New classification for probe-based confocal laser endomicroscopy in the colon

The Role of Probe-Based Confocal Laser Endomicroscopy (pCLE) in the Diagnosis of Sustained Clinical Complete Response Under Watch-and-Wait Strategy After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Adenocarcinoma: a Score Validation

BACKGROUND

Watch-and-wait strategy has been increasingly accepted for patients with clinical complete response (cCR) after multimodal treatment for locally advanced rectal adenocarcinoma. Close follow-up is essential to the early detection of local regrowth. It was previously demonstrated that probe-based confocal laser endomicroscopy (pCLE) scoring using the combination of epithelial and vascular features might improve the diagnostic accuracy of cCR.

AIM

To validate the pCLE scoring system in the assessment of patients with cCR after neoadjuvant chemoradiotherapy (nCRxt) for advanced rectal adenocarcinoma.

METHODS

Digital rectal examination, pelvic magnetic resonance imaging (MRI), and pCLE were performed in 43 patients with cCR, who presented either a scar (N = 33; 76.7%) or a small ulcer with no signs of tumor, and/or biopsy negative for malignancy (N = 10; 23.3%).

RESULTS

Twenty-five (58.1%) patients were men, and the mean age was 58.4 years. During the follow-up, 12/43 (27.9%) patients presented local regrowth and underwent salvage surgery. There was an association between pCLE diagnostic scoring and final histological report (for patients who underwent surgical resection) or final diagnosis at the latest follow-up (p = 0.0001), while this association was not observed with MRI (p = 0.49). pCLE sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 66.7%, 93.5%, 80%, 88.9%, and 86%, respectively. MRI sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 66.7%, 48.4%, 66.7%, 78.9%, and 53.5%, respectively.

CONCLUSIONS

pCLE scoring system based on epithelial and vascular features improved the diagnosis of sustained cCR and might be recommended during follow-up. pCLE might add some valuable contribution for identifying local regrowth. Trial Registration This protocol was registered at the Clinical Trials (ClinicalTrials.gov identifier NCT02284802).

Real-time in vivo distal margin selection using confocal laser endomicroscopy in transanal total mesorectal excision for rectal cancer

BACKGROUND

Transanal total mesorectal excision (TaTME) allows patients with ultralow rectal cancer to be treated with sphincter-saving surgery. However, accurate delineation of the distal resection margin (DRM), which is essential to achieve R0 resection for low rectal cancer in TaTME, is technically demanding.

AIM

To assess the feasibility of optical biopsy using probe-based confocal laser endomicroscopy (pCLE) to select the DRM during TaTME for low rectal cancer.

METHODS

A total of 43 consecutive patients who were diagnosed with low rectal cancer and scheduled for TaTME were prospectively enrolled from January 2019 to January 2021. pCLE was used to determine the distal edge of the tumor as well as the DRM during surgery. The final pathological report was used as the gold standard. The diagnostic accuracy of pCLE examination was calculated.

RESULTS

A total of 86 pCLE videos of 43 patients were included in the analyses. The sensitivity, specificity and accuracy of real-time pCLE examination were 90.00% [95% confidence interval (CI): 76.34%-97.21%], 86.96% (95%CI: 73.74%-95.06%) and 88.37% (95%CI: 79.65%-94.28%), respectively. The accuracy of blinded pCLE reinterpretation was 86.05% (95%CI: 76.89%-92.58%). Furthermore, our results show satisfactory interobserver agreement (κ = 0.767, standard error = 0.069) for the detection of cancer tissue by pCLE. There were no positive DRMs (≤ 1 mm) in this study. The median DRM was 7 mm [interquartile range (IQR) = 5-10 mm]. The median Wexner score was 5 (IQR = 3-6) at 6 mo after stoma closure.

CONCLUSION

Real-time in vivo pCLE examination is feasible and safe for selecting the DRM during TaTME for low rectal cancer (clinical trial registration number: NCT04016948).

