroscopy or endocytoscopy. Contrast associated with light absorption by haemoglobin can be used to highlight changes in microvascular structures in the subepithelium using narrow-band imaging. Blood vessels in the peribronchial space can be displayed using Doppler OCT. Biochemical compositions can be analysed with laser Raman spectroscopy, autofluorescence or multispectral imaging. Clinically, autofluorescence and narrow-band imaging have been found to be useful for localization of preneoplastic and neoplastic bronchial lesions. OCT can differentiate carcinoma in situ versus microinvasive cancer. Endoscopic optical imaging is a promising technology that can expand the horizon for studying the pathogenesis and progression of airway diseases such as COPD and asthma, as well as to evaluate the effect of novel therapy.     

New endoscopic approaches in IBD

Recent advances in endoscopic imaging techniques have revolutionized the diagnostic approach of patients with inflammatory bowel disease(IBD).New,emerging endoscopic imaging techniques visualized a plethora of new mucosal details even at the cellular and subcellular level.This review offers an overview about new endoscopic techniques,including chromoendoscopy,magnification endoscopy,spectroscopy,confocal laser endomicroscopy and endocytoscopy in the face of IBD.     

Confocal laser endomicroscopy for in vivo diagnosis of Barrett's oesophagus and associated neoplasia: A pilot study conducted in a single Italian centre

BackgroundDiagnosis and management of Barrett's oesophagus are controversial. Technical improvements in real-time recognition of intestinal metaplasia and neoplastic foci provide the chance for more effective target biopsies. Confocal laser endomicroscopy allows to analyze living cells during endoscopy.AimsTo assess the diagnostic accuracy, inter- and intra-observer variability of endomicroscopy for detecting in vivo neoplasia (dysplasia and/or early neoplasia) in Barrett's oesophagus.MethodsProspective pilot study. Patients referred for known Barrett's oesophagus were screened. Endomicroscopy was carried out in a circular fashion, every 1–2 cm, on the whole columnar-lined distal oesophagus. Visible lesions, when present, were analyzed first. Targeted biopsies were taken. Confocal images were classified according to confocal Barrett classification. Endomicroscopic and histological findings were compared.ResultsForty-eight out of 50 screened patients underwent endomicroscopy. Visible lesions were observed in 3 patients. In a per-biopsy analysis, Barrett's-oesophagus-associated neoplasia could be predicted with an accuracy of 98.1%. The agreement between endomicroscopic and histological results was substantial (κ = 0.76).ConclusionsThis study suggests that endomicroscopy can provide in vivo diagnosis of Barrett's oesophagus-associated neoplasia. Because it allows for the study of larger surface areas of the mucosa, endomicroscopy may lead to significant improvements in the in vivo screening and surveillance of Barrett's oesophagus.     

Chromoscopy-guided endomicroscopy increases the diagnostic yield of intraepithelial neoplasia in ulcerative colitis

BACKGROUND AND AIMS: Because of the large number of biopsy specimens, surveillance colonoscopy in ulcerative colitis (UC) is currently time consuming and significant flat lesions still may be missed. In this study we assessed the value of combined chromoscopy and endomicroscopy for the diagnosis of intraepithelial neoplasias in a randomized controlled trial. METHODS: A total of 161 patients with long-term UC in clinical remission were randomized at a 1:1 ratio to undergo conventional colonoscopy or chromoscopy with endomicroscopy. Eight patients were excluded because of insufficient bowel preparation. In the conventional colonoscopic group (n = 73), random biopsy examinations and targeted biopsy examinations were performed. In the endomicroscopy group (n = 80), circumscribed mucosal lesions were identified by chromoscopy and evaluated for targeted biopsy examination by endomicroscopy. The primary outcome analysis was based on the detection of neoplasias. RESULTS: By using chromoscopy with endomicroscopy, 4.75-fold more neoplasias could be detected (P = .005) than with conventional colonoscopy, although 50% fewer biopsy specimens (P = .008) were required. If only circumscribed lesions would have been biopsied in the first group, the total number of biopsy specimens could have been reduced by more than 90%. A total of 5580 confocal endomicroscopic images from 134 circumscribed lesions were compared with histologic results. The presence of neoplastic changes could be predicted by endomicroscopy with high accuracy (sensitivity, 94.7%; specificity, 98.3%; accuracy, 97.8%). CONCLUSIONS: Endomicroscopy based on in vivo histology can determine if UC lesions identified by chromoscopy should undergo biopsy examination, thereby increasing the diagnostic yield and reducing the need for biopsy examinations. Thus, chromoscopy-guided endomicroscopy may lead to significant improvements in the clinical management of UC.     

Confocal endomicroscopy for in vivo detection of microvascular architecture in normal and malignant lesions of upper gastrointestinal tract

Background and Aim: Confocal laser endomicroscopy allows subsurface analysis of gastrointestinal mucosa during ongoing endoscopy. The present study assessed the feasibility of in vivo detecting superficial vascular architecture by confocal endomicroscopy in normal upper gastrointestinal mucosa and malignant lesions. Methods: Early gastric cancer in eight patients, superficial esophageal carcinoma in six patients, and asymptomatic normal control in 10 patients were studied by confocal endomicroscopy. The characteristic of endomicroscopic microvascular architecture from normal and malignant mucosa was described and images were evaluated. Results: Confocal endomicroscopy enabled clear visualization of the vascular networks of gastroesophageal mucosa. Honeycomb‐like and coil‐shaped regular microvascular architecture surrounding gastric pits were visible in the normal gastric body and antrum, respectively. Differentiated gastric cancerous mucosa showed hypervascularity and various caliber microvessels with irregular shapes. Undifferentiated gastric cancers disclosed a hypovascularity and irregular short branch vessels. Normal squamous epithelium had regular intraepithelial papillary capillary loops (IPCLs) directed toward the luminal surface. In superficial esophageal squamous carcinoma, dilated IPCLs were visible at the upper layer of the squamous mucosa. In esophageal adenocarcinoma, abnormal microvascular architecture showed tortuous and various calibers blood vessels. Of all the images, 41% were graded as good quality. The mean kappa value for interobserver agreement for the prediction of cancerous mucosa was 0.792. Conclusions: Confocal laser endomicroscopy system could yield very clear images of superficial microvascular network in the gastroesophageal mucosal layer both in malignant and normal mucosa. Endomicroscopic observation of vascular architecture may be of assistance in the identification of early gastroesophageal cancers.     

