Validation of a new optical diagnosis training module to improve dysplasia characterization in inflammatory bowel disease: a multicenter international study

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) increases risk of dysplasia and colorectal cancer. Advanced endoscopic techniques allow for the detection and characterization of IBD dysplastic lesions, but specialized training is not widely available. We aimed to develop and validate an online training platform to improve the detection and characterization of colonic lesions in IBD: OPtical diagnosis Training to Improve dysplasia Characterization in Inflammatory Bowel Disease (OPTIC-IBD).

METHODS

We designed a web-based learning module that includes surveillance principles, optical diagnostic methods, approach to characterization, and classifications of colonic lesions using still images and videos. We invited gastroenterologists from Canada, Italy, and the United Kingdom with a wide range of experience. Participants reviewed 24 educational videos of IBD colonic lesions, predicted histology, and rated their confidence. The primary endpoint was to improve accuracy in detecting dysplastic lesions after training on the platform. Furthermore, participants were randomized 1:1 to get additional training or not, with a final assessment occurring after 60 days. Diagnostic performance for dysplasia and rater confidence were measured.

RESULTS

A total of 117 participants completed the study and were assessed for the primary endpoint. Diagnostic accuracy improved from 70.8% to 75.0% (P = .002) after training, with the greatest improvements seen in less experienced endoscopists. Improvements in both accuracy and confidence were sustained after 2 months of assessment, although the group randomized to receive additional training did not improve further. Similarly, participants' confidence in characterizing lesions significantly improved between before and after the course (P < .001), and it was sustained after 2 months of assessment.

CONCLUSIONS

The OPTIC-IBD training module demonstrated that an online platform could improve participants' accuracy and confidence in the optical diagnosis of dysplasia in patients with IBD. The training platform can be widely available and improve endoscopic care for people with IBD. (Clinical trial registration number: NCT04924543.).

Dye-based chromoendoscopy for the detection of colorectal neoplasia: meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Dye-based chromoendoscopy (DBC) could be effective in increasing the adenoma detection rate (ADR) in patients undergoing colonoscopy, but the technique is time-consuming and its uptake is limited. We aimed to assess the effect of DBC on ADR based on available randomized controlled trials (RCTs).

METHODS

Four databases were searched up to April 2022 for RCTs comparing DBC with conventional colonoscopy (CC) in terms of ADR, advanced ADR, and sessile serrated adenoma detection rate as well as the mean adenomas per patient and non-neoplastic lesions. Relative risk (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes were calculated using random-effect models. The I² test was used for quantifying heterogeneity. Risk of bias was evaluated with the Cochrane tool.

RESULTS

Overall, 10 RCTs (5334 patients) were included. Indication for colonoscopy was screening or surveillance (3 studies) and mixed (7 studies). Pooled ADR was higher in the DBC group versus the CC group (95% CI, 48.1% [41.4%-54.8%] vs 39.3% [33.5%-46.4%]; RR, 1.20 [1.11-1.29]), with low heterogeneity (I² = 29%). This effect was consistent for advanced ADR (RR, 1.21 [1.03-1.42]; I² = .0%), sessile serrated adenomas (6.1% vs 3.5%; RR, 1.68 [1.15-2.47]; I² = 9.8%), and mean adenomas per patient (MD, .24 [.17-.31]) overall and in the right-sided colon (MD, .28 [.14-.43]). A subgroup analysis considering only trials using high-definition white-light endoscopy reduced the heterogeneity while still showing a significant increase in adenoma detection with DBC: 51.6% (95% confidence interval [CI], 47.1%-56.1%) and 59.1% (95% CI, 54.7-63.3%), RR = 1.14 (95% CI, 1.06-1.23), P = .0004, I² = .0%, P = .50.

CONCLUSIONS

Meta-analysis of RCTs showed that DBC increases key quality parameters in colonoscopy, supporting its use in everyday clinical practice.

[Catch me if you can: endoscopic remove of a needle from the jejunum]

INTRODUCTION

The ingestion of foreign bodies is a frequently observed problem in daily clinical practice. In order to avoid complications such as perforation, endoscopic removal of potentially penetrating foreign bodies should be attempted quickly. The use of various endoscopic techniques has been reported for this purpose. However, extraction of foreign bodies from the mid gastrointestinal tract has rarely been reported.

CASE REPORT

We present the case of a patient who had swallowed a safety needle which could safely be removed from the jejunum by means of double-balloon enteroscopy (DBE). The combination of a thin p-type enteroscope with a thick t-type overtube was used in order to improve the manoeuvrability of the endoscope. The needle was pulled into the overtube which served as a protective shield during the retrieval of the endoscope.

CONCLUSION

Our case report describes the potential of removing foreign bodies from the deep small bowel by pulling them into the overtube of a double-balloon enteroscope. If the suspicion of foreign body impaction in the small bowel is made, it may be advisable to primarily choose a balloon enteroscopy system. Through this, quick and deep insertion can be combined with a safe removal of the foreign body.