Assessments of microvascular function in organ systems

Microvascular disease plays critical roles in the dysfunction of all organ systems, and there are many methods available to assess the microvasculature. These methods can either assess the target organ directly or assess an easily accessible organ such as the skin or retina so that inferences can be extrapolated to the other systems and/or related diseases. Despite the abundance of exploratory research on some of these modalities and their possible applications, there is a general lack of clinical use. This deficiency is likely due to two main reasons: the need for standardization of protocols to establish a role in clinical practice or the lack of therapies targeted toward microvascular dysfunction. Also, there remain some questions to be answered about the coronary microvasculature, as it is complex, heterogeneous, and difficult to visualize in vivo even with advanced imaging technology. This review will discuss novel approaches that are being used to assess microvasculature health in several key organ systems, and evaluate their clinical utility and scope for further development.

Diagnosis of Clinical Complete Response by Probe-Based Confocal Laser Endomicroscopy (pCLE) After Chemoradiation for Advanced Rectal Cancer

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRxt) followed by radical surgery is the optimal treatment for advanced rectal adenocarcinoma. Patients with clinical complete response (cCR) may be followed closely without immediate surgery. Probe-based confocal laser endomicroscopy (pCLE) is a real-time in vivo method that allows acquisition of optical biopsies with 1000 times magnification, evaluating both epithelial and vascular patterns.

AIM

To evaluate the role of pCLE in the diagnosis of cCR after nCRxt for advanced rectal adenocarcinoma.

METHODS

pCLE was performed in 47 patients with locally advanced rectal adenocarcinoma (T3/T4, or N+) who underwent nCRxt (5-fluorouracil, 5040 cGy).

RESULTS

Twenty-seven (57.5%) patients were men, and the mean age was 62.8 years. Thirty-seven had partial response confirmed by pCLE. Ten (21.3%) patients had good endoscopic response and presented small ulcer (n = 5) or residual scar (n = 5). After nCRxt, the essential features to differentiate malignancy from post-radiation alterations at pCLE were the presence of irregular crypts, budding, back-to-back glands, cribriform pattern, increased vessel/crypt ratio, and fluorescein leakage. A scoring system was created considering these epithelial and vascular features, with high accuracy for differentiating patients with complete response from those with residual neoplasia (p < 0.00001). pCLE sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 100%, 71.4%, 95.2%, 100%, and 95.7%, respectively.

CONCLUSIONS

(1) pCLE evaluation of epithelial and vascular features may improve the diagnosis of cCR and may alter patient management; (2) pCLE might be valuable for identifying patients with advanced rectal cancer who will benefit from watch and wait strategy, avoiding immediate surgical treatment.

Artificial intelligence in gastrointestinal endoscopy

Background and Aims

Artificial intelligence (AI)-based applications have transformed several industries and are widely used in various consumer products and services. In medicine, AI is primarily being used for image classification and natural language processing and has great potential to affect image-based specialties such as radiology, pathology, and gastroenterology (GE). This document reviews the reported applications of AI in GE, focusing on endoscopic image analysis.

Methods

The MEDLINE database was searched through May 2020 for relevant articles by using key words such as machine learning, deep learning, artificial intelligence, computer-aided diagnosis, convolutional neural networks, GI endoscopy, and endoscopic image analysis. References and citations of the retrieved articles were also evaluated to identify pertinent studies. The manuscript was drafted by 2 authors and reviewed in person by members of the American Society for Gastrointestinal Endoscopy Technology Committee and subsequently by the American Society for Gastrointestinal Endoscopy Governing Board.

Results

Deep learning techniques such as convolutional neural networks have been used in several areas of GI endoscopy, including colorectal polyp detection and classification, analysis of endoscopic images for diagnosis of Helicobacter pylori infection, detection and depth assessment of early gastric cancer, dysplasia in Barrett’s esophagus, and detection of various abnormalities in wireless capsule endoscopy images.

Conclusions

The implementation of AI technologies across multiple GI endoscopic applications has the potential to transform clinical practice favorably and improve the efficiency and accuracy of current diagnostic methods.

