Optical coherence tomography in detection of dysplasia and cancer of the gastrointestinal tract and bilio-pancreatic ductal system

Optical coherence tomography （OCT） is an optical imaging modality that performs high-resolution, crosssectional, subsurface tomographic imaging of the microstructure of tissues. The physical principle of OCT is similar to that of B-mode ultrasound imaging, except that it uses infrared light waves rather than acoustic waves. The in vivo resolution is 10-25 times better （about 10 μm） than with high-frequency ultrasound imaging, but the depth of penetration is limited to 1-3 mm, depending upon tissue structure, depth of focus of the probe used, and pressure applied to the tissue surface. In the last decade, OCT technology has evolved from an experimental laboratory tool to a new diagnostic imaging modality with a wide spectrum of clinical applications in medical practice, including the gastrointestinal （GI） tract and pancreatic-biliary ductal system. OCT imaging from the GI tract can be done in humans by using narrowdiameter, catheter-based probes that can be inserted through the accessory channel of either a conventional front-view endoscope, for investigating the epithelial structure of the GI tract, or a side-view endoscope, inside a standard transparent ERCP catheter, for investigating the pancreatico-biliary ductal system. Esophagus and the esophago-gastric junction has been the most widely investigated organ so far; more recently, also duodenum, colon and pancreatico-biliary ductal system have been extensively investigated. OCT imaging of the gastrointestinal wall structure is characterized by a multiplelayer architecture that permits an accurate evaluation of the mucosa, lamina propria, muscularis mucosae, andpart of the submucosa. The technique may be, therefore, used to identify pre-neoplastic conditions of the GI tract, such as Barrett＇s epithelium and dysplasia, and evaluate the depth of penetration of early-stage neoplastic lesions. OCT imaging of the pancreatic and biliary ductal system could improve the diagnostic accuracy for ductal epithelial changes and the differential diagnosis betw     

Toll-like receptor 4 activation in Barrett’s esophagus results in a strong increase in COX-2 expression

Background

Barrett’s esophagus (BE) is known to progress to esophageal adenocarcinoma in a setting of chronic inflammation. Toll-like receptor (TLR) 4 has been linked to inflammation-associated carcinogenesis. We aimed to determine the expression and functional activity of TLR4 in the esophagus and whether TLR4 activation in BE could promote carcinogenesis by inducing COX-2 expression.

Methods

TLR4 expression in esophageal adenocarcinoma, BE, duodenum, reflux esophagitis and normal squamous esophagus biopsies was assessed using real-time PCR and validated by in situ hybridization and immunohistochemistry. Ex vivo cultures of BE, duodenum and normal squamous esophagus biopsies and a BE cell line (BAR-T) were stimulated with the TLR4 agonist lipopolysaccharide (LPS). To evaluate the effect of TLR4 activation, NF-κB activation, IL8 secretion and expression and COX-2 expression were determined.

Results

TLR4 expression was significantly increased in esophageal adenocarcinoma, BE, duodenum and reflux esophagitis compared to normal squamous esophagus. LPS stimulation resulted in NF-κB activation and a dose-dependent increase of IL8 secretion and mRNA expression. The induction of IL8 was more evident in BE compared to normal squamous esophagus. Upon LPS stimulation, COX-2 expression increased significantly in ex vivo cultured BE biopsies, which was observed in both epithelium and lamina propria cells. However, no effect was found in duodenum and normal squamous esophagus biopsies.

Conclusion

TLR4 activation in BE results in a strong increase in COX-2 and may contribute to malignant transformation.     

