Confocal laser endomicroscopy in celiac disease: description of findings in two cases

High definition endoscopy with or without I-Scan increases the detection of celiac disease during routine endoscopy

BACKGROUND AND AIMS

Celiac disease remains underdiagnosed at endoscopy. We aimed to assess the utility of I-Scan (virtual chromo-endoscopy) to improve sensitivity of endoscopy to detect markers of villous atrophy in this condition.

METHODS

Patients from 2 UK hospitals were studied in 3 groups. Group 1: standard high definition, white light endoscopy (WLE); Group 2: WLE plus I-Scan; Group 3: non-high definition control group. The presence of endoscopic markers was recorded. At least 4 duodenal biopsies were taken from all patients. Serology was performed concurrently and observations were compared with histology.

RESULTS

758 patients (62% female, mean age 52) were recruited (Group 1: 230; Group 2: 228; Group 3: 300). 135 (17.8%) new diagnoses of coeliac disease were made (21 Group 1; 24 Group 2; 89 Group 3). The sensitivity for detection of endoscopic markers of villous atrophy was significantly higher in both Group 1 (85.7%, p=0.0004) and Group 2 (75%, p=0.005) compared to non-high definition controls (41.6%). There was no significant difference between high definition only and I-Scan groups (p=0.47). In non-high definition endoscopy a missed diagnosis was associated with lesser degrees of villous atrophy (p=0.019) and low tTG titre (p=0.007).

CONCLUSIONS

High definition endoscopy with or without I-Scan increases the detection of celiac disease during routine endoscopy.

Endoscopic tools for the diagnosis and evaluation of celiac disease

Celiac disease (CD) is an autoimmune disease of the small bowel induced by ingestion of wheat, rye and barley. Current guidelines indicate histological analysis on at least four duodenal biopsies as the only way to diagnose CD. These indications are based on the conception of the inability of standard endoscopy to make diagnosis of CD and/or to drive biopsy sampling. Over the last years, technology development of endoscopic devices has greatly ameliorated the accuracy of macroscopic evaluation of duodenal villous pattern, increasing the diagnostic power of endoscopy of CD. The aim of this paper is to review the new endoscopic tools and procedures proved to be useful in the diagnosis of CD, such as chromoendoscopy, Fujinon Intelligent Chromo Endoscopy, Narrow Band Imaging, Optical Coherence Tomography, Water-Immersion Technique, confocal laser endomicroscopy, high-resolution magnification endoscopy, capsule endoscopy and I-Scan technology.

Probe-Based Confocal Laser Endomicroscopy to Guide Real-Time Endoscopic Therapy in Barrett's Esophagus with Dysplasia

Probe-based confocal laser endomicroscopy (pCLE) is a novel imaging technique which utilizes a low-power laser light passed through a fiber-optic bundle, within a miniprobe that is advanced into the working channel, to obtain microscopic images of the mucosa. This allows the endoscopist to evaluate the microarchitecture of the gastrointestinal epithelium in real time. At this time pCLE cannot replace histopathology, but it can provide diagnostic information as well as guide therapeutic management in patients with Barrett's esophagus (BE) with high-grade dysplasia (HGD). We describe a retrospective case series in which four patients with BE and biopsy-proven HGD underwent endoscopy with pCLE to direct real-time endoscopic ablation therapy and/or endoscopic mucosal resection (EMR), which was performed in conjunction with pCLE. All four patients had pCLE showing features of HGD. After either EMR or radiofrequency ablation (RFA), pCLE was again used to evaluate the margins after therapy to assure accuracy. In one case, pCLE had features of dysplasia at the margin and further repeat EMR was immediately performed. Another case had a normal-appearing esophagus, but pCLE found features of BE in discrete areas and targeted biopsies were performed, which confirmed BE. This patient subsequently underwent RFA therapy of the residual areas of BE. In conclusion, in patients with BE and dysplasia, pCLE is an effective tool used to target biopsies, guide endoscopic therapy and assess the accuracy of EMR or RFA.

Probe-based confocal laser microscopy identifies criteria predictive of active celiac sprue

BACKGROUND

Celiac sprue is an underdiagnosed chronic intestinal inflammatory disease. Probe-based confocal laser microscopy (CLM) is a novel endoscopic technique for in vivo inspection of the intestinal mucosa that has not been evaluated in celiac sprue yet.

AIMS

To develop CLM criteria most predictive of celiac pathology in a prospective pilot study.