Rapid, High-Resolution, Label-Free, and 3-Dimensional Imaging to Differentiate Colorectal Adenomas and Non-Neoplastic Polyps With Micro-Optical Coherence Tomography

“Resect and discard” paradigm is one of the main strategies to deal with colorectal diminutive polyps after optical diagnosis. However, there are risks that unrecognized potentially malignant lesions are discarded without accurate diagnosis. The purpose of this study is to validate the potential of micro-optical coherence tomography (μOCT) to improve the diagnostic accuracy of colorectal lesions and help endoscopists make better clinical decision without additional pathology costs.

Intravital Imaging Techniques for Biomedical and Clinical Research

Intravital imaging, the direct visualization of cells and tissues within a living animal, is a technique that has been employed for the better part of a century. The advent of confocal and multiphoton microscopy has dramatically improved the power of intravital imaging, making it possible to obtain optical sections of tissues non-destructively. This review discusses the various techniques used for intravital imaging, describes how intravital imaging provides information about cellular and tissue dynamics not possible to be garnered by other techniques, and details several ways in which intravital imaging is making a direct impact on the clinical care of patients. © 2019 International Society for Advancement of Cytometry.

Shedding light on fibered confocal fluorescence microscopy: Applications in biomedical imaging and therapies

Discoveries of major importance in life sciences and preclinical research are linked to the invention of microscopes that enable imaging of cells and their microstructures. Imaging technologies involving in vivo procedures using fluorescent dyes that permit labelling of cells have been developed over the last two decades. Fibered confocal fluorescence microscopy (FCFM) is an imaging technology equipped with fiber-optic probes to deliver light to organs and tissues of live animals. This enables not only in vivo detection of fluorescent signals and visualization of cells, but also the study of dynamic processes, such cell proliferation, apoptosis and angiogenesis, under physiological and pathological conditions. This will allow the diagnosis of diseased organs and tissues and the evaluation of the efficacy of new therapies in animal models of human diseases. The aim of this report is to shed light on FCFM and its potential medical applications and discusses some factors that compromise the reliability and reproducibility of monitoring biological processes by FCFM. This report also highlights the issues concerning animal experimentation and welfare, and the contributions of FCFM to the 3Rs principals, replacement, reduction and refinement.

Ab Externo Imaging of Human Episcleral Vessels Using Fiberoptic Confocal Laser Endomicroscopy

Purpose

There is a growing interest in targeting minimally invasive surgery devices to the aqueous outflow system to optimize treatment outcomes. However, methods to visualize functioning, large-caliber aqueous and episcleral veins in-vivo are lacking. This pilot study establishes an ex-vivo system to evaluate the use of a confocal laser microendoscope to noninvasively image episcleral vessels and quantify regional flow variation along the limbal circumference.

Methods

A fiber-optic confocal laser endomicroscopy (CLE) system with lateral and axial resolution of 3.5 μm and 15 μm, respectively, was used on three porcine and four human eyes. Diluted fluorescein (0.04%) was injected into eyes kept under constant infusion. The microprobe was applied to the sclera 1 mm behind the limbus to acquire real-time video. Image acquisition was performed at 15-degree intervals along the limbal circumference to quantify regional flow variation in human eyes.

Results

Vascular structures were visualized in whole human eyes without processing. Schlemm's canal was visualized only after a scleral flap was created. Fluorescent signal intensity and vessel diameter variation were observed along the limbal circumference, with the inferior quadrant having a statistically higher fluorescein signal compared to the other quadrants in human eyes (P < 0.05).

Conclusion

This study demonstrates for the first time that the fiber-optic CLE platform can visualize the episcleral vasculature with high resolution ex-vivo with minimal tissue manipulation. Intravascular signal intensities and vessel diameters were acquired in real-time; such information can help select target areas for minimally invasive glaucoma surgery (MIGS) to achieve greater intraocular pressure reduction.