Improved biopsy accuracy in Barrett’s esophagus with a transparent cap

AIM:To evaluate the efficacy of endoscopy with a transparent cap on biopsy positioning in Barrett’s esophagus(BE).METHODS:One hundred and sixty-eight patients with suspected BE at endoscopy were enrolled in our study from November 2007 to December 2009 and divided into two groups:transparent cap group(n=60)and control group(n=108).Endoscopy with or without a transparent cap and subsequent biopsy of suspected lesions were performed by five experienced endoscopists in our hospital.In both groups,two biopsy specimens were taken from each patient,and the columnar epithelium or goblet cells in histological assessment were used as the diagnostic standard for BE.RESULTS:In the transparent cap group,41 cases were tongue type,while 17 and two cases were identified as island type and circumferential type,respectively.In the control group,65 tongue-type cases were confirmed,with 38 island-type and five circumferential-type cases.Moreover,there was no significant difference with regard to the composition of endoscopic BE types in the two groups(P>0.05).In the biopsy specimens,BE was detected in 50 cases in the transparent cap group(83.3%,50/60),whereas the detection rate in the control group(69.4%,75/108)was lower compared to that in the transparent cap group(P<0.05).In addition,goblet cells were recognized in only eight cases(all with columnar epithelium)(8/60,13.3%)in the transparent cap group,with 11 cases in the control group.CONCLUSION:Transparent cap-fitted endoscopy can guide biopsy positioning in BE without other accompanying complications,thus increasing the detection rate of BE.     

A fluorescence confocal endomicroscope for in vivo microscopy of the upper- and the lower-GI tract

BACKGROUND: This report describes the development and the clinical evaluation of a novel confocal endomicroscope for obtaining fluorescence images of cellular morphology of the mucosae of the upper- and the lower-GI tract in vivo. The work assessed the feasibility of performing in vivo microscopy at endoscopic examination and evaluated fluorescence imaging protocols. METHODS: Images were collected in real time by using two prototype endoscope configurations, featuring slightly different miniaturized fiber-optic confocal microscopes, fitted integrally into the tips of conventional endoscopes. Confocal scanning was performed at 488 nm illumination for excitation of exogenously applied fluorophores (topical acriflavine and intravenous fluorescein). The images were compared with conventional histology of biopsy specimens and the findings of white-light endoscopy. RESULTS: Confocal endomicroscopy enabled imaging of cellular and subcellular structures (i.e., nuclei) of the GI tract. The crypts of the colonic mucosa, the villi of the terminal ileum and duodenum, the gastric pits of the stomach, and the squamous epithelium of the distal esophagus could be clearly visualized. Acriflavine strongly contrasted the cell nuclei of the surface epithelium, including the absorptive epithelial cells and the mucous secreting goblet cells. Fluorescein stained the extracellular matrix of the surface epithelium and also the subepithelial layers of the lamina propria. Images at increasing depth beneath the epithelium showed the mucosal capillary network. The findings correlated with the histology of biopsy specimens. CONCLUSIONS: The development of a fluorescence confocal endomicroscope makes it practical to examine the upper- and the lower-GI mucosa in cellular detail during otherwise routine endoscopic examination. The results represent a major technical advance in the development of this new optical imaging modality for the in vivo examination of GI tissue.     

Endoscopic imaging of Barrett’s esophagus

The incidence of esophageal adenocarcinoma(EAC) has dramatically increased in the United States as well as Western European countries. The majority of esophageal adenocarcinomas arise from a backdrop of Barrett’s esophagus(BE),a premalignant lesion that can lead to dysplasia and cancer. Because of the increased risk of EAC,GI society guidelines recommend endoscopic surveillance of patients with BE. The emphasis on early detection of dysplasia in BE through surveillance endoscopy has led to the development of advanced endoscopic imaging technologies. These techniques have the potential to both improve mucosal visualization and characterization and to detect small mucosal abnormalities which are difficult to identify with standard endoscopy. This review summarizes the advanced imaging technologies used in evaluation of BE.     

Radical excision of Barrett’s esophagus and complete recovery of normal squamous epithelium

To treat Barrett’s esophagus(BE),radiofrequency ablation or cryotherapy are effective treatments for eradicating BE with dysplasia and intestinal metaplasia,and reduce the rates of Barrett’s esophageal adenocarcinoma(BAC).However,patients with BE and dysplasia or early cancer who achieved complete eradication of intestinal metaplasia,BE recurred in 5% within a year,requiring expensive endoscopic surveillances.We performed endoscopic submucosal dissection as complete radically curable treatment procedure for BE with dysplasia,intestinal metaplasia and BAC.     