High-definition endoscopy with iScan and Lugol's solution for the detection of inflammation in patients with nonerosive reflux disease: histologic evaluation in comparison with a control group

Nonerosive reflux disease (NERD) is commonly diagnosed in patients with symptoms of reflux. The aim of the present study was to determine whether high-definition endoscopy (HD) plus equipped with the iScan function or chromoendoscopy with Lugol's solution might permit the differentiation of NERD patients from those without reflux symptoms, proven by targeted biopsies of endoscopic lesions. A total of 100 patients without regular intake of proton pump inhibitors and with a normal conventional upper endoscopy were prospectively divided into NERD patients and controls. A second upper endoscopy was performed using HD+ with additional iScan function and then Lugol's solution was applied. Biopsy specimens were taken from the gastroesophageal junction in all patients. A total of 65 patients with reflux symptoms and 27 controls were included. HD(+) endoscopy with iScan revealed subtle mucosal breaks in 52 patients; the subsequent biopsies confirmed esophagitis in all cases. After Lugol's solution, 58 patients showed mucosal breaks. Sensitivity for the iScan procedure was 82.5%, whereas that for Lugol's solution was 92.06%. Excellent positive predictive values of 100% and 98.3%, respectively, were noted. The present study suggests that the majority of patients with NERD and typical symptoms of reflux disease can be identified by iScan or Lugol's chromoendoscopy as minimal erosive reflux disease (ERD) patients.

[Incidental findings in gastroscopy and colonoscopy]

For many specific and nonspecific gastrointestinal symptoms, endoscopic diagnostic procedures play an important role. Gastroscopy and colonoscopy are easily available diagnostic and interventional procedures with low risk. The technical development of gastrointestinal endoscopy has led to an improvement in diagnostics and therapy. In addition to frequent and expected findings, incidental findings may occur. The incidental findings can distinguish rare diseases of unexpected diagnoses. Rare diagnoses usually require an individualized therapy. Unexpected diagnoses can take place during (not properly detected) or after an endoscopy (overlooked or newly appeared) occur. This overview deals with the question of how to minimize unexpected diagnoses and how to diagnose and treat incidental findings.

[Upper gastrointestinal bleeding and haemorrhagic shock at the end of the holidays: pre-hospital and in-hospital management of a gastrointestinal emergency]

Upon returning from holidays, a 55-year-old patient presenting with melena and haemorrhagic shock was admitted to a University hospital after receiving first emergency medical care in a German InterCity train. In an interdisciplinary effort, haemodynamics were stabilised and the airway and respiratory function were secured. Under emergency care conditions the patient then underwent an emergency upper GI endoscopy where a spurting arterial upper gastrointestinal bleeding (Forrest 1a) was found. While the bleeding could not be controlled with endoscopic techniques, definitive haemostasis was achieved with a surgical laparotomy. While not commonly established for patients with severe GI bleeding, by spontaneous implementation of an interdisciplinary trauma room approach following established trauma algorithms the team was able to achieve stabilisation of vital functions and final control of bleeding in this highly unstable patient. Although the majority of upper gastrointestinal bleedings spontaneously cease, emergency care algorithms should be developed and implemented for patients with severe gastrointestinal bleedings in shock. Following the case vignette, we discuss a potential approach and develop an exemplary protocol for shock room management in this patient subgroup.

In vivo molecular imaging with cetuximab, an anti-EGFR antibody, for prediction of response in xenograft models of human colorectal cancer

BACKGROUND AND STUDY AIMS

Molecular imaging has mainly been studied for detection of lesions using diagnostic probes. The aim of the current trial was to evaluate in vivo confocal laser endomicroscopy (CLE) with cetuximab, an antibody targeting the epidermal growth factor receptor (EGFR), for detection and moreover early prediction of response to molecular chemotherapy in models of human colorectal cancer (CRC).

METHODS

Xenografts with cetuximab-sensitive (HT29) and cetuximab-resistant (SW620) human CRC cell lines were induced in 44 mice. CLE was performed 48 h after injection of a fluorescently labelled cetuximab test dose, and compared with isotype antibody or untreated controls on d0, and d30 (HT29) or d15 (SW620). Initial fluorescence intensity was examined in relation to clinical readouts (tumor growth, thriving, mortality) during cetuximab treatment vs. controls. Results were validated in vivo with wide-field molecular imaging in three HT29 mice and ex vivo using fluorescence-activated cell sorting (FACS) and immunohistochemistry.

RESULTS

All HT29 xenografts showed specific fluorescence in vivo after cetuximab injection on d0 and d30. Fluorescence at d0 was significantly stronger in cetuximab-treated HT29 tumors than in HT29 controls (P = 0.0017) or cetuximab-treated SW620 tumors (P = 0.0027), and accorded with significantly slower tumor progression (P = 0.0009), better overall survival (P = 0.02), and better physical condition (P < 0.0001). Cetuximab sensitivity could be predicted from fluorescence intensity at d0 with high positive predictive value.

CONCLUSIONS

Molecular CLE was for the first time linked to early prediction of response to targeted therapy in models of human CRC. Therapeutic antibodies can be used as molecular beacons in CLE and wide-field techniques. These results may indicate a promising principle for early patient stratification.

Local barrier dysfunction identified by confocal laser endomicroscopy predicts relapse in inflammatory bowel disease

OBJECTIVES

Loss of intestinal barrier function plays an important role in the pathogenesis of inflammatory bowel disease (IBD). Shedding of intestinal epithelial cells is a potential cause of barrier loss during inflammation. The objectives of the study were (1) to determine whether cell shedding and barrier loss in humans can be detected by confocal endomicroscopy and (2) whether these parameters predict relapse of IBD.

METHODS

Confocal endomicroscopy was performed in IBD and control patients using intravenous fluorescein to determine the relationship between cell shedding and local barrier dysfunction. A grading system based on appearances at confocal endomicroscopy in humans was devised and used to predict relapse in a prospective pilot study of 47 patients with ulcerative colitis and 11 patients with Crohn's disease.