Artificial intelligence and colonoscopy: Current status and future perspectives

BACKGROUND AND AIM

Application of artificial intelligence in medicine is now attracting substantial attention. In the field of gastrointestinal endoscopy, computer-aided diagnosis (CAD) for colonoscopy is the most investigated area, although it is still in the preclinical phase. Because colonoscopy is carried out by humans, it is inherently an imperfect procedure. CAD assistance is expected to improve its quality regarding automated polyp detection and characterization (i.e. predicting the polyp's pathology). It could help prevent endoscopists from missing polyps as well as provide a precise optical diagnosis for those detected. Ultimately, these functions that CAD provides could produce a higher adenoma detection rate and reduce the cost of polypectomy for hyperplastic polyps.

METHODS AND RESULTS

Currently, research on automated polyp detection has been limited to experimental assessments using an algorithm based on ex vivo videos or static images. Performance for clinical use was reported to have >90% sensitivity with acceptable specificity. In contrast, research on automated polyp characterization seems to surpass that for polyp detection. Prospective studies of in vivo use of artificial intelligence technologies have been reported by several groups, some of which showed a >90% negative predictive value for differentiating diminutive (≤5 mm) rectosigmoid adenomas, which exceeded the threshold for optical biopsy.

CONCLUSION

We introduce the potential of using CAD for colonoscopy and describe the most recent conditions for regulatory approval for artificial intelligence-assisted medical devices.

Quantitative analysis of in vivo high-resolution microendoscopic images for the detection of neoplastic colorectal polyps

Colonoscopy is routinely performed for colorectal cancer screening but lacks the capability to accurately characterize precursor lesions and early cancers. High-resolution microendoscopy (HRME) is a low-cost imaging tool to visualize colorectal polyps with subcellular resolution. We present a computer-aided algorithm to evaluate HRME images of colorectal polyps and classify neoplastic from benign lesions. Using histopathology as the gold standard, clinically relevant features based on luminal morphology and texture are quantified to build the classification algorithm. We demonstrate that adenomatous polyps can be identified with a sensitivity and specificity of 100% and 80% using a two-feature linear discriminant model in a pilot test set. The classification algorithm presented here offers an objective framework to detect adenomatous lesions in the colon with high accuracy and can potentially improve real-time assessment of colorectal polyps.

Enhanced Visualization: From Intraoperative Tissue Differentiation to Augmented Reality

Background

Optimal visualization of the operative field and methods that additionally provide supportive optical information form the basis for target-directed and successful surgery. This article strives to give an overview of current enhanced visualization techniques in visceral surgery and to highlight future developments.

Methods

The article was written as a comprehensive review on this topic and is based on a MEDLINE search and ongoing research from our own group and from other working groups.

Results

Various techniques for enhanced visualization are described comprising augmented reality, unspecific and targeted staining methods, and optical modalities such as narrow-band imaging. All facilitate our surgical performance; however, due to missing randomized controlled studies for most of the innovations reported on, the available evidence is low.

Conclusion

Many new visualization technologies are emerging with the aim to improve our perception of the surgical field leading to less invasive, target-oriented, and elegant treatment forms that are of significant benefit to our patients.

Feasibility of real-time intestinal bloodstream evaluation using probe-based confocal laser endomicroscopy in a porcine intestinal ischemia model

BACKGROUND

Intestinal ischemia can lead to fatal complications if left unrecognized during surgery. The current techniques of intraoperative microvascular assessment remain subjective. Probe-based confocal laser endomicroscopy (pCLE) has the potential to objectively evaluate microvascular blood flow in real-time setting. The present study evaluated the technical feasibility of real-time intestinal bloodstream evaluation using pCLE in a porcine intestinal ischemia model.

METHODS

Seven pigs were used. The intestinal ischemia model was prepared by sequentially dividing the mesenteric blood vessels. The intestinal bloodstream was evaluated on its serosal surface using pCLE (Cellvizio 488 probe, Ultra Mini O) at every 1-cm segment from a vessel-preservation border (i.e., the cut end of the vessel). Images of the blood vessels and flow of red blood cells (RBCs) in each visualized vessel were semi-qualitatively assessed using a 3-scale scoring system. In addition, 25 surgeons blindly assessed the 10 movies recorded at 0, 1, 2, 3, and 5 cm from a vessel-preservation border using a 4-scale scoring system to confirm the consistency of the evaluation of the pCLE system.