METHODS

Twenty-one patients (male n = 5, f = 16, mean age 52 years) with established or suspected celiac sprue, seven of whom had confirmed active disease (Marsh III) and 14 duodenal normal mucosa. CLM images from 91 duodenal sites were assessed. CLM recordings were obtained next to Argon beamer labeled areas. Biopsies were taken from the same spots for precise histological matching. After establishing histology-correlated criteria on one sample per patient, the remaining CLM recordings from the same patients were randomized and blindly evaluated.

RESULTS

Villous atrophy and irregular appearing villi were most predictive of celiac pathology. Although the presence of crypts was diagnostic for celiac pathology, it was only recognized in 26.7% of celiac pathology sites. Using these criteria in the blinded assessment, the overall endoscopist's prediction of celiac sprue was accurate in 89.8% of all biopsy sites in 85.7% of all patients. Preliminary interobserver agreement testing villous atrophy, irregular villi, and crypts was poor (kappa 0.05 to 0.26).

CONCLUSIONS

Probe-based CLM criteria developed in this pilot trial appear promising for the detection of active celiac sprue. Preliminary interobserver variability was high, indicating a learning curve effect. Our criteria need validation in an independent patient population.

Confocal endomicroscopy: instrumentation and medical applications

Advances in fiber optic technology and miniaturized optics and mechanics have propelled confocal endomicroscopy into the clinical realm. This high resolution, non-invasive imaging technology provides the ability to microscopically evaluate cellular and sub-cellular features in tissue in vivo by optical sectioning. Because many cancers originate in epithelial tissues accessible by endoscopes, confocal endomicroscopy has been explored to detect regions of possible neoplasia at an earlier stage by imaging morphological features in vivo that are significant in histopathologic evaluation. This technique allows real-time assessment of tissue which may improve diagnostic yield by guiding biopsy. Research and development continues to reduce the overall size of the imaging probe, increase the image acquisition speed, and improve resolution and field of view of confocal endomicroscopes. Technical advances will continue to enable application to less accessible organs and more complex systems in the body. Lateral and axial resolutions down to 0.5 and 3 μm, respectively, field of view as large as 800 × 450 μm, and objective lens and total probe outer diameters down to 0.35 and 1.25 mm, respectively, have been achieved. We provide a review of the historical developments of confocal imaging in vivo, the evolution of endomicroscope instrumentation, and the medical applications of confocal endomicroscopy.

Exploring the optimal fluorescein dose in probe-based confocal laser endomicroscopy for colonic imaging

BACKGROUND: Probe-based confocal laser endomicroscopy (pCLE) is an emerging method for in-vivo imaging of the gastrointestinal tract and requires a contrast agent. Fluorescein is the most commonly used agent. The optimal dose of fluorescein for pCLE in colon is unknown. OBJECTIVE: Exploration of optimal dose of fluorescein for pCLE in colon. DESIGN: Comparative, prospective pilot trail. SETTING: Tertiary-care center. PATIENTS: 18 participants underwent colonoscopy without complications. INTERVENTIONS: pCLE videos were recorded in normal cecum, using 10% fluorescein intravenously. MAIN OUTCOME MEASUREMENTS: For subjective analysis, pCLE videos were scored for quality, by 2 observers, independently and blinded to fluorescein dose. For objective analysis, signal-to-noise ratios (SNR) were calculated for each video by an expert. RESULTS: 6 fluorescein doses were used, including 0.5 mL, 1 mL, 2.5 mL, 5 mL, 7.5 mL and 10 mL and each dose was used in three patients. For each dose, median image quality score was 2.5, 2.0, 3.25, 4.0, 4.0 and 3.5 by first observer and 2.0, 3.0, 4.0, 5.0, 4.0 and 4.0 by second observer, respectively. The subjective quality scores increased from 0.5 mL to 5.0 mL, with no evidence of further improved quality at 7.5 mL and 10 mL doses. SNR were not significantly different between doses but trended higher for higher doses. LIMITATIONS: Small sample size. The results can not be applied to other parts of gastrointestinal tract i.e. duodenum, esophagus with different blood supply. CONCLUSION: This preliminary study suggests that the optimal dose of fluorescein for high quality pCLE imaging in colon is approximately 5.0 mL.