RESULTS

Confocal endomicroscopy in humans detected shedding epithelial cells and local barrier defects as plumes of fluorescein effluxing through the epithelium. Mouse experiments demonstrated inward flow through some leakage-associated shedding events, which was increased when luminal osmolarity was decreased. In IBD patients in clinical remission, increased cell shedding with fluorescein leakage was associated with subsequent relapse within 12 months after endomicroscopic examination (p<0.001). The sensitivity, specificity and accuracy for the grading system to predict a flare were 62.5% (95% CI 40.8% to 80.4%), 91.2% (95% CI 75.2 to 97.7) and 79% (95% CI 57.7 to 95.5), respectively.

CONCLUSIONS

Cell shedding and barrier loss detected by confocal endomicroscopy predicts relapse of IBD and has potential as a diagnostic tool for the management of the disease.

MedJet--a new CO2-based disposable cleaning device allows safe and effective bowel cleansing during colonoscopy: a pilot study

BACKGROUND AND STUDY AIMS

Complete bowel cleansing is mandatory for effective colon cancer screening and surveillance. The aim of the current pilot study, which was conducted in humans, was to test the safety and efficiency of a newly developed disposable cleaning device, the MedJet, for intraprocedural bowel cleansing.

PATIENTS AND METHODS

Patients with screening or surveillance colonoscopy after previous polypectomy were included. The colonoscope was first inserted to the cecum and the overall cleansing was assessed according to the Ottawa scale. The MedJet device was used if colon cleansing had been incomplete. The MedJet catheter was passed over the working channel of the colonoscope and the colon was cleaned during withdrawal. The MedJet device delivered controlled jets comprising compressed CO2 and minimal amounts of sterile water, which allowed disintegration and removal of residual stool. The efficiency of cleaning was assessed according to the Boston scale.

RESULTS

A total of 32 patients (16 female; mean age 61 years) were treated with the device. No device-related adverse or serious adverse events were noted. MedJet application during withdrawal provided effective and significant improvement in bowel cleansing (P = 0.005). Furthermore, 18 adenomas and 1 colon cancer, which were hidden behind stool remnants, could be identified in 11 patients following use of the MedJet device. However, the withdrawal times were prolonged (11.4±6.0 minutes) due to the additional cleaning procedure. All patients tolerated the procedure well.

CONCLUSIONS

The new MedJet device enabled highly effective and safe bowel cleansing during colonoscopy. The catheter-based system was easy to use and CO2 was applied for cleansing. The procedure was well tolerated by patients.

Review article: in vivo imaging by endocytoscopy

BACKGROUND

Endocytoscopy (EC) enables in vivo microscopic imaging at 1400-fold magnification, thereby allowing the analysis of mucosal structures at the cellular level. In contrast to fluorescence imaging with confocal laser endomicroscopy which allows analysis of mucosal structures up to 250 μm in depth, EC is based on the principle of contact light microscopy and only allows visualisation of the very superficial mucosal layer.

AIM

To systematically review the feasibility and diagnostic yield of EC for in vivo diagnosis of diseases.

METHODS

A systematic search of the literature on diagnostic interventions in the gastrointestinal tract using EC was performed by searches in MEDLINE, Current Contents, PubMed, cross-references and references from relevant articles using the search terms 'endocytoscopy', 'endocytoscope', 'magnification endoscopy', 'endocytoscopic imaging', 'virtual histology' and 'optical biopsy'. Only full manuscripts and case reports published in English were included.

RESULTS

Overall twenty-nine relevant reports were identified. EC was feasible to detect oesophageal squamous cell cancer with sensitivity, specificity and accuracy of 95%, 84% and 82%, respectively. Moreover, EC reached excellent sensitivity and specificity for in vivo diagnosis of colon polyps (91% and 100%, respectively). Other diagnostic applications of EC included diagnosis of Barrett's oesophagus, Helicobacter pylori, coeliac disease and small cell lung cancer. No serious complications of EC have yet been reported.

CONCLUSIONS

Endocytoscopy is a safe and effective new endoscopic imaging technique to obtain in vivo histology and guided biopsies with high diagnostic accuracy. Therefore, endocytoscopy has the potential to facilitate both diagnosis and patient management.

High definition colonoscopy combined with i-Scan is superior in the detection of colorectal neoplasias compared with standard video colonoscopy: a prospective randomized controlled trial

INTRODUCTION

Colonoscopy is the accepted gold standard for the detection of colorectal cancer. The aim of the current study was to prospectively compare high definition plus (HD+) colonoscopy with I-Scan functionality (electronic staining) vs. standard video colonoscopy. The primary endpoint was the detection of patients having colon cancer or at least one adenoma.

METHODS

A total of 220 patients due to undergo screening colonoscopy, postpolypectomy surveillance or with a positive occult blood test were randomized in a 1 : 1 ratio to undergo HD+ colonoscopy in conjunction with I-Scan surface enhancement (90i series, Pentax, Tokyo, Japan) or standard video colonoscopy (EC-3870FZK, Pentax). Detected colorectal lesions were judged according to type, location, and size. Lesions were characterized in the HD+ group by using further I-Scan functionality (p- and v-modes) to analyze pattern and vessel architecture. Histology was predicted and biopsies or resections were performed on all identified lesions.

RESULTS

HD+ colonoscopy with I-Scan functionality detected significantly more patients with colorectal neoplasia (38 %) compared with standard resolution endoscopy (13 %) (200 patients finally analyzed; 100 per arm). Significantly more neoplastic (adenomatous and cancerous) lesions and more flat adenomas could be detected using high definition endoscopy with surface enhancement. Final histology could be predicted with high accuracy (98.6 %) within the HD+ group.