RESULTS

Images of the blood vessels were successfully obtained from the cut end of the vessel to the segment 4 cm away. Good unidirectional flow of RBCs was observed from the cut end to the 2-cm segment, whereas the flow became bidirectional between 2 and 3 cm segments. Beyond 4 cm, no flow images were obtained. The specimen obtained from the segment beyond 4 cm showed remarkable mucosal color change, which was confirmed as a necrotic change histologically. The evaluations from the cut end of the vessel to the segment 1 cm away by surgeons were excellent or good and it was almost consistent.

CONCLUSIONS

Real-time bloodstream evaluation using pCLE is feasible and potentially effective for predicting intestinal ischemia during surgery.

Probe-based confocal laser endomicroscopy for in vivo evaluation of the tumor vasculature in gastric and rectal carcinomas

Probe-based Confocal Laser Endomicroscopy (pCLE) is a powerful imaging technique that allows to perform gastrointestinal endomicroscopy at subcellular resolution. The aim of this study was to assess the use of pCLE to evaluate tumor angiogenesis in rectal and gastric cancers. A total of 35 consecutive patients with gastric and 91 with rectal carcinomas underwent endoscopy and pCLE during the same examination. Vascular assessment was based on vessel shape and size, vessel permeability and blood flow, and allowed the creation of an angiogenic score ranging from 0, for normal vasculature, to 4, for aberrant vasculature. A significant difference for the presence of vessels with large diameter and defective blood flow was found between rectal and gastric cancers. Overall, rectal cancers displayed a higher angiogenic score compared to gastric cancers. Conventional therapy induced a striking reduction in the angiogenic score only in rectal cancer patients. Taken together, our findings suggest that the pCLE technology is suitable for the evaluation of the tumor microvasculature abnormalities. Therefore, the real-time assessment of the vasculature status may represent a promising approach to predict the efficacy of the treatments and improve the clinical management of patients with gastric or rectal carcinomas.

Patient optimization for surgery relating to Crohn's disease

The majority of patients with Crohn's disease require abdominal surgery during their lifetime, some of whom will require multiple operations. Postoperative complications are seen more frequently in patients requiring abdominal surgery for Crohn's disease than in patients requiring abdominal surgery for other conditions. In this article, we review the evidence supporting preoperative optimization, discussing strategies that potentially improve surgical outcomes and reduce perioperative morbidity and mortality. We discuss the roles of adequate cross-sectional imaging, nutritional optimization, appropriate adjustments of medical therapy, management of preoperative abscesses and phlegmons, smoking cessation and thromboembolic prophylaxis. We also review operation-related factors, and discuss their potential implications with respect to postoperative complications. Overall, the literature suggests that preoperative management has a major effect on postoperative outcomes.

Diagnostic yield of endomicroscopy for dysplasia in primary sclerosing cholangitis associated inflammatory bowel disease: a feasibility study

BACKGROUND AND STUDY AIMS

Primary sclerosing cholangitis associated inflammatory bowel disease (PSC-IBD) is characterized by a high risk of colorectal dysplasia. Surveillance colonoscopies with random biopsies have doubtful power for dysplasia detection. Our aim was to prospectively investigate the feasibility and efficacy of pCLE in surveillance colonoscopies in patients with PSC-IBD.

PATIENTS AND METHODS

Sixty-nine patients with PSC-IBD underwent colonoscopy in 2 steps. On the way from rectum to cecum, the mucosa was inspected with high definition endoscopy (HDE) and random biopsies were taken according to the standard routine. On the way from cecum to rectum, fluorescein-enhanced pCLE and chromoendoscopy were performed. Regions where random biopsies had been taken, as well as visible lesions, were examined with pCLE and targeted biopsies were taken of lesions suspicious for dysplasia. Two investigators, blinded to histology and endoscopy results, analyzed all pCLE videos off-line.