Confocal laser endomicroscopy in the ＂in vivo＂ histological diagnosis of the gastrointestinal tract

Recent technological advances in miniaturization have allowed for a confocal scanning microscope to be integrated into a conventional flexible endoscope, or into trans-endoscopic probes, a technique now known as confocal endomicroscopy or confocal laser endomicroscopy. This newly-developed technology has enabled endoscopists to collect real-time in vivo histological images or "virtual biopsies" of the gastrointestinal mucosa during endoscopy, and has stimulated significant interest in the application of this technique in clinical gastroenterology. This review aims to evaluate the current data on the technical aspects and the utility of this new technology in clinical gastroenterology and its potential impact in the future, particularly in the screening or surveillance of gastrointestinal neoplasia.     

Pilot study on confocal endomicroscopy for determination of the depth of squamous cell esophageal cancer in vivo

Background and Aim:  Confocal endomicroscopy is ultra-high-magnification endoscopy with histological observation during ongoing endoscopy. We planned a pilot study of the diagnosis of the depth of esophageal cancer using confocal endomicroscopy for treatment strategies.
Methods:  Patients had 14 superficial esophageal cancers and one dysplasia. The depth of neoplasms in 15 lesions was confirmed by endoscopic mucosal resection or surgery.
We examined the rate of delineation and compared results of confocal imaging with histological findings. We classified two cellular and three microvascular patterns on confocal endomicroscopic images: CP-N for normal squamous mucosa and CP-Ca for cancerous lesion; VP-type A for normal squamous mucosa; VP-type B for T1a-EP and T1a-LPM cancers; and VP-type C for T1a-MM or a more invasive cancer pattern. We measured diameters of microvessels for the three patterns of confocal endomicroscopic images and histological specimens.
Results:  The rate of delineation was 73.3% (11/15) for esophageal cancer. The results of confocal imaging coincided well with microvessel distribution on horizontal histology. Two endoscopists blindly diagnosed the two types by cellular pattern and the three types by vascular pattern: their overall accuracies were 96% and 89% for the cellular pattern and 85% and 85% for the vascular pattern, respectively. The k value of the cellular pattern and the vascular pattern diagnosis was 0.84 and 0.75, respectively.
Conclusion:  Scoring and quantification of confocal endomicroscopic images may be useful for the differential diagnosis and diagnosis of superficial invasion by squamous cell carcinoma.     

Chromoendoscopy: what is its true value for ulcerative colitis surveillance?

Advanced imaging technologies are enabling targeted biopsies or endoscopic resections due to better visualization of the mucosal architecture. This new concept of 'smart biopsies' is in particular important for patients with higher risk for development cancer (e.g. ulcerative colitis) but can also be beneficial for screening purposes. This short review will focus on new imaging modalities like chromoendoscopy, digital chromoendoscopy, high-definition endoscopy and confocal laser endomicroscopy in the lower GI tract which will be crucial in the future to detect colorectal neoplasia earlier then before.     

Endomicroscopy for assessing mucosal healing in patients with ulcerative colitis

The assessment of tissue healing has emerged as an important treatment goal in patients with inflammatory bowel disease. In patients with ulcerative colitis (UC), mucosal healing may represent the ultimate therapeutic goal due to the fact that the inflammation is limited to the mucosal layer. Mucosal and histological healing may indicate a subset of UC patients in long-term clinical, endoscopic and histological remission in whom immunomodulators, biologics, and even aminosalicylates may be withdrawn. Confocal laser endomicroscopy allows the assessment of residual cellular inflammation, crypt and vessel architecture distortion during ongoing endoscopy, and therefore permits a real-time evaluation of histological healing in patients with ulcerative proctitis. Images of conventional optical microscopy and confocal laser endomicroscopy in patients with ulcerative proctitis in remission are presented.     

共聚焦内镜诊断Barrett食管的初步研究

目的评价共聚焦内镜对Barrett食管的诊断价值。方法选取胃镜检查疑诊为Barrett食管患者纳入研究,以荧光素钠作为荧光对比剂,进行共聚焦内镜检查。对食管下段柱状上皮间隔2 cm进行四象限检查,并检查局部黏膜粗糙部位,随后对所检查部位黏膜活检。进行共聚焦显微内镜检查后即刻预测组织学诊断,并与病理组织学诊断进行对比。结果对入选的21例患者共进行食管下段70个部位共聚焦内镜检查,最终组织学诊断为:Barrett食管上皮部位41个,食管腺癌部位5个,胃型黏膜部位24个。对源自70个部位的全部2150帧共聚焦图像与组织学资料进行比较,共聚焦内镜诊断Barrett食管的敏感度为95.0%,特异度为90.0%,准确度为85.0%,阳性预测值为92.7%,阴性预测值为93.1%。结论共聚焦内镜可在内镜检查实时进行黏膜组织学检查,诊断Barrett食管敏感度和特异度高,为Barrett食管的诊断提供新的有力工具。