CONCLUSIONS

HD+ colonoscopy with I-Scan is superior to standard video colonoscopy in detecting patients with colorectal neoplasia based on this prospective, randomized, controlled trial.

In vivo molecular imaging of somatostatin receptors in pancreatic islet cells and neuroendocrine tumors by miniaturized confocal laser-scanning fluorescence microscopy

The aim of the study was to evaluate real time in vivo molecular imaging of somatostatin receptors (sstrs) using a handheld miniaturized confocal laser scan microscope (CLM) in conjunction with fluorescein-labeled octreotate (OcF) in healthy mice and murine models of neuroendocrine tumors. For CLM a small rigid probe (diameter 7 mm) with an integrated single line laser (488 nm) was used (optical slice thickness 7 mum; lateral resolution 0.7 mum). OcF was synthesized via Fmoc solid-phase peptide synthesis and purified by HPLC showing high-affinity binding to the sstr2 (IC(50) 6.2 nmol). For in vitro evaluation, rat and human pancreatic cancer cells were used and characterized with respect to its sstr subtype expression and functional properties. For in vivo confocal imaging, healthy mouse pancreatic islet and renal tubular cells as well as immunoincompetent nude mice harboring sstr-expressing tumors were evaluated. Incubation of sstr-positive cells with OcF showed a specific time- and dose-dependent staining of sstr-positive cells. CLM showed rapid internalization and homogenous cytoplasmatic distribution. After systemic application to mice (n = 8), specific time-dependent internalization and cytoplasmatic distribution into pancreatic islet cells and tubular cells of the renal cortex was recorded. After injection in tumor-harboring nude mice (n = 8), sstr-positive cells selectively displayed a cell surface and cytoplasmatic staining. CLM-targeted biopsies detected sstr-positive tumor cells with a sensitivity of 87.5% and a specificity of 100% as correlated with ex vivo immunohistochemistry. CLM with OcF permits real-time molecular, functional, and morphological imaging of sstr-expressing cell structures, allowing the specific visualization of pancreatic islet cells and neuroendocrine tumors in vivo.

[Molecular imaging of the small intestine]

Molecular imaging uses the molecular signature of cells for targeted minimally-invasive detection and characterization of gastrointestinal pathologies. Exogenous fluorescent agents serve as molecular beacons for visualization of specific surface markers or metabolic activity in the target tissue. Molecular imaging with radioactively labeled substances is well established in nuclear medicine for wide-field detection of lesions in the small intestine. In gastrointestinal endoscopy, both macroscopic detection by endogenous or exogenous fluorescence and microscopic visualization by endomicroscopy have been investigated in clinical trials, however have not yet been evaluated in larger patient cohorts. Still, molecular imaging has the potential to greatly enhance our understanding of gastrointestinal pathology and to impact on future clinical algorithms and science in gastroenterology.

The safety of intravenous fluorescein for confocal laser endomicroscopy in the gastrointestinal tract

BACKGROUND

Confocal laser endomicroscopy (CLE) is rapidly emerging as a valuable tool for gastrointestinal endoscopic imaging. Fluorescent contrast agents are used to optimize imaging with CLE, and intravenous fluorescein is the most widely used contrast agent. Fluorescein is FDA-cleared for diagnostic angiography of the retina. For these indications, the safety profile of fluorescein has been well-documented; however, to date, fluorescein is not cleared for use with CLE.

AIMS

To estimate the rate of serious and total adverse events attributable to intravenous fluorescein when used for gastrointestinal CLE.

METHODS

We performed a cross sectional survey of 16 International Academic Medical Centres with active research protocols in CLE that involved intravenous fluorescein. Centres using i.v. fluorescein for CLE who were actively monitored for adverse events were included.

RESULTS

Sixteen centres performed 2272 gastrointestinal CLE procedures. The most common dose of contrast agent was 2.5-5 mL of 10% sodium fluorescein. No serious adverse events were reported. Mild adverse events occurred in 1.4% of individuals, including nausea/vomiting, transient hypotension without shock, injection site erythema, diffuse rash and mild epigastric pain. The limitation is that only immediate post procedure events were actively monitored.

CONCLUSIONS

Use of intravenous fluorescein for gastrointestinal CLE appears to be safe with few acute complications.

Recognition and characterization of small colonic neoplasia with high-definition colonoscopy using i-Scan is as precise as chromoendoscopy

BACKGROUND

The EPKi system (Pentax, Japan) enables resolution above HDTV. Aim of the study was to test the efficacy of HD+ alone and with the new post-processing digital filter i-Scan or chromoendoscopy (Methylene blue 0.1%) in screening for colorectal cancer. We focused on lesions less than 5 mm as a surrogate marker for the optical possibilities of the EPKi system.

METHODS

The last 30 cm of the colon in a screening population were inspected with HD+ alone, in combination with i-Scan (2:1 randomisation) and subsequently with chromoendoscopy. All lesions were characterized and targeted biopsies were performed.

RESULTS

i-Scan augmented in 69 patients the identification of lesions from 176 to 335 (p<0.001) and chromoendoscopy to 646 (p<0.001). The additional lesions were mainly flat (type IIb, 74%), which were only recognized using i-Scan or chromoendoscopy. The amount of neoplasias was not significantly different (HD+: 5, i-Scan: 11, Chromoendoscopy: 11), but all could correctly be predicted using i-Scan or chromoendoscopy.

CONCLUSIONS

HD+ colonoscopy with and without i-Scan unmask a plethora of small lesions but chromoendoscopy can even advance the number. However, i-Scan was able to predict neoplasia as precisely as chromoendoscopy and might shortly replace chromoendoscopy as a more time efficient tool.