Spectral endoscopic imaging: the multiband system for enhancing the endoscopic surface visualization

In the past few years, newly developed procedures and technologies have improved endoscopic recognition of the gastrointestinal tract. In particular, narrow band imaging, multiband imaging, and contrast enhancement make possible the "real-time," on demand recognition of the gastrointestinal mucosa during the endoscopic examination. These imaging techniques have been designed to enhance visualization of the vascular network and surface texture of the mucosa in an effort to improve tissue characterization, differentiation, and diagnosis. These techniques are considered as potential alternatives to chromoendoscopy because they provide contrast enhancement of tissue surface structures. This review focuses on data published on multiband imaging system. We report the technological basis of the system and speculate on its applications. Therefore, PubMed was searched for articles published up to 31 October 2009 using, in combination, these terms: "multiband imaging," "band imaging," "endoscopy," "high-resolution," "gastrointestinal," "FICE," "magnification," "spectral endoscopic images," "computed virtual chromoendoscopy." The reference list of articles identified in the initial PubMed search was reviewed for further relevant publications. Abstracts of communications presented to the most relevant international meetings and congresses were also included in this review. We did not carry out meta-analyses and reviewed only articles published in English.

Role of confocal endomicroscopy in the diagnosis of celiac disease

BACKGROUND AND AIMS

Confocal laser endomicroscopy (CLE) is a recent development that enables surface and subsurface imaging of living cells in vivo at 1000 x magnification. The aims of the present study were to define confocal features of celiac disease (CD) and to evaluate the usefulness of the CLE in the diagnosis of CD in children in comparison to histology.

PATIENTS AND METHODS

Nine patients (8 girls) with a median age of 8.35 years (range 2-12.66 years) and a median weight of 28.3 kg (range 11-71 kg) were suspected with CD and 10 matched controls underwent oesophagogastroduodenoscopy using the confocal laser endomicroscope (EC3870CILK; Pentax, Tokyo, Japan). Histologic sections were compared with the confocal images of the same site by 2 experienced paediatric histopathologists and endoscopists, all of whom were blinded to the diagnosis.

RESULTS

The median procedure time was 17 minutes (range 8-25 minutes). Confocal features of CD were defined and a score was developed. A total of 1384 confocal images were collected from 9 patients and 10 controls. Five images from each patient and control were selected and compared with the biopsy specimen of the same site. The sensitivity, specificity, and positive predictive value for the confocal images in comparison to the histology were 100%, 80%, and 81%. The kappa inter-observer agreement between the 2 endoscopists was 0.769 (P = 0.018) and between the 2 histopathologists was 0.571 (P = 0.05).

CONCLUSIONS

Confocal endomicroscopy offers the prospect of diagnosis of CD during ongoing endoscopy. It also enables targeting biopsies to abnormal mucosa and thereby increasing the diagnostic yield, especially when villous atrophy is patchy in the duodenum.

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.

Endocytoscopy for the detection of microstructural features in adult patients with celiac sprue: a prospective, blinded endocytoscopy-conventional histology correlation study

BACKGROUND

Endocytoscopy (EC) is a novel technique that allows magnified live inspection of the intestinal mucosa.

OBJECTIVE

To evaluate EC for the detection of key pathological findings in patients with celiac sprue.

DESIGN

A total of 166 EC recordings were prospectively acquired. Matched videos, images, and biopsy specimens were obtained by duodenal argon beamer labeling of the respective sites.

SETTING

Academic tertiary referral center.

PATIENTS

Forty patients (mean age 51.5 years, 70% women) with established (n = 32) or suspected (n = 8) celiac disease (CD).

INTERVENTIONS

A validated scoring system (Marsh classification) was used to assess disease activity. EC criteria were independently evaluated by 2 gastroenterologists and 1 pathologist.

MAIN OUTCOME MEASUREMENTS

The primary endpoint was to examine EC correlation with conventional CD histology.

RESULTS

Of 166 duodenal biopsy sites, 23% were classified as Marsh III (moderate to severe), 10% as Marsh I (mild), and 67% as Marsh 0 (normal). Using the 450x magnification, we found that identification of crypts was diagnostic for celiac pathology. Four criteria were significant predictors of Marsh III pathology when adjusted by multivariate analysis: low number of villi per visual field (<3; odds ratio [OR] 9.1; 95% CI, 1.3-62.0), confluence of villi (OR 37.1; 95% CI, 1.3-1021.2), irregular epithelial lining (OR 10.9; 95% CI, 2.5-46.7), and inability to delineate loop capillaries (OR 14.9; 95% CI, 3.3-67.0). None was a good predictor of Marsh I pathology.

LIMITATIONS

Single-center experience. No prospective validation of the criteria in an independent patient population.

CONCLUSIONS

EC at 450x magnification accurately identifies mucosal histopathology of advanced CD, but not early morphological changes.

Advances in confocal laser endomicroscopy for the diagnosis of gastrointestinal diseases

BACKGROUND

Confocal laser endomicroscopy (CLE) is a novel technique enabling in vivo microscopy of the human gastrointestinal mucosa. Cellular details even below the tissue surface can be visualized at high resolution during ongoing endoscopy.