Assessment of the diagnostic performance and interobserver variability of endocytoscopy in Barrett’s esophagus:A pilot ex-vivo study

AIM:To investigate a classification of endocytoscopy(ECS)images in Barrett’s esophagus(BE)and evaluate its diagnostic performance and interobserver variability.METHODS:ECS was applied to surveillance endoscopic mucosal resection(EMR)specimens of BE ex-vivo.The mucosal surface of specimen was stained with 1%methylene blue and surveyed with a catheter-type endocytoscope.We selected still images that were most representative of the endoscopically suspect lesion and matched with the final histopathological diagnosis to accomplish accurate correlation.The diagnostic performance and inter-observer variability of the new classification scheme were assessed in a blinded fashion by physicians with expertise in both BE and ECS and inexperienced physicians with no prior exposure to ECS.RESULTS:Three staff physicians and 22 gastroenterology fellows classified eight randomly assigned unknown still ECS pictures(two images per each classification)into one of four histopathologic categories as follows:(1)BEC1-squamous epithelium;(2)BEC2-BE without dysplasia;(3)BEC3-BE with dysplasia;and(4)BEC4-esophageal adenocarcinoma(EAC)in BE.Accuracy of diagnosis in staff physicians and clinical fellows were,respectively,100%and 99.4%for BEC1,95.8%and83.0%for BEC2,91.7%and 83.0%for BEC3,and95.8%and 98.3%for BEC4.Interobserver agreement of the faculty physicians and fellows in classifying each category were 0.932 and 0.897,respectively.CONCLUSION:This is the first study to investigate classification system of ECS in BE.This ex-vivo pilot study demonstrated acceptable diagnostic accuracy and excellent interobserver agreement.     

Management strategies of Barrett's esophagus

Barrett’s esophagus is a condition resulting from chronic gastro-esophageal reflux disease with a documented risk of esophageal adenocarcinoma. Current strategies for improved survival in patients with Barrett''s adenocarcinoma focus on detection of dysplasia. This can be obtained by screening programs in high-risk cohorts of patients and/or endoscopic biopsy surveillance of patients with known Barrett’s esophagus (BE). Several therapies have been developed in attempts to reverse BE and reduce cancer risk. Aggressive medical management of acid reflux, lifestyle modifications, antireflux surgery, and endoscopic treatments have been recommended for many patients with BE. Whether these interventions are cost-effective or reduce mortality from esophageal cancer remains controversial. Current treatment requires combinations of endoscopic mucosal resection techniques to eliminate visible lesions followed by ablation of residual metaplastic tissue. Esophagectomy is currently indicated in multifocal high-grade neoplasia or mucosal Barrett’s carcinoma which cannot be managed by endoscopic approach.     

Identification of the layered morphology of the esophageal wall by optical coherence tomography

AIM： To assess each layer of the optical coherence tomography （OCT） image of the esophageal wall with reference to the histological structure, METHODS： Resected specimens of fresh pig esophagus was used as a model for the esophageal wall. We injected cyanoacrylate adhesive into the specimens to create a marker, and scanned them using a miniature OCT probe. The localization of these markers was assessed in the OCT images. Then we compared the OCT-imaged morphology with the corresponding histological section, guided by the cyanoacrylate adhesive markers. We prepared a second set of experiments using nylon sutures as markers. RESULTS： The OCT image of the esophageal specimen has a clear five-layered morphology. First, it consisted of a relatively less reflective layer; second, a more reflective layer; third, a less reflective layer; fourth, a more reflective layer; and fifth, a less reflective layer. Comparing the OCT images with marked histological sections showed that the first layer corresponded to stratified squamous epithelium; the second to lamina propria; the third to muscularis mucosa; fourth, submucosa; and fifth, muscularis propria with deeper structures of the esophageal wa CONCLUSION： We demonstrated that the OCT image of the normal esophageal wall showed a five- layered morphology, which corresponds to histological esophageal wall components.     

Impairment of secondary peristalsis in Barrett’s esophagus by transnasal endoscopy-based testing

