In vivo histology of Barrett's esophagus and associated neoplasia by confocal laser endomicroscopy

Background & Aims: Confocal laser endomicroscopy allows subsurface analysis of the intestinal mucosa and in vivo histology during ongoing endoscopy. Here, we have applied this technique to the in vivo diagnosis of Barrett's epithelium and associated neoplasia. Methods: Fluorescein-aided endomicroscopy was performed by applying the endomicroscope over the whole columnar-lined lower esophagus. Images obtained within 1 cm of the columnar-lined lower esophagus were stored digitally and a targeted biopsy examination or endoscopic mucosal resection of the examined areas was performed. In vivo histology was compared with the histologic specimens. All digitally stored images were re-assessed by a blinded investigator by the confocal Barrett classification system to predict histology. Intraobserver and interobserver variations of the involved endoscopists were evaluated by using K statistics. Results: Endomicroscopy allowed distinguishing between different types of epithelial cells and detected cellular and vascular changes in Barrett's epithelium at high resolution during ongoing endoscopy in 63 patients. Barrett's esophagus and associated neoplasia could be predicted with a sensitivity of 98.1% and 92.9% and a specificity of 94.1% and 98.4%, respectively (accuracy, 96.8% and 97.4%). The mean kappa value for interobserver agreement for the prediction of histopathological diagnosis was .843, whereas the intraobserver agreement showed a mean kappa value of .892. Conclusions: Fluorescence-aided endomicroscopy of Barrett's esophagus allows in vivo histology of the mucosal layer during ongoing endoscopy. Gastric and Barrett's epithelium and Barrett's-associated neoplastic changes can be diagnosed with high accuracy. Thus, endomicroscopy may be helpful in the management of patients with Barrett's esophagus.