A pilot study of the feasibility of confocal endomicroscopy for examination of the human airway.

BACKGROUND: Traditional methods of evaluating human airway histology, such as surgical biopsy or endobronchial biopsy, are limited by the risks associated with these tissue-sampling procedures. OBJECTIVE: The purpose of this study was to develop and evaluate the first confocal endomicroscope for real-time, in vivo imaging of human respiratory mucosa in a clinical setting. METHODS: A confocal endomicroscope prototype was designed using Pentax bronchoscope parts (EB1970K). Airways of adult patients (N=5) undergoing rigid bronchoscopy for various clinical indications were imaged with the confocal endomicroscope after intravenous administration of fluorescein sodium. The device was introduced into the airways through the rigid bronchoscope. Images were collected from the trachea, primary and secondary carinae, and any endobronchial mass. The images were compared with those obtained from histologic sections from conventional endobronchial biopsies. RESULTS: Confocal endomicroscopy provided real-time images of the cellular and subcellular structures of the respiratory mucosa and submucosa in vivo. The pseudostratified columnar epithelium (including columnar cells and goblet cells) could be visualized. Images obtained at increasing depth showed the lamina propria and microvasculature. Longitudinal folds in the mucosa enabled imaging in cross-section, showing alignment of epithelial cells along the basement membrane and cilia on the surface of the cells. Below the epithelium, the smooth muscle could be identified. In images from a patient with an endobronchial adenocarcinoma, confocal imaging could distinguish between a normal airway epithelium and malignant tissue. CONCLUSIONS: Confocal endomicroscopy is a feasible method for analyzing human airway wall architecture and endobronchial abnormalities in histologic detail in vivo.

Confocal endomicroscopy: a novel imaging technique for in vivo histology of cervical intraepithelial neoplasia.

Optical imaging technologies, such as reflectance and fluorescence spectroscopy, have shown the potential to provide enhanced detection of changes in the uterine cervix at clinical examination. This review focuses on fluorescence confocal endomicroscopy that enables in vivo microscopic imaging of the cervical epithelium in histological detail in real time. The microscopic imaging technique may permit 'see-and-treat' workflows in colposcopy through high-resolution fluorescence imaging of cellular and subcellular detail from the surface and subepithelial layers of the cervical mucosa. The device may be used in conjunction with a conventional colposcope. Preliminary data from clinical studies suggest that the device can be used to visualize features of the cervical epithelium including the squamo-columnar junction, dermal papillae and endocervical glands. Moreover, the technique has the ability to detect and grade precancerous changes of the cervical epithelium in conditions, such as cervical intraepithelial neoplasia, where prediction using colposcopy may be problematic. The early detection and diagnosis of gynecological abnormalities through the collection of 'optical' biopsies or targeted mucosal excisional biopsies have the potential to improve patient management through early therapeutic intervention and 'see-and-treat' strategies.

Pentax confocal endomicroscope: a novel imaging device for in vivo histology of the upper and lower gastrointestinal tract.

With advances in endoscopic imaging tools, it is becoming increasingly possible to find, assess and treat numerous gastrointestinal (GI) pathologies at the time of endoscopy. This article focuses on the newly developed Pentax confocal endomicroscope that enables in vivo microscopic imaging of the upper and lower GI tract in histological detail at the time of patient examination without the collection of biopsies. The optical imaging technique has the potential to revolutionize clinical workflows in endoscopy through high-resolution fluorescence imaging of cellular and subcellular detail from the surface and subepithelial layers of the GI mucosa. The device incorporates a full screen, high-resolution charge coupled device as well as a confocal microscope. Preliminary data from blinded clinical studies suggests that the use of this device can increase the diagnostic yield for disease detection in conditions such as ulcerative colitis and Barrett's esophagus, where diagnosis using white light endoscopy is problematic. The early detection and diagnosis of GI abnormalities through the collection of 'optical' biopsies or targeted mucosal excisional biopsies has the potential to improve patient outcomes and enable early therapeutic intervention.

Detection of morphological changes of the ovine cervix in response to sex steroids using a fluorescence confocal endomicroscope.

OBJECTIVE: This study examined morphological changes of the ovine cervix in response to sex steroids using confocal microscopy. STUDY DESIGN: Experimental animals were ovariectomized, and the hormonal status of 4 groups of ewes (n = 5) was manipulated using sex steroids (no replacement, estradiol, progesterone, estradiol, and progesterone). The results were correlated with control ewes (n = 7) in naturally occurring reproductive states (estrus and midluteal). RESULTS: Plasma progesterone concentrations of experimental animals were comparable with those observed during normal reproduction. Confocal microscopy enabled subcellular resolution of the cervical epithelium and the detection of morphological changes associated with alterations in progesterone and estradiol in both artificially manipulated and naturally cycling ewes. Differences in nuclear size, distribution, and density could be differentiated in confocal images and histologic sections of ectocervix from animals in estrus and in the presence of exogenous estradiol. CONCLUSION: Confocal microscopy has potential diagnostic value for the detection of cellular and subcellular changes of the cervical epithelium.

A fluorescence confocal endomicroscope for in vivo microscopy of the upper- and the lower-GI tract.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

In vivo detection of morphological and microvascular changes of the colon in association with colitis using fiberoptic confocal imaging (FOCI).

Using a well-established rodent model of inflammatory bowel disease (IBD), the present study examined changes in the microvasculature of the colonic mucosa in association with ulcerative colitis (UC). The results were compared to microscopic alterations in tissue morphology to establish a temporal relationship between microcirculatory dysfunction and IBD pathology. Mild colitis was induced in rats by the oral consumption of 5% dextran sulfate sodium (DSS) in drinking water. Control animals were provided with water ad libitum. After 3, 5, and 7 days of oral ingestion of DSS, anesthetized rats were laparotomized. The mucosal surface of the distal colon was then examined using fiber optic confocal imaging (FOCI; excitation 488 nm argon ion laser, detection above 515 nm). Changes in the mucosal architecture were examined following the topical application of the fluorescent dye, tetracycline hydrochloride. Tetracycline hydrochloride, an antibiotic used widely in clinical medicine, enabled imaging of the crypts at the surface of the mucosa. Spatial changes in the microvascular structure were assessed following the intravenous administration of fluorescein isothiocyanate dextran (FITC-dextran). Confocal images were correlated with clinical parameters, including weight loss, occult blood, and stool consistency. Attenuation of the colonic epithelium was detected on day 3 colitis. Morphological changes including crypt loss, crypt distortion, and inflammatory cell infiltrate were detected on day 5 and day 7 colitis. Dual channel imaging showed the mucosal capillary network outlining the stromal confines of the mucus-secreting glands in control tissue. Experimental colitis resulted in diffuse hypervascularity and tortuosity of the capillary vessels. Evidence of increased vessel leakiness (leakage of FITC-dextran from the lumen) was first detected on day 5 colitis. Complete disruption of the normal honeycomb pattern of the vessels and capillary dilation was evident after 7 days of DSS ingestion. These findings suggest that the pathogenesis of ulcerative colitis is associated with changes in the vascular architecture as demonstrated in vivo using confocal microscopy.