RESULTS

Nineteen biopsies obtained in 13 patients (17 targeted biopsies, 2 random biopsies) revealed the presence of low-grade dysplasia. Thirteen lesions with dysplasia were endoscopically visible but by using pCLE-targeted biopsies, additional endoscopically invisible dysplasias in 4 biopsies obtained from 3 patients were detected. The sensitivity, specificity, and accuracy of pCLE in predicting dysplasia were respectively 89 % (95 % CI: 65 - 98), 96 % (95 % CI: 94 - 97), and 96 % (95 % CI: 94 - 97). pCLE showed a good performance for differentiating neoplastic from non-neoplastic mucosa with negative predictive value of 99 %.

CONCLUSIONS

pCLE in PSC-IBD surveillance is feasible and may be a good complement to HDE. Future research should aim at elucidating whether real-time pCLE is applicable in PSC-IBD surveillance.

Human colorectal mucosal microbiota correlates with its host niche physiology revealed by endomicroscopy

The human gut microbiota plays a pivotal role in the maintenance of health, but how the microbiota interacts with the host at the colorectal mucosa is poorly understood. We proposed that confocal laser endomicroscopy (CLE) might help to untangle this relationship by providing in vivo physiological information of the mucosa. We used CLE to evaluate the in vivo physiology of human colorectal mucosa, and the mucosal microbiota was quantified using 16 s rDNA pyrosequencing. The human mucosal microbiota agglomerated to three major clusters dominated by Prevotella, Bacteroides and Lactococcus. The mucosal microbiota clusters did not significantly correlate with the disease status or biopsy sites but closely correlated with the mucosal niche physiology, which was non-invasively revealed by CLE. Inflammation tilted two subnetworks within the mucosal microbiota. Infiltration of inflammatory cells significantly correlated with multiple components in the predicted metagenome, such as the VirD2 component of the type IV secretory pathway. Our data suggest that a close correlation exists between the mucosal microbiota and the colorectal mucosal physiology, and CLE is a clinically available tool that can be used to facilitate the study of the in vivo correlation between colorectal mucosal physiology and the mucosal microbiota.

Use of probe-based confocal laser endomicroscopy (pCLE) in gastrointestinal applications. A consensus report based on clinical evidence

BACKGROUND

Probe-based confocal laser endomicroscopy (pCLE) provides microscopic imaging during an endoscopic procedure. Its introduction as a standard modality in gastroenterology has brought significant progress in management strategies, affecting many aspects of clinical care and requiring standardisation of practice and training.

OBJECTIVE

This study aimed to provide guidance on the standardisation of its practice and training in Barrett's oesophagus, biliary strictures, colorectal lesions and inflammatory bowel diseases.

METHODS

Initial statements were developed by five group leaders, based on the available clinical evidence. These statements were then voted and edited by the 26 participants, using a modified Delphi approach. After two rounds of votes, statements were validated if the threshold of agreement was higher than 75%.

RESULTS

Twenty-six experts participated and, among a total of 77 statements, 61 were adopted (79%) and 16 were rejected (21%). The adoption of each statement was justified by the grade of evidence.

CONCLUSION

pCLE should be used to enhance the diagnostic arsenal in the evaluation of these indications, by providing microscopic information which improves the diagnostic performance of the physician. In order actually to implement this technology in the clinical routine, and to ensure good practice, standardised initial and continuing institutional training programmes should be established.

Laparoscopic manipulation of a probe-based confocal laser endomicroscope using a steerable intravascular catheter

Probe-based confocal laser endomicroscopy is an emerging imaging modality that enables visualization of histologic details during endoscopy and surgery. A method of guiding the probe with millimeter accuracy is required to enable imaging in all regions of the abdomen accessed during laparoscopy. On the basis of a porcine model of laparoscopic liver resection, we report our experience of using a steerable intravascular catheter to guide a probe-based confocal laser endomicroscope.

Probe-based confocal laser endomicroscopy and fluorescence-based enhanced reality for real-time assessment of intestinal microcirculation in a porcine model of sigmoid ischemia

BACKGROUND AND AIM

Surgeons currently rely on visual clues to estimate the presence of sufficient vascularity for safe anastomosis. We aimed to assess the accuracy of endoluminal confocal laser endomicroscopy (CLE) and laparoscopic fluorescence-based enhanced reality (FLER), using near-infrared imaging and fluorescence from injected Indocyanine Green, to identify the transition from ischemic to vascular areas in a porcine model of mesenteric ischemia.

