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.
Polglase
Adrian L
AL
Cabrini Monash University Department of Surgery, Cabrini Medical Centre, Malvern, Victoria, Australia.
McLaren
Wendy J
WJ
Skinner
Stewart A
SA
Kiesslich
Ralf
R
Neurath
Markus F
MF
Delaney
Peter M
PM
D000167:Acriflavine; D000368:Aged; D000369:Aged, 80 and over; D003113:Colonoscopy; D020776:Endoscopes, Gastrointestinal; D016099:Endoscopy, Gastrointestinal; D005260:Female; D005336:Fiber Optic Technology; D019793:Fluorescein; D005456:Fluorescent Dyes; D005753:Gastric Mucosa / Q000166:cytology; D005773:Gastroscopy; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology; D008297:Male; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D008904:Miniaturization; D055100:Optical Fibers
D005456:Fluorescent Dyes; D000167:Acriflavine; D019793:Fluorescein