High-definition endoscopy with i-Scan and Lugol's solution for more precise detection of mucosal breaks in patients with reflux symptoms

BACKGROUND AND STUDY AIMS

Patients with gastroesophageal reflux disease are subdivided into non-erosive (NERD) and erosive reflux disease (ERD). The newly available EPKi processor enables high-definition resolution above HDTV standard (HD+). The aim of the study was to test the efficacy of HD+ esophagogastroduodenoscopy alone and in conjunction with i-Scan (newly developed postprocessing digital filter) and chromoendoscopy (Lugol's solution) for differentiation of reflux patients.

METHODS

The distal esophagus of patients with heartburn was inspected with three imaging modalities. HD+ was followed by i-Scan and 15-mL Lugol's solution (1.5 %). The esophagus was evaluated for mucosal breaks (Los Angeles Classification [LA]). Small visible changes were also characterized, and targeted biopsies were performed. End points of the study were the presence and grade of esophagitis and the number of circumscribed changes.

RESULTS

A total of 50 patients were included (female 29; mean age 54.7 years). HD+ identified nine patients with mucosal breaks (LA 7A; 2C), i-Scan was able to detect 12 patients (LA 8A; 2B; 2C; 0D) ( P = n. s.) and chromoendoscopy identified 25 patients (LA 16A; 7B; 1C, 1D) ( P < 0.01). Furthermore, a higher grade of esophagitis was recognized by using i-Scan and Lugol's solution in 19 patients. The number of circumscribed lesions could be increased from 21 (HD+) to 58 (i-Scan) ( P < 0.01), and up to 85 after Lugol spraying ( P < 0.01).

CONCLUSIONS

Lugol's solution in conjunction with HD+ endoscopy significantly improves the identification of patients with esophagitis and reduces misclassification. The i-Scan filter and chromoendoscopy help to identify reflux-associated lesions.

Novel imaging modalities in the detection of oesophageal neoplasia

The prognosis of oesophageal neoplasia is dependent on the stage of the disease at the time of detection. Early lesions have an excellent prognosis in contrast to more advanced stages that usually have a dismal prognosis. Therefore, the early detection of these lesions is of the utmost importance. In recent years, several new techniques have been introduced to improve the endoscopic detection of early lesions. The most important improvement, in general, has been the introduction of high-resolution/high-definition endoscopy into daily clinical practice. The value of superimposing techniques such as chromoendoscopy, narrow band imaging and computed virtual chromoendoscopy onto high-resolution/high-definition endoscopy will have to be proven in randomised cross-over trials comparing these techniques with standard techniques. Important future adjuncts to white-light endoscopy serving as 'red-flag' techniques for the detection of early neoplasia may be broad field functional imaging techniques such as video autofluorescence endoscopy. In addition, real-time histopathology during endoscopy has become possible with endocytoscopy and confocal endomicroscopy. The clinical value of these techniques needs to be ascertained in the coming years.

Dynamic in vivo imaging of microvasculature and perfusion by miniaturized confocal laser microscopy

INTRODUCTION

Microvasculature and associated pathologies mandate dynamic imaging. We evaluated a novel miniaturized confocal laser scanning probe for in vivo visualization of blood vessels, blood flow, cell tracking and perfusion in both healthy rodents and disease models.

METHODS

The hand-held confocal microscopy system allowed a 500- to 2,400-fold magnification at a dynamically variable imaging depth. Different intravital stains were used alone or in combination for tissue, nuclear, plasma and vascular endothelial cell staining and for blood flow visualization, and targeted staining for individual cell populations.

RESULTS

Precision optical sectioning yielded high-resolution images in vivo. Leucocyte-endothelium interactions in brain microvasculature were followed in serial sections. A microthrombosis was identified after sequential injection of FITC-labelled erythrocytes, FITC-dextran and acriflavine. Glomerular alterations were visualized in the MRL/lprmouse model of lupus nephritis.

DISCUSSION

Intravital confocal microscopy with a miniaturized hand-held probe combines high-resolution subsurface imaging in real time for dynamic visualization of vessels, cells, blood flow and associated pathologies, permitting a truly comprehensive vascular imaging in vivo at the cellular level.

In vivo confocal laser endomicroscopy of the human liver: a novel method for assessing liver microarchitecture in real time

BACKGROUND AND STUDY AIMS

Confocal endomicroscopy is a unique novel tool for in vivo histology in humans. Due to limitations imposed by the form of the equipment and by sterilization workflows, its use has been limited to the gastrointestinal tract so far. We have developed a rigid miniaturized probe for confocal endomicroscopy of the human liver during laparoscopy.

PATIENTS AND METHODS

To assess the feasibility and potential clinical value of this new system (diameter 6.3 mm), 25 patients with liver disease were examined during routine minilaparoscopy under conscious sedation.

RESULTS

Subsurface serial images (from surface to 250 microm) were generated in real time after fluorescein injection, permitting visualization of hepatocytes, bile ducts, sinusoids, and collagen fibers in vivo. Typical appearances of liver diseases were identified. Confocal diagnosis of moderate-to-severe steatosis and pericellular fibrosis correlated well with histopathologic analysis of subsequent biopsies (83.3 % and 84.6 %, respectively). In addition, intra-abdominal structures such as gallbladder, omentum, and stomach were analyzed by endomicroscopy.

