Confocal endomicroscopy: a novel application for imaging of oral and oropharyngeal mucosa in human

Confocal endomicroscopy is an emerging technique for intravital visualization of neoplastic lesions, but its use has so far been limited to the gastrointestinal (GI) tract. This study was designed to assess the feasibility of in vivo confocal endomicroscopy of different regions of the oropharyngeal mucosa and to evaluate different contrast agents. We examined five different regions of the human oropharynx in vivo, and images were collected in real time by using a confocal laser endoscope as formerly described for the GI tract. Additionally ex vivo specimens were examined using a topical contrast agent. Confocal scanning was performed at 488-nm illumination for excitation of exogenously applied fluorophores (topical acriflavine and intravenous fluorescein). Confocal endomicroscopy allowed for visualization of cellular and subcellular structures of the anterior human oropharyngeal region. Fluorescein staining yielded architectural details of the surface epithelium and also subepithelial layers. Images taken at increasing depth beneath the epithelium showed the mucosal capillary network. Acriflavine strongly contrasted the cell nuclei of the surface epithelium. The findings correlated well with the histology of biopsy specimens. This is the first report showing that the use of fluorescence confocal endomicroscopy represents a promising method to examine cellular details in vivo in different oropharyngeal regions in human.