AIM:To investigate dysfunctions in esophageal peristalsis and sensation in patients with Barrett’s esophagus following acid infusion using endoscopy-based testing.METHODS:First,physiological saline was infused into the esophagus of five healthy subjects,at a rate of 10 mL/min for 10 min,followed by infusion of HCl.Esophageal contractions were analyzed to determine whether the contractions observed by endoscopy and ultrasonography corresponded to the esophageal peristaltic waves diagnosed by manometry.Next,using nasal endoscopy,esophageal sensations and contractions were investigated in patients with,as well as controls without,Barrett’s esophagus using the same infusion protocol.RESULTS:All except one of the propulsive contractions identified endoscopically were recorded as secondary peristaltic waves by manometry.Patients with long segment Barrett’s esophagus(LSBE)tended to have a shorter lag time than the control group,although the difference did not reach statistical significance(88±54s vs 162±150 s respectively,P=0.14).Furthermore,patients with LSBE had significantly fewer secondary contractions following the infusion of both saline and HCl than did either the control group or patients with short segment Barrett’s esophagus(4.1±1.2 vs 8.0±2.8,P<0.001 and 7.3±3.2,P<0.01,respectively,following saline infusion;5.3±1.2vs 8.4±2.4 and 8.1±2.9 respectively,P<0.01 for both,following infusion of HCl).CONCLUSION:Using nasal endoscopy and a simple acid-perfusion study,we were able to demonstrate disorders in secondary peristalsis in patients with LSBE.     

Correlation of endoscopic optical coherence tomography with histology in the lower-GI tract

BACKGROUND: Optical coherence tomography (OCT), a noninvasive optical imaging technique, provides high-resolution cross-sectional images of tissue microstructure. We developed a system for real-time endoscopic OCT (EOCT) of the human GI tract. During clinical trials, the structure of mucosa and submucosa, glands, blood vessels, pits, villi, and crypts was observed in a range of GI organs. Although EOCT images are thought to accurately depict actual histologic features, there are few data to support this assumption. Therefore, the present study correlated images acquired with an EOCT imaging system in vitro to corresponding histologic sections. METHODS: EOCT images were obtained of fresh specimens of ileum, colon, and rectum that then were fixed in formalin and were processed for microscopic evaluation by using standard methods. The thickness of mucosa and of submucosa was determined for both EOCT images and histologic slides. RESULTS: The first hyper-reflective layer in the EOCT images was identified as mucosa. A close correlation (R 2=0.84) was observed between EOCT and histology. Furthermore, the submucosa and the muscularis propria could be identified as the next deepest hyporeflective band and a hyper-reflective layer, respectively, in EOCT images. The submucosa was found to be more compressible than mucosa, and its EOCT appearance was dependent on its content of adipose tissue. CONCLUSIONS: EOCT provides images that precisely correlate with the histologic structure of the mucosa and the submucosa of the GI tract.     

Microvasculature of the esophagus and gastroesophageal junction: Lesson learned from submucosal endoscopy

Advanced therapeutic endoscopy,in particular endoscopic mucosal resection,endoscopic submucosal dissection,per-oral endoscopic myotomy,submucosal endoscopic tumor resection opened a new era where direct esophageal visualization is possible.Combining these information with advanced diagnostic endoscopy,the esophagus is organized,from the luminal side to outside,into five layers(epithelium,lamina propria with lamina muscularis mucosa,submucosa,muscle layer,adventitia).A specific vascular system belonging to each layer is thus visible: Mucosa with the intra papillary capillary loop in the epithelium and the sub-epithelial capillary network in the lamina propria and,at the lower esophageal sphincter(LES) level with the palisade vessels; submucosa with the drainage vessels and the spindle veins at LES level; muscle layer with the perforating vessels; periesophageal veins in adventitia.These structures are particularly important to define endoscopic landmark for the gastro-esophageal junction,helpful in performing submucosal therapeutic endoscopy.     

Shape of Barrett��s epithelium is associated with prevalence of erosive esophagitis

AIM: To test the hypothesis that the shape and length of Barrett’s epithelium are associated with prevalence of erosive esophagitis.METHODS: A total study population comprised 869 patients who underwent endoscopy during a health checkup at our hospital. The presence and extent of Barrett’s epithelium were diagnosed based on the Prague C & M Criteria. We originally classified cases of Barrett’s epithelium into two types based on its shape, namely, flame-like and lotus-like Barrett’s epithelium, and into two groups based on its length, its C extent < 2 cm, and ≥ 2 cm. Correlation of shape and length of Barrett’s epithelium with erosive esophagitis was examined.RESULTS: Barrett’s epithelium was diagnosed in 374 cases (43%). Most of these were diagnosed as short-segment Barrett’s epithelium. The prevalence of erosive esophagitis was significantly higher in subjects with flame-like than lotus-like Barrett’s epithelium, and in those with a C extent of ≥ 2 cm than < 2 cm.CONCLUSION: Flame-like rather than lotus-like Barrett’s epithelium, and Barrett’s epithelium with a longer segment were more strongly associated with erosive esophagitis.     