CONCLUSIONS

A miniaturized imaging system for confocal laparoscopy allowed in vivo microscopic analysis of healthy and diseased human liver for the first time during ongoing minilaparoscopy. Although such in vivo imaging does not yet compete with conventional histopathology, this novel confocal laparoscopy system may be of future relevance for immediate morphodynamic analysis in liver disease and the targeting of biopsies in vivo.

Methylene blue-aided cholangioscopy in patients with biliary strictures: feasibility and outcome analysis

BACKGROUND AND STUDY AIMS

Chromoendoscopy using methylene blue is employed in the gastrointestinal tract to delineate neoplastic lesions. We tested the value of chromoendoscopy during choledochoscopy for characterization of local inflammation, neoplasias, and other alterations in patients with biliary strictures.

METHODS

Patients with suspected biliary lesions were scheduled for endoscopic retrograde cholangiography with subsequent cholangioscopy. After initial inspection of the bile duct, 15 ml methylene blue (0.1 %) was administered via the working channel of the cholangioscope. Newly appearing circumscribed or unstained lesions were judged according to their macroscopic type and staining features. Methylene-blue-aided diagnosis was compared with either clinical follow-up of the patients or, in some cases, with the results of targeted biopsies.

RESULTS

A total of 55 patients [biliary stenosis/cholestasis of unknown origin (n = 24), stenosis after orthotopic liver transplantation (n = 11), primary sclerosing cholangitis (n = 20)] were included. Methylene blue unmasked subtle mucosal changes and permitted macroscopic characterization of circumscribed lesions. Characteristic surface staining patterns were seen in chronic inflammation, dysplasia, and ischemic-type biliary lesions. Nondysplastic mucosa appeared homogeneously stained, whereas scarred strictures showed a weak uptake of methylene blue.

CONCLUSION

In this prospective feasibility study, methylene-blue-aided cholangioscopy was used for the first time to define different staining patterns of the bile duct. The differences in staining patterns identified normal, dysplastic, and inflamed mucosa of the bile duct, as was proved by follow-up or, in some cases, histology. Whereas homogeneous staining predicted the presence of normal mucosa, absence of staining of circumscribed lesions, or diffused staining of such lesions, represented neoplastic changes or inflammation.

Confocal chromoscopic endomicroscopy is superior to chromoscopy alone for the detection and characterisation of intraepithelial neoplasia in chronic ulcerative colitis

BACKGROUND

The diagnosis of intraepithelial neoplasia is pivotal for ongoing clinical management decisions in ulcerative colitis. Previous studies have compared the diagnostic yield of endomicroscopy with conventional "white light" endoscopy and hence the overall objective increase of endomicroscopy targeted biopsies as compared to chromoscopy guided alone is not apparent.

AIMS

We performed a prospective randomised controlled study to compare the diagnostic yield of intraepithelial neoplasia and cancer in patients undergoing ulcerative colitis screening using chromoscopy assisted endomicroscopy (group A) versus pan-colonic chromoscopy assisted colonoscopy (group B).

METHODS

Patients were randomised in a 1:1 ratio to undergo screening colonoscopy using either chromoscopic endomicroscopy or chromoscopy alone with targeted biopsies. Circumscribed lesions were characterised using endomicroscopy and chromoscopy with pit pattern analysis. Targeted biopsies in addition to conventional 10 cm quadrantic biopsies were taken. Primary outcome addressed the number of intraepithelial neoplasias detected in each group.

RESULTS

Endomicroscopy targeted biopsies significantly increased the yield of intraepithelial neoplasia as compared to pan-chromoscopy and biopsy alone (p<0.001) and also increased the yield of high-grade dysplastic lesions (p<0.001). Endomicroscopy targeted biopsies increased the diagnostic yield of intraepithelial neoplasia as compared to chromoscopy guided biopsies alone by 2.5-fold.

CONCLUSIONS

This is the first randomised controlled study to show the true clinical benefit of endomicroscopy for the in vivo detection and characterisation of intraepithelial neoplasia in chronic ulcerative colitis surveillance colonoscopy. Endomicroscopy with targeted biopsy may potentially be the "gold standard" for the detection of intraepithelial neoplasia in ulcerative colitis.

Confocal chromoscopic endomicroscopy is superior to chromoscopy alone for the detection and characterisation of intraepithelial neoplasia in chronic ulcerative colitis

BACKGROUND

The diagnosis of intraepithelial neoplasia is pivotal for ongoing clinical management decisions in ulcerative colitis. Previous studies have compared the diagnostic yield of endomicroscopy with conventional "white light" endoscopy and hence the overall objective increase of endomicroscopy targeted biopsies as compared to chromoscopy guided alone is not apparent.

AIMS

We performed a prospective randomised controlled study to compare the diagnostic yield of intraepithelial neoplasia and cancer in patients undergoing ulcerative colitis screening using chromoscopy assisted endomicroscopy (group A) versus pan-colonic chromoscopy assisted colonoscopy (group B).

METHODS

Patients were randomised in a 1:1 ratio to undergo screening colonoscopy using either chromoscopic endomicroscopy or chromoscopy alone with targeted biopsies. Circumscribed lesions were characterised using endomicroscopy and chromoscopy with pit pattern analysis. Targeted biopsies in addition to conventional 10 cm quadrantic biopsies were taken. Primary outcome addressed the number of intraepithelial neoplasias detected in each group.

RESULTS

Endomicroscopy targeted biopsies significantly increased the yield of intraepithelial neoplasia as compared to pan-chromoscopy and biopsy alone (p<0.001) and also increased the yield of high-grade dysplastic lesions (p<0.001). Endomicroscopy targeted biopsies increased the diagnostic yield of intraepithelial neoplasia as compared to chromoscopy guided biopsies alone by 2.5-fold.

