Feasibility of confocal laser endomicroscopy as an optical biopsy method for SCC on the auricle : an exploratory study.

Optical biopsy of penile cancer with in vivo confocal laser endomicroscopy

Confocal Laser Endomicroscopy of Bladder Tumors Associated With Photodynamic Diagnosis: An Ex Vivo Pilot Study

Intraoperative Optical Biopsy during Robotic Assisted Radical Prostatectomy Using Confocal Endomicroscopy

BackgroundMalignant solitary pulmonary nodules (SPN) have become more prevalent, with upper lobes predilection. Probe-based confocal laser endomicroscopy (pCLE) provides in-vivo imaging of SPN. However, the stiffness of the 1mm confocal probe (AlveoFlex) causes difficult accessibility to the upper lobes. A thinner 600μm probe designed for bile duct exploration (CholangioFlex) has the potential to reach the upper lobes.ObjectivesTo examine the accessibility of malignant SPNs in all segments of the lungs using either the 0.6mm or 1.4 mm probe and to assess the quality and inter observer interpretation of SPN confocal imaging obtained from either miniprobes.MethodsRadial(r)-EBUS was used to locate and sample the SPN. In-vivo pCLE analysis of the SPN was performed using either CholangioFlex (apical and posterior segments of the upper lobes) or AlveoFlex (other segments) introduced into the guide sheath before sampling. pCLE features were compared between the two probes.ResultsFourty-eight patients with malignant SPN were included (NCT01931579). The diagnostic accuracy for lung cancer using r-EBUS coupled with pCLE imaging was 79.2%. All the SPNs were successfully explored with either one of the probes (19 and 29 subjects for CholangioFlex and AlveoFlex, respectively). A specific solid pattern in the SPN was found in 30 pCLE explorations. Comparison between the two probes found no differences in the axial fibers thickness, cell size and specific solid pattern in the nodules. Extra-alveolar microvessel size appeared larger using CholangioFlex suggesting less compression effect. The kappa test for interobserver agreement for the identification of solid pattern was 0.74 (p = 0.001).ConclusionThis study demonstrates that pCLE imaging of SPNs is achievable in all segments of both lungs using either the 0.6mm or 1.4mm miniprobe.

Human epidermal growth factor receptor 2 (HER2) is involved in the malignant progression of several human cancers, including esophageal adenocarcinoma (EAC). The purpose of this study was to evaluate HER2 overexpression and to explore the feasibility of confocal laser endomicroscopy for in vivo molecular imaging of HER2 status in an animal model of Barrett's-related EAC. Rats underwent esophagojejunostomy with gastric preservation. At 30 weeks post-surgery, the esophagus of 46 rats was studied; endoscopic and histological findings were correlated with HER2 immunofluorescence on excised biopsies and gross specimens. At this age, 23/46 rats developed Barrett's esophagus (BE), and 6/46 had cancer (four EAC and two squamous cell carcinomas). A significant overexpression of HER2 was observed in esophageal adenocarcinoma compared with normal squamous esophagus (9.4-fold) and BE (6.0-fold). AKT and its phosphorylated form were also overexpressed in cancer areas. Molecular imaging was performed at 80 weeks post-surgery in four rats after tail injection of fluorescent-labeled anti-HER2 antibody. At this age, 3/4 rats developed advance adenocarcinoma and showed in vivo overexpression of HER2 by molecular confocal laser endomicroscopy with heterogeneous distribution within cancer; no HER2 signal was observed in normal or Barrett's tissues. Therefore, HER2 overexpression is a typical feature of the surgical induced model of EAC that can be easily quantified in vivo using an innovative mini-invasive approach including confocal endomicroscopy; this approach may avoid limits of histological evaluation of HER2 status on 'blinded' biopsies.

Erratum

A set of optical techniques for improving the diagnosis of early upper aerodigestive tract cancer

Confocal laser endomicroscopy

Confocal laser endomicroscopy (CLE) is an advanced endoscopic imaging technology that provides a magnified, cellular level view of gastrointestinal epithelia. In conjunction with topical or intravenous fluorescent dyes, CLE allows for an "optical biopsy" for real-time diagnosis. Two different CLE system have been used in clinical endoscopy, probe-based CLE (pCLE) and endoscope-based CLE (eCLE). Using pCLE, the device can be delivered: (I) into the luminal gastrointestinal tract through the working channel of standard endoscopes; (II) into extraluminal cystic and solid parenchymal lesions through an endoscopic ultrasound (EUS) needle; or (III) into the biliary system through an endoscopic retrograde cholangiopancreatography (ERCP) accessory channel. With eCLE, the probe is directly integrated into the tip of a conventional endoscope, however, these endoscopes are no longer commercially available. CLE has moderate to high diagnostic accuracy for neoplastic and inflammatory conditions through the gastrointestinal tract including: oesophageal, gastric and colonic neoplasia, pancreatic cysts and solid lesions, malignant pancreatobiliary strictures and inflammatory bowel disease. Some studies have demonstrated the diagnostic benefit of CLE imaging when combined with either conventional white light endoscopy or advanced imaging technologies. Therefore, optical biopsies using CLE can resolve diagnostic dilemmas in some cases where conventional imaging fails to achieve conclusive results. CLE could also reduce the requirement for extensive tissue sampling during surveillance procedures. In the future, CLE in combination with molecular probes, could allow for the molecular characterization of diseases and assess response to targeted therapy. However, the narrow field of view, high capital costs and specialized operator training requirements remain the main limitations. Future multi-center, randomized trials with a focus on conventional diagnostic applications, cost-effectiveness and standardized training will be required for definitive evidence. The objective of this review is to evaluate the technical aspects and current applications of CLE in patients with gastrointestinal and pancreatobiliary diseases and discuss future directions for this technique.

The majority of head and neck cancers are diagnosed at advanced tumor stages, which can limit treatment options and often increases the radicality of treatment. Evaluation of suspicious areas is usually performed with white light endoscopy, followed by invasive tissue biopsy as the gold standard of diagnosis. However, there is a significant diagnostic deficit in the early detection of precancerous lesions and the identification of tumor margins. To address this shortcoming, several optical methods have been developed and clinically tested in the upper aerodigestive tract over the past 20 years. Common to the optical diagnostic techniques is the ability to characterize epithelial tissue microarchitecture with the goal of visualizing and/or delineating tumors noninvasively and in real time to enable an optically guided, complete, and precise excision. These systems are based on the principle that the optical spectrum derived from any tissue contains information about the histological and biochemical nature of that tissue. Narrow-band imaging, contact endoscopy, confocal laser endomicroscopy, optical coherence tomography and Raman spectroscopy are some examples of such techniques that show promising results but have not yet reached widespread clinical application. The obvious advantages of making an accurate pathological diagnosis without the need to remove a tissue sample not only reduce trauma to the patient but would also have financial implications. The precise visualization of tumor margins, as well as more targeted biopsy sampling likewise represent promising developments.

Confocal Laser Endomicroscopy: Technical Advances and Clinical Applications

The problem of increasing the depth of light penetration in biotissues, which is solved by the use of immersion agents, including hyperosmotic ones, such as glucose, is urgent because of the significant development of optical technologies and methods used for non-invasive diagnostics of biotissues, as well as for clarifying the protocols of photodynamic therapy, photothermal destruction, optical biopsy, tomography, etc. In this case, it is important to determine the quantitative characteristics of the diffusion of immersion agents in biological tissues. In this work, the effective diffusion coefficient of 40% glucose solution in the human gum mucosa tissue has been determined in vitro, which was (4.1 ± 0.8) × 10–6 cm2/s. The method is based on the recording of the kinetics of changes in the diffuse reflectance spectra and the application of a free diffusion model.

Confocal laser endomicroscopy in Barrett's esophagus and endoscopically inapparent Barrett's neoplasia: a prospective, randomized, double-blind, controlled, crossover trial

Communication between neurosurgeons and pathologists is mandatory for intraoperative decision-making and optimization of resection, especially for invasive masses. Handheld confocal laser endomicroscopy (CLE) technology provides in vivo intraoperative visualization of tissue histoarchitecture at cellular resolution. The authors evaluated the feasibility of using an innovative surgical telepathology software platform (TSP) to establish real-time, on-the-fly remote communication between the neurosurgeon using CLE and the pathologist. CLE and a TSP were integrated into the surgical workflow for 11 patients with brain masses (6 patients with gliomas, 3 with other primary tumors, 1 with metastasis, and 1 with reactive brain tissue). Neurosurgeons used CLE to generate video-flow images of the operative field that were displayed on monitors in the operating room. The pathologist simultaneously viewed video-flow CLE imaging using a digital tablet and communicated with the surgeon while physically located outside the operating room (1 pathologist was in another state, 4 were at home, and 6 were elsewhere in the hospital). Interpretations of the still CLE images and video-flow CLE imaging were compared with the findings on the corresponding frozen and permanent H&E histology sections. Overall, 24 optical biopsies were acquired with mean ± SD 2 ± 1 optical biopsies per case. The mean duration of CLE system use was 1 ± 0.3 minutes/case and 0.25 ± 0.23 seconds/optical biopsy. The first image with identifiable histopathological features was acquired within 6 ± 0.1 seconds. Frozen sections were processed within 23 ± 2.8 minutes, which was significantly longer than CLE usage (p < 0.001). Video-flow CLE was used to correctly interpret tissue histoarchitecture in 96% of optical biopsies, which was substantially higher than the accuracy of using still CLE images (63%) (p = 0.005). When CLE is employed in tandem with a TSP, neurosurgeons and pathologists can view and interpret CLE images remotely and in real time without the need to biopsy tissue. A TSP allowed neurosurgeons to receive real-time feedback on the optically interrogated tissue microstructure, thereby improving cross-functional communication and intraoperative decision-making and resulting in significant workflow advantages over the use of frozen section analysis.

V12-02 CONFOCAL LASER ENDOMICROSCOPY FOR BLADDER CANCER DIAGNOSIS: HOW TO DO IT & OUR PRELIMINARY RESULTS