METHODS

Six pigs underwent 1-h sigmoid segmental ischemia. The ischemic area was evaluated by clinical assessment and FLER to determine presumed viable margins. For each sigmoid colon, 5 regions of interest (ROIs) were identified: ischemic (ROI 1), presumed viable margins ROI 2a (distal) and 2b (proximal), and vascular areas 3a (distal) and 3b (proximal). After injection of fluorescein, CLE scanning of the mucosa from the ischemic area toward viable margins was performed. Capillary blood samples were obtained by puncturing the serosa at the ROIs, and capillary lactates were measured with the EDGE(®) analyzer.

RESULTS

Capillary lactates were significantly higher at ROI 1 (4.91 mmol/L) when compared to resection margins (2.8 mmol/L; mean difference: 2.11; p < 0.05) identified by FLER. There was no significant difference in lactates between ROI1 and resection margins identified by clinical evaluation. In 50 % of cases, ROI 2aCLINIC-2bCLINIC were considered to match (<1 cm distance) with ROI 2aFLER-2bFLER. Confocal analysis revealed specific clues to identify the transition from ischemic to viable areas corresponding to those assessed by FLER in 11/12 cases versus 7/12 for those identified by clinical evaluation.

CONCLUSIONS

In this experimental model, FLER and CLE were more accurate than clinical evaluation to delineate bowel vascularization.

Microscopic imaging in endoscopy: endomicroscopy and endocytoscopy

Performing real-time microscopy has been a vision of endoscopists since the very early phases of gastrointestinal endoscopy. Confocal endomicroscopy, an adaption of confocal laser scanning microscopy, and endocytoscopy, an adaption of white-light microscopy, have been introduced into the endoscopic armamentarium in the past decade. Both techniques yield on-site histological information. Multiple trials have demonstrated the ability of gastroenterologists to obtain and interpret microscopic images from the upper and lower gastrointestinal tract, and also the hepatobiliary-pancreatic system, during endoscopy. Such microscopic information has been successfully used in expert hands to minimize sampling error by 'smart', microscopically targeted biopsies and to guide endoscopic interventions. However, endomicroscopy is also unique in its ability to dynamically visualize cellular processes in their native environment free of artefacts. This ability enables fundamental insights into mechanisms of human diseases in clinical and translational science.

Real-time histology in colonoscopy

Gastrointestinal endoscopy had major technological improvements and novel technologies in recent years. High-definition endoscopy has permitted an increasingly detailed view of the mucosa during colonoscopy. Filter techniques that enhance analysis of vessel and surface structures. Autofluorescence imaging relies on functional imaging of tissue alterations. Endocytoscopy is an ultrahigh-contact microscopy procedure for cellular analysis of the epithelium. Endomicroscopy is an adaption of laser scanning microscopy for real-time intravital surface and subsurface microscopy during endoscopy. With these technologies, endoscopy has moved from prediction of histology based on morphologic patterns toward visualization of cellular and subcellular details, providing real-time histology.

Confocal laser endomicroscopy in neurosurgery: a new technique with much potential

Technical innovations in brain tumour diagnostic and therapy have led to significant improvements of patient outcome and recurrence free interval. The use of technical devices such as surgical microscopes as well as neuronavigational systems have helped localising tumours as much as fluorescent agents, such as 5-aminolaevulinic acid, have helped visualizing pathologically altered tissue. Nonetheless, intraoperative instantaneous frozen sections and histological diagnosis remain the only method of gaining certainty of the nature of the resected tissue. This technique is time consuming and does not provide close-to-real-time information. In gastroenterology, confocal endoscopy closed the gap between tissue resection and histological examination, providing an almost real-time histological diagnosis. The potential of this technique using a confocal laser endoscope EndoMAG1 by Karl Storz Company was evaluated by our group on pig brains, tumour tissue cell cultures, and fresh human tumour specimen. Here, the authors report for the first time on the results of applying this new technique and provide first confocal endoscopic images of various brain and tumour structures. In all, the technique harbours a very promising potential to provide almost real-time intraoperative diagnosis, but further studies are needed to provide evidence for the technique's potential.