CONCLUSIONS

This is the first randomised controlled study to show the true clinical benefit of endomicroscopy for the in vivo detection and characterisation of intraepithelial neoplasia in chronic ulcerative colitis surveillance colonoscopy. Endomicroscopy with targeted biopsy may potentially be the "gold standard" for the detection of intraepithelial neoplasia in ulcerative colitis.

[Endosonography of the gastrointestinal tract]

The clinical value of endosonography (EUS) in the gastrointestinal (GI) tract is currently increasing and supported by new imaging techniques. Conventional EUS combined with contrast application or elastography might further refine the diagnostic yield for GI cancers. The present review discusses current standards of EUS and endosonographically guided therapy and discusses newly available imaging modalities.

[Coincidental squamous cell cancers of the esophagus and head and neck: risk and surveillance]

Patients suffering from head and neck cancer (HNC) have or will develop a second esophageal squamous cell cancer (ESCC) in 5 - 14 %. When a second esophageal neoplasm occurs in a HNC patient, the prognosis is generally determined by the ESCC, and unfortunately it is poor. Prospective clinical studies in Japan, Brazil, Taiwan, France and Germany have shown that screening or surveillance using Lugol chromoesophagoscopy enables early detection of second esophageal neoplasias. Such a surveillance results in a survival benefit for HNC patients. Vice versa, ESCC patients also have a risk of 9.3 - 11.4 % for a head and neck cancer. Periodic otolaryngeal examination and pharyngoscopy is recommended for curatively treated ESCC patients. Patients with a so-called field cancerisation of the airways and upper digestive tract thus require an interdisciplinary management and monitoring.

In-vivo microvascular imaging of early squamous-cell cancer of the esophagus by confocal laser endomicroscopy

We present the case of a 63-year-old man with an early esophageal squamous-cell cancer that was visualized and analyzed by fluorescein-aided confocal laser endomicroscopic imaging. Our findings indicate that endomicroscopy is readily able to provide images of microvessels and to differentiate between normal and abnormal tumor vessels. Endomicroscopy therefore has the potential to characterize microvascular changes in early squamous-cell cancer, suggesting that this technique might have major implications for optimizing treatment strategies in modern endoscopy.

In-vivo confocal real-time mini-microscopy in animal models of human inflammatory and neoplastic diseases

BACKGROUND AND STUDY AIMS

Although various improvements in tissue imaging modalities have recently been achieved, in-vivo molecular and subsurface imaging in the field of gastroenterology remains a technical challenge. In this study we evaluated a newly developed, handheld, miniaturized confocal laser microscopy probe for real-time in-vivo molecular and subsurface imaging in rodent models of human disease.

MATERIALS AND METHODS

The minimicroscope uses a 488-nm, single line laser for fluorophore excitation. The optical slice thickness is 7 microm, the lateral resolution 0.7 microm. The range of the z-axis is 0-250 microm below the tissue surface. Imaging was performed using different fluorescent staining protocols; 5-carboxyfluorescein-labeled octreotate was synthesized for targeted molecular imaging.

RESULTS

Cellular and subcellular details of the gastrointestinal tract could be visualized in vivo at high resolution. Confocal real-time microscopy allowed in-vivo identification of tumor vessels and liver metastases, as well as diagnosis of focal hepatic inflammation, necrosis, and associated perfusion anomalies. Somatostatin-receptor targeting permitted in-vivo molecular staining of AR42-J-induced carcinoma and pancreatic islet cells.

CONCLUSIONS

Confocal mini-microscopy allows rapid in-vivo molecular and subsurface imaging of normal and pathological tissue in the gastrointestinal tract at high resolution. Because this technology is applicable to humans, it might impact on future in-vivo microsocpic and molecular diagnosis of diseases such as cancer and inflammation.

Confocal laser endomicroscopy: technical status and current indications

Confocal laser endomicroscopy is a newly introduced endoscopic tool that makes it possible to carry out confocal microscopic examination of the mucosal layer during ongoing endoscopy. Different types of tissue and diseases can be diagnosed immediately, facilitating early diagnosis of gastrointestinal cancer. Analysis of the in vivo microarchitecture is helpful in targeting biopsies to relevant areas. In addition, 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 (e.g., in vivo receptor analysis).

Confocal laser endomicroscopy: technical status and current indications

Confocal laser endomicroscopy is a newly introduced endoscopic tool that makes it possible to carry out confocal microscopic examination of the mucosal layer during ongoing endoscopy. Different types of tissue and diseases can be diagnosed immediately, facilitating early diagnosis of gastrointestinal cancer. Analysis of the in vivo microarchitecture is helpful in targeting biopsies to relevant areas. In addition, 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 (e.g., in vivo receptor analysis).

[Giant bile duct stones in a patient with a 4-year remaining biliary stent]

We report on a 67-year-old female patient who presented in July 2005 with sudden onset of pain in the right upper abdomen. The patient had undergone cholecystectomy in 1987. Because of recurrent complaints in the right upper abdomen, a pigtail stent was placed into the common hepatic duct in 2001. When the patients presented now, the laboratory tests including liver enzymes were within normal ranges. Endoscopic retrograde cholangiography, however, revealed a remaining 10-French, impacted double pigtail endoprosthesis that was obstructed by sludge as well as multiple giant bile duct stones of 20 to 30 mm in size. The giant stones could be finally removed by the combined use of ESWL and endoscopic techniques. This case demonstrates that impacted stents may favour the development of giant bile duct stones that may result in clinical symptoms only after prolonged periods of time.