Endoscopic appearance of AIDS-related gastrointestinal lymphoma with c-MYC rearrangements: Case report and literature review

Acquired immune deficiency syndrome (AIDS)-related lymphoma (ARL) remains the main cause of AIDS-related deaths in the highly active anti-retroviral therapy (HAART) era. Recently, rearrangement of MYC is associated with poor prognosis in patients with diffuse large B-cell lymphoma. Here, we report a rare case of gastrointestinal (GI)-ARL with MYC rearrangements and coinfected with Epstein-Barr virus (EBV) infection presenting with various endoscopic findings. A 38-yearold homosexual man who presented with anemia and was diagnosed with an human immunodeficiency virus infection for the first time. GI endoscopy revealed multiple dish-like lesions, ulcerations, bloody spots, nodular masses with active bleeding in the stomach, erythematous flat lesions in the duodenum, and multiple nodular masses in the colon and rectum. Magnified endoscopy with narrow band imaging showed a honeycomb-like pattern without irregular microvessels in the dish-like lesions of the stomach. Biopsy specimens from the stomach, duodenum, colon, and rectum revealed diffuse large B-cell lymphoma concomitant with EBV infection that was detected by high tissue EBV-polymerase chain reaction levels and Epstein-Barr virus small RNAs in situ hybridization. Fluorescence in situ hybridization analysis revealed a fusion between the immunoglobulin heavy chain (IgH) and c-MYC genes, but not between the IgH and BCL2 loci. After 1-mo of treatment with HAART and R-CHOP, endoscopic appearance improved remarkably, and the histological features of the biopsy specimens revealed no evidence of lymphoma. However, he died from multiple organ failure on the 139 th day after diagnosis. The cause of his poor outcome may be related to MYC rearrangement. The GI tract involvement in ARL is rarely reported, and its endoscopic findings are various and may be different from those in non-AIDS GI lymphoma; thus, we also conducted a literature review of GI-ARL cases.     

The inaccuracy of ICD-9-CM Code 530.2 for identifying patients with Barrett's esophagus

SUMMARY.  Barrett's esophagus (BE) is a chronic complication associated with gastroesophageal reflux disease. The ICD-9-CM code used for BE, 530.2, is also used for patients with 'ulcer of the esophagus.' We aimed to determine if the ICD-9-CM code of 530.2 is reliable for identifying cases of Barrett's esophagus within databases for research purposes. We reviewed the records of all patients assigned code 530.2 at two university medical center hospitals and a veterans' administration hospital over a cumulative 16-year period. Billing records provided information about where the code was assigned, whether it was a major or minor diagnosis, and if the code was assigned on multiple occasions for each patient. Histology and endoscopy records were reviewed to confirm the diagnosis of Barrett's esophagus. Among 435 patients with code 530.2 in their records, 354 (82%) had an esophageal biopsy reported and 393 (90%) had an endoscopy report available for review. Only 182 (42%) had specialized intestinal metaplasia documented in a biopsy from an area of salmon-colored mucosa arising above the esophagogastric junction (51% of those with histology available). There were 288 patients (66%) with an endoscopic diagnosis of Barrett's esophagus (73% of those with an endoscopy reported). Variables associated with documented specialized intestinal metaplasia were age ≥ 60 (OR 2.3; 95% CI 1.4–3.7), multiple assignments of 530.2 (OR 3.2; 95% CI 2.0–5.0), and assignment of 530.2 in a gastrointestinal (GI) clinic or an endoscopy unit (OR 3.5; 95% CI 2.0–6.3). The positive predictive value of the code being assigned in a GI location was 48% (95% CI 43–54%). Therefore, ICD-9-CM code of 530.2 is not specific for the diagnosis of Barrett's esophagus. The usage of code 530.2 in a GI setting was not sufficiently predictive of BE to be reliable for rigorous epidemiological studies.     