Advanced endoscopic imaging for dysplasia surveillance in ulcerative colitis

Ulcerative colitis is a well-characterized chronic inflammatory bowel disease with a significantly increased risk for developing colorectal neoplasia. A rigorous colonoscopy surveillance program has been shown to undoubtedly reduce this risk. White light endoscopy with random 4-quadrant biopsies in addition to target biopsies of suspicious lesions has been considered the standard of care. However, interval cancers between successive surveillance colonoscopies have been identified. Recently, multiple new endoscopic imaging technologies such as standard chromoendoscopy with methylene blue, virtual chromoendoscopy, autofluorescence imaging, confocal laser endomicroscopy and endocytoscopy were developed to provide a more detailed visualization of the mucosa by enhancing morphology and vascularization. This review will provide a comprehensive approach to advanced endoscopic imaging useful for dysplasia surveillance in longstanding ulcerative colitis patients.

Confocal Laser Endomicroscopy: Applications in Clinical and Translational Science—A Comprehensive Review

Confocal laser endomicroscopy (CLE) is a novel tool in the endoscopist’s armamentarium. It allows on-site histological information. The ability of gastroenterologists to interpret such microscopic information has been demonstrated in multiple studies from the upper and lower gastrointestinal tract. Recently, the field of application has expanded to provide hepatobiliary and intra-abdominal CLE imaging. CLE allows “smart,” targeted biopsies and is able to guide endoscopic interventions. But CLE is also translational in its approach and permits functional imaging that significantly impacts on our understanding of gastrointestinal diseases. Molecular imaging with CLE allows detection and characterization of lesions and may even be used for prediction of response to targeted therapy. This paper provides a comprehensive review over current applications of CLE in clinical applications and translational science.

Chromoendoscopy in inflammatory bowel disease

Chromoendoscopy with methylene blue or indigo carmine significantly increases the diagnostic yield of finding intraepithelial neoplasia in patients with longstanding colitis. The number needed to treat is 14 for panchromoendoscopy to identify 1 additional patient with dysplasia. Chromoendoscopy can greatly facilitate the identification of flat lesions harboring intraepithelial neoplasia. Chromoendoscopy can guide biopsies and clearly reduces the amount of biopsies that are needed per patient. Magnifying endoscopy or CLE are additional techniques, which can be used in conjunction with chromoendoscopy to further reduce the amount of biopsies and to further increase the diagnostic yield. Chromoendoscopy is an established clinical procedure and recommended by many gastroenterological societies for surveillance of patients with longstanding ulcerative colitis. Thus, intravital staining should be an essential part of the diagnostic armamentarium of every colonoscopist.

Probe-based confocal laser endomicroscopy evaluation of colon preneoplastic lesions, with particular attention to the aberrant crypt foci, and comparative assessment with histological features obtained by conventional endoscopy

The colorectal carcinoma represents one of the most common and aggressive malignancies, still characterized by an unacceptable mortality rate, mainly due to the high metastatic potential and to a late diagnosis. In the last years, the research community focused on the chance of improving the endoscopic screening to detect neoplastic lesions in a very early stage. Several studies proposed aberrant colonic crypt foci as the earliest recognizable step of transformation in colonic multiphase carcinogenesis. We previously demonstrated the clinical applicability and predictive power of probe-based confocal laser endoscopy (pCLE) in superficial colorectal neoplastic lesions and also characterized in vivo a case of dysplasia-associated lesional mass (DALM) in ulcerative colitis. Now, we aim to evaluate the accuracy of pCLE in the detection of ACF comparing in double-blind manner the microendoscopic and histopathological features resulting from colonic biopsy. By pCLE, we identified specific crypt architecture modifications associated with changes in cellular infiltration and vessels architecture, highlighting a good correspondence between pCLE features and histology.