OBJECTIVE

This review summarizes the current clinical data on the use of CLE in different disease states and discusses a perspective for future clinical and scientific application of CLE.

METHODS

Review on published literature and meeting abstracts.

RESULTS/CONCLUSION

Confocal laser endomicroscopy covers a growing field of indications in both upper and lower gastrointestinal endoscopy and beyond. It has been shown to reliably predict the presence of neoplastic lesions and inflammatory changes of the gastrointestinal mucosa during endoscopy. With CLE, 'smart' biopsies can be targeted to regions with microscopic alterations rather than having to rely on blind, untargeted sampling. This results in a reduction in the number of biopsies and in an increase in their diagnostic yield at the same time. Dynamic imaging of microscopic events in their natural environment and molecular imaging by CLE will open a door for an advanced understanding of tissue function and microarchitecture in vivo.

Confocal laser endomicroscopy for the detection of mucosal changes in ileal pouch after restorative proctocolectomy

BACKGROUND

Pouchitis and dysplasia may affect the reservoir after restorative proctocolectomy.

AIMS

To assess the suitability of confocal laser endomicroscopy for the in vivo diagnosis of mucosal changes in ileal pouch for ulcerative colitis and familial adenomatous polyposis.

METHODS

Standard endoscopy and endomicroscopy were performed in 18 pouches. Confocal images were scored for the presence of villous atrophy, inflammation, ulceration, colonic metaplasia and dysplasia. Targeted biopsies were taken. Endomicroscopic and histological findings were compared.

RESULTS

At standard endoscopy, the signs of pouchitis were recorded in 7/18 (38.9%) patients. At endomicroscopy, pathological features were found in 16/18 (88.9%), villous atrophy in 15/18 (83.3%), inflammation in 13/18 (72.2%), ulceration in 3/18 (16.7%), and colonic metaplasia in 12/18 (67.7%). No dysplasia was observed. At histology, abnormalities were present in 17/18 (94.4%): villous atrophy in 15/18 (83.3%), inflammation in 17/18 (94.4%), ulceration in 6/18 (33.3%), colonic metaplasia in 15/18 (83.3%). Morphological changes of the ileal pouch could be predicted with an accuracy of 94.4% (95% CI: 74.2-99.0). The k-value for intra- and interobserver agreement was 0.93 and 0.78, respectively.

CONCLUSIONS

Endomicroscopy may be helpful in the evaluation of morphologic changes in ileal pouch. The small size of the population sample requires further studies for the results to be confirmed.

In vivo confocal endomicroscopy in the diagnosis and evaluation of celiac disease

BACKGROUND & AIMS

Accurate histopathology of endoscopic duodenal biopsy specimens is critical in the diagnosis of celiac disease (CD) but sampling error and poor quality specimens may generate a false-negative result. Confocal endomicroscopy (CEM) is a novel technology allowing real-time in vivo microscopy of the mucosa that may diagnose CD and evaluate its severity and response to treatment more accurately than histopathology.

METHODS

Subjects with CD and controls prospectively underwent CEM. Features of villous atrophy and crypt hypertrophy were defined. A CEM score measuring CD severity was devised and validated against the diagnosis of CD and blinded histopathology. Receiver operator characteristics, sensitivity to change after treatment, and reliability of findings were assessed.

RESULTS

From 31 patients (6 untreated CD, 11 treated CD, and 14 controls), 7019 CEM images paired with 326 biopsy specimens were obtained. The accuracy of CEM in diagnosing CD was excellent (receiver operator characteristics area under the curve, 0.946; sensitivity, 94%, specificity, 92%) and correlated well with the Marsh grading (R-squared, 0.756). CEM differentiated CD from controls (P < .0001) and was sensitive to change after treatment with gluten-free diet (1787 optical biopsies; P = .012). The intraclass correlation of reliability was high (0.759-0.916). Of the 17 cases with diagnosed CD, 16 (94%) were diagnosed correctly using CEM but only 13 (76%) had detectable histopathology changes. The procedure was safe and well-tolerated.

CONCLUSIONS

CEM effectively diagnoses and evaluates CD severity in vivo. This promising technique has the potential to improve endoscopy efficiency.