[Massive hemorrhage in a 28-year-old male patient with intestinal Behçet's disease]

A 28-year-old man was admitted to the emergency room of our hospital after syncope and acute gastrointestinal bleeding. On the basis of numerous oral and genital ulcerations as well as uveitis anterior and erythema nodosum, the diagnosis of Behçet's disease had been confirmed previously. The bleeding focus could not be detected by endoscopy. During the next days recurrent massive hemorrhages occurred in spite of immunosuppressive therapy with steroids. Angiography revealed a circumscribed bleeding source in the colon transversum near the left colonic flexure, which was treated by superselective coil embolization. A massive hemorrhage reoccurred and required a surgical approach with a Hartmann procedure. Histology depicted bleeding into the submucosa and mucosa and an ulcer in this area as well as lymphatic infiltration of the mucosa. Immunosuppressive therapy was intensified with azathioprine and resulted in a dramatic improvement of the oral and genital ulcers. In addition, no further gastrointestinal hemorrhage occurred. Due to its higher prevalence in patients from eastern Asia, Behçet's disease poses an important differential diagnosis of intestinal hemorrhage in patients of this descent.

Acetic acid-guided biopsies after magnifying endoscopy compared with random biopsies in the detection of Barrett's esophagus: a prospective randomized trial with crossover design

BACKGROUND

In contrast to standard video endoscopy, magnifying endoscopy after local acetic acid application enables recognition of mucosal surface architecture.

OBJECTIVE

To investigate the diagnostic yield of magnifying endoscopy with acetic acid-targeted biopsies compared to random, 4-quadrant biopsies.

DESIGN

Prospective randomized trial (ratio 1:1) with crossover design.

SETTING

Two referral hospitals in Germany.

PATIENTS

Thirty-one patients with Barrett's esophagus or visible columnar-lined lower esophagus.

INTERVENTIONS

Patients were randomized to undergo either standard video endoscopy with 4-quadrant biopsies or magnifying endoscopy in conjunction with acetic acid application. All patients were re-examined 14 days after the initial endoscopy with the corresponding procedure.

MAIN OUTCOME MEASUREMENTS

Primary outcome analysis (per protocol and per biopsy) was the histological proof of Barrett's epithelium. Secondary outcome analysis was the correlation between the surface architecture and the presence of Barrett's epithelium and the needed number of biopsies to confirm Barrett's epithelium for the 2 different procedures.

RESULTS

Magnifying endoscopy enabled the prediction of Barrett's epithelium with a sensitivity of 100% and a specificity of 66%, respectively (accuracy 83.8%). Acetic acid-guided biopsies obtained a significantly higher percentage of tissues containing SCE (78%; 188/241) compared to random biopsies (57%; 159/280).

LIMITATIONS

No data on the diagnosis of Barrett's dysplasia.

CONCLUSION

Magnifying endoscopy with acetic acid-guided biopsies is superior to standard video endoscopy with random biopsies, and the number of biopsies needed to confirm Barrett's epithelium is half as much when compared to random biopsies.

Magnifying chromoendoscopy for the detection of premalignant gastrointestinal lesions

The prognosis for patients with malignancies of the gastrointestinal tract is strictly dependent on the early detection of premalignant and malignant lesions. At present, endoscopy can be performed with new, powerful high-resolution or magnifying endoscopes. Comparable to the rapid development in chip technology, the optic features of the newly designed endoscopes offer resolutions that allow new mucosal surface details to be seen. In conjunction with chromoendoscopy, the newly discovered tool of video endoscopy is much easier to use and more impressive than previously used fibreoptic endoscopy. This review summarises the value of magnifying endoscopy in the upper and lower gastrointestinal tract and focuses on gastroesophageal reflux disease and early gastric and colorectal cancer.

Endomikroskopie

Endomicroscopy becomes possible due to the integration of a miniaturized confocal microscope in the distal tip of a conventional endoscope. Endomicroscopy enables subsurface analysis of the gut mucosa and in vivo histology during ongoing endoscopy in full resolution by point scanning laser fluorescence analysis. Cellular, vascular and connective structures can be seen in detail. Graduation of cellular changes with endomicroscopy allows an immediate in-vivo diagnosis of different gastrointestinal diseases. The diagnostic spectrum of confocal endomicroscopy is currently expanding from screening and surveillance for colorectal cancer towards Barrett's esophagus, Helicobacter pylori associated gastritis and early gastric cancer. The new detailed images seen with confocal laser endomicroscopy are unequivocally the beginning of a new era where this optical development will allow a unique look on cellular structures and functions at and below the surface of the gut.

Colonoscopy, tumors, and inflammatory bowel disease - new diagnostic methods

Accurate detection of premalignant lesions and early cancers in the colon is essential for curative endoscopic or surgical therapy, since the prognosis for the affected patients is closely related to the size and stage of the neoplastic lesion. Total colonoscopy is the accepted gold standard for screening and surveillance of colorectal cancer. This review summarizes recently published diagnostic developments and key findings in the areas of colonoscopy, colonic tumors, and inflammatory bowel diseases. Relevant findings have been reported for chromo-endoscopy in the diagnosis of colitis-associated neoplasia, as well as flat and depressed adenomas. Real-time Doppler capabilities have now been added to endoscopic optical coherence tomography; the results of large-scale testing of narrow-band imaging endoscopy in the colon are being awaited; and fluorescence imaging has recently been added to the facilities available in video endoscopy. Most importantly, endomicroscopy now for the first time allows single-cell subsurface imaging during ongoing colonoscopy procedures, opening the way to in-vivo molecular and functional imaging.