Comprehensive esophageal microscopy by using optical frequency-domain imaging (with video)

BACKGROUND: Optical coherence tomography (OCT) has been used for high-resolution endoscopic imaging and diagnosis of specialized intestinal metaplasia, dysplasia, and intramucosal carcinoma of the esophagus. However, the relatively slow image-acquisition rate of the present OCT systems inhibits wide-field imaging and limits the clinical utility of OCT for diagnostic imaging in patients with Barrett's esophagus. OBJECTIVE: This study describes a new optical imaging technology, optical frequency-domain imaging (OFDI), derived from OCT, that enables comprehensive imaging of large esophageal segments with microscopic resolution. DESIGN: A prototype OFDI system was developed for endoscopic imaging. The system was used in combination with a balloon-centering catheter to comprehensively image the distal esophagus in swine. RESULTS: Volumetric images of the mucosa and portions of the muscularis propria were obtained for 4.5-cm-long segments. Image resolution was 7 microm in depth and 30 microm parallel to the lumen, and provided clear delineation of each mucosal layer. The 3-dimensional data sets were used to create cross-sectional microscopic images, as well as vascular maps of the esophagus. Submucosal vessels and capillaries were visualized by using Doppler-flow processing. CONCLUSIONS: Comprehensive microscopic imaging of the distal esophagus in vivo by using OFDI is feasible. The unique capabilities of this technology for obtaining detailed information of tissue microstructure over large mucosal areas may open up new possibilities for improving the management of patients with Barrett's esophagus.     

Endoscopic Doppler optical coherence tomography in the human GI tract: initial experience

BACKGROUND: Expanding the current endoscopic optical coherence tomography (OCT) system with Doppler capability may augment this novel high-resolution cross-sectional imaging technique with functional blood flow information. The aim of this feasibility study was to assess the clinical feasibility of an endoscopic Doppler OCT (EDOCT) system in the human GI tract. METHODS: During routine endoscopy, 22 patients were imaged by using a prototype EDOCT system, which provided color-Doppler and velocity-variance images of mucosal and submucosal blood flow at one frame per second, simultaneously with high-spatial-resolution (10-25 mum) images of tissue microstructure. The images were acquired from normal GI tract and pathologic tissues. OBSERVATIONS: Subsurface microstructure and microcirculation images of normal and pathologic GI tissues, including Barrett's esophagus, esophageal varices, portal hypertensive gastropathy, gastric antral vascular ectasia, gastric lymphoma, and duodenal adenocarcinoma, were obtained from 72 individual sites in vivo. Differences in vessel diameter, distribution, density, and blood-flow velocity were observed among the GI tissue pathologies imaged. CONCLUSIONS: To our knowledge, this is the first study to demonstrate the feasibility of EDOCT imaging in the human GI tract during routine endoscopy procedures. EDOCT may detect the different microcirculation patterns exhibited by normal and diseased tissues, which may be useful for diagnostic imaging and treatment monitoring.     

Transepithelial leak in Barrett's esophagus patients: the role of proton pump inhibitors

AIM: To determine if the observed paracellular sucrose leak in Barrett’s esophagus patients is due to their proton pump inhibitor (PPI) use.METHODS: The in vivo sucrose permeability test was administered to healthy controls, to Barrett’s patients and to non-Barrett’s patients on continuous PPI therapy. Degree of leak was tested for correlation with presence of Barrett’s, use of PPIs, and length of Barrett’s segment and duration of PPI use.RESULTS: Barrett’s patients manifested a near 3-fold greater, upper gastrointestinal sucrose leak than healthy controls. A decrease of sucrose leak was observed in Barrett’s patients who ceased PPI use for 7 d. Although initial introduction of PPI use (in a PPI-naïve population) results in dramatic increase in sucrose leak, long-term, continuous PPI use manifested a slow spontaneous decline in leak. The sucrose leak observed in Barrett’s patients showed no correlation to the amount of Barrett’s tissue present in the esophagus.CONCLUSION: Although future research is needed to determine the degree of paracellular leak in actual Barrett’s mucosa, the relatively high degree of leak observed with in vivo sucrose permeability measurement of Barrett’s patients reflects their PPI use and not their Barrett’s tissue per se.     

食管胃连接处疾病的病因学和形态学研究现状

食管胃连接处（EGJ）系指食管与胃的交界,其组织学具有特殊性。贲门部是连接远端食管与胃底黏膜的区域,贲门是否存在及其真实长度仍存有争议。EGJ所涉及的疾病主要有贲门炎、反流性食管炎（RE）和Barrett食管（BE）,三者间存在一定的联系.