This study will collect data from patients routinely undergoing a endