A fluorescence endomicroscopy for in vivo microscopy of the upper-and the lower GI tract
ABSTRACT This report describes the development and the clinical evaluation of a novel confocal endomicroscope for obtaining fluorescence images of cellular morphology of the mucosae of the upper- and the lower-GI tract in vivo. The work assessed the feasibility of performing in vivo microscopy at endoscopic examination and evaluated fluorescence imaging protocols.
Images were collected in real time by using two prototype endoscope configurations, featuring slightly different miniaturized fiber-optic confocal microscopes, fitted integrally into the tips of conventional endoscopes. Confocal scanning was performed at 488 nm illumination for excitation of exogenously applied fluorophores (topical acriflavine and intravenous fluorescein). The images were compared with conventional histology of biopsy specimens and the findings of white-light endoscopy.
Confocal endomicroscopy enabled imaging of cellular and subcellular structures (i.e., nuclei) of the GI tract. The crypts of the colonic mucosa, the villi of the terminal ileum and duodenum, the gastric pits of the stomach, and the squamous epithelium of the distal esophagus could be clearly visualized. Acriflavine strongly contrasted the cell nuclei of the surface epithelium, including the absorptive epithelial cells and the mucous secreting goblet cells. Fluorescein stained the extracellular matrix of the surface epithelium and also the subepithelial layers of the lamina propria. Images at increasing depth beneath the epithelium showed the mucosal capillary network. The findings correlated with the histology of biopsy specimens.
The development of a fluorescence confocal endomicroscope makes it practical to examine the upper- and the lower-GI mucosa in cellular detail during otherwise routine endoscopic examination. The results represent a major technical advance in the development of this new optical imaging modality for the in vivo examination of GI tissue.
- SourceAvailable from: Sung-Liang Chen
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- "Besides, the focusing and scanning should better be implemented at the distal end of a probe, which is usually a few millimeters in diameter in order to fit the requirements for endoscopy. In confocal microscopy, the use of piezoelectric actuator to physically deflect the tip of an optical fiber has been demonstrated . This method for mechanical scanning at the distal of a probe, however, imposes difficulties on miniaturization. "
ABSTRACT: Imaging of the cells and microvasculature simultaneously is beneficial to the study of tumor angiogenesis and microenvironments. We designed and built a fiber-optic based photoacoustic microscopy (PAM) and confocal fluorescence microscopy (CFM) dual-modality imaging system. To explore the feasibility of this all-optical device for future endoscopic applications, a microelectromechanical systems (MEMS) scanner, a miniature objective lens, and a small size optical microring resonator as an acoustic detector were employed trying to meet the requirements of miniaturization. Both the lateral resolutions of PAM and CFM were quantified to be 8.8 μm. Axial resolutions of PAM and CFM were experimentally measured to be 19 μm and 53 μm, respectively. The experiments on ex vivo animal bladder tissues demonstrate the good performance of this system in imaging not only microvasculature but also cellular structure, suggesting that this novel imaging technique holds potential for improved diagnosis and guided treatment of bladder cancer.Photoacoustics 05/2013; 1(2):30–35. DOI:10.1016/j.pacs.2013.07.001 · 4.60 Impact Factor
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- "A plasma concentration of fluorescein in the vicinity of 20 mg/L was able to provide adequate fluorescent contrast. In people, the duration of effect for CEM procedures has been subjectively assessed and appears variable, lasting from 30 to 60 min based on previous reports (Polglase et al., 2005; Becker et al., 2008). As the procedure progresses, however, the signal-to-noise ratio appears to increase such that a significant decrease in image resolution and therefore quality occurs (Becker et al., 2008). "
ABSTRACT: This study described the pharmacokinetics of the intravenous fluorophore, fluorescein, and aimed to evaluate its utility for use in upper gastrointestinal confocal endomicroscopy (CEM). Six healthy, mature, mixed-breed dogs were anesthetized and then dosed intravenously with fluorescein at 15 mg/kg. Blood samples were collected at predetermined time-points. Dogs were examined by upper gastrointestinal confocal endomicroscopy and monitored for adverse effects. Plasma fluorescein concentrations were measured using high-performance liquid chromatography (HPLC) with UV/Vis detection. Mean plasma concentration at 5 min was 57.6 ± 18.2 mg/L, and plasma concentrations decreased bi-exponentially thereafter with a mean concentration of 2.5 mg/L ± 1.26 at 120 min. Mean terminal plasma elimination half-life (t(½β) ) was 34.8 ± 8.94 min, and clearance was 9.1 ± 3.0 mL/kg/min. Apparent volume of distribution at steady-state was 0.3 ± 0.06 L/kg. Fluorescein provided optimal fluorescent contrast to enable in vivo histologically equivalent evaluation of topologic mucosal morphology within the first 30 min following intravenous administration. Adverse effects were not observed. Based upon the calculated clearance, a constant rate infusion at a rate of 0.18 mg/kg/min is predicted to be adequate, following an initial loading dose (2 mg/kg), to maintain plasma concentration at 20 mg/L for optimal CEM imaging during the study period.Journal of Veterinary Pharmacology and Therapeutics 12/2012; 36(5). DOI:10.1111/jvp.12031 · 1.32 Impact Factor
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- "La fluorescéine sodique présente l'avantage de mettre en évidence des structures situées sous la surface épithéliale, au niveau de la lamina propria. Cependant, en raison de ses propriétés pharmacocinétiques, ce marqueur ne montre pas les noyaux cellulaires . Or, l'examen des noyaux cellulaires est d'une importance majeure dans le classement des grades de néoplasie. "
ABSTRACT: Staining techniques currently used during endomicroscopic procedures do not allow in vivo differentiation between grades of intraepithelial neoplasia. This information is essential because it informs the degree of malignancy of the lesion and determines the most appropriate therapeutic treatment. The use of the Cellvizio®GI system (Mauna Kea Technologies, Paris, France) allowed us to report here a series of observations relating to the size of colonic glands, and their layout on epithelial surface. These quantitative data were determined thanks to the analysis of several images mosaics from normal mucosa, hyperplastic polyps, and tubular adenoma. Our results showed that the glandular diameter and spacing had different features according to the histology and the grade of intraepithelial neoplasia.IRBM 12/2012; 33(s 5–6):330–337. DOI:10.1016/j.irbm.2012.09.003 · 0.38 Impact Factor