Emerging technologies in upper gastrointestinal endoscopy and celiac disease

Despite advances in our knowledge of celiac disease, the most current and authoritative recommendations conclude that diagnosis requires at least four biopsy specimens to be taken from the duodenal area. These recommendations are based on the perception that classic endoscopic markers are not adequate to target biopsy sampling to sites of villous damage in the duodenum. In the past few years, newly developed procedures and technologies have improved endoscopic recognition of the duodenum. These advances make possible the real-time recognition of the duodenal villous pattern during an upper endoscopy procedure, and thereby have the potential to optimize diagnostic accuracy. It is, therefore, reasonable to hypothesize that upper endoscopy might have a more incisive role in the diagnosis of celiac disease than merely providing a means of obtaining biopsy specimens for histological analysis. This Review highlights the new technologies in the field of upper endoscopy that could be helpful for the diagnosis of celiac disease, including the water-immersion technique, chromoendoscopy, high-resolution magnification endoscopy, optimal band imaging, optical coherence tomography and confocal endomicroscopy.

Systematic review: The evidence base for long-term management of coeliac disease

BACKGROUND

While gluten-free diet is an effective treatment for coeliac disease, the need for and goals of long-term management of patients are poorly defined.

AIM

To review systematically the complications and associations of coeliac disease, to identify potential risk factors, to define ways of assessing risk factors and to provide a strategy for management.

METHODS

Review of medical literature from 1975.

RESULTS

There is an increasing list of potential complications and/or conditions associated with coeliac disease, in particular, autoimmune disease, malignancy and bone disease. Risk factors that may predict or influence long-term outcomes include genetic susceptibility, environmental factors predominantly gluten ingestion, persistent small intestinal inflammation/injury and nutritional deficiencies. Genotyping of patients is yet to have an established clinical role in long-term management. Assessment of adherence to the gluten-free diet largely relies upon skilled dietary history, but the ultimate test is duodenal histopathology, which is the only currently established means of assessing healing. Symptoms, serology or other non-invasive means are poor predictors of healing and the likelihood of complications.

CONCLUSION

Evidence (albeit limited) that adherence to a gluten-free diet and mucosal healing prevent and/or ameliorate complications indicates that a planned long-term strategy for follow-up is essential.

Current application of confocal endomicroscopy in gastrointestinal disorders

Confocal endomicroscopy (CEM) is a recent advancement in imaging technology that incorporates a confocal laser microscope into the tip of a flexible endoscope. The 1000-fold magnification and high resolution allows for real time in vivo histology or "virtual biopsies" of the gastrointestinal tract mucosa. CEM has the capability to instantaneously diagnose intra-epithelial neoplasia during endoscopy, alone or in combination with a "red-flag" technique, such as chromoendoscopy. Therefore, there is clinical utility in the surveillance or diagnosis of Barrett's esophagus, gastric intestinal metaplasia and cancer, longstanding ulcerative colitis, and colonic neoplasia. Furthermore, CEM also appears to be useful in the evaluation of coeliac disease, microscopic colitis, and in diagnosing Helicobacter pylori chronic gastritis. This review examines the current available data on the utility of this new technology in clinical gastroenterology and its potential impact in the future.

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.

Confocal endomicroscopy

PURPOSE OF REVIEW

Confocal laser endomicroscopy is an emerging field of endoscopic imaging allowing gastroenterologists to obtain in-vivo histology of the gastrointestinal mucosa. The present review will address the more recent advances in confocal laser endomicroscopy and discuss its future.

RECENT FINDINGS

Interest in confocal laser endomicroscopy and in-vivo diagnosis of gastrointestinal disorders has increased in the last few years. Confocal laser endomicroscopy can localize intraepithelial neoplasia in chronic ulcerative colitis and enable 'smarter' mucosal biopsy when combined with chromoendoscopy. Confocal laser endomicroscopy may accurately diagnose neoplasia in the esophagus, stomach, colon, and bile duct. Moreover, in-vivo visualization of morphologic epithelial abnormalities, such as intraepithelial bacteria and 'gaps in the gut', may increase our understanding of the possible pathogenic mechanisms of disease. Fluorescent peptide markers that target neoplasia are also being developed as a complementary approach to visualization of in-vivo histopathology.

SUMMARY

Confocal endomicroscopy is a developing area of gastrointestinal endoscopy with expanding clinical and research applications. The present review focuses on recent advances in confocal endomicroscopy.

Confocal laser endomicroscopy for gastrointestinal diseases

Confocal laser endomicroscopy enables in vivo microscopy of the mucosal layer of the gastrointestinal tract with subcellular resolution during ongoing endoscopy. Endomicroscopy opens the door to 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, and subsurface imaging can unmask microscopic diseases or bacterial infection. Molecular imaging is becoming feasible, which will enable new indications in gastrointestinal endoscopy. This article reviews the current and rapidly expanding clinical data on endomicroscopy and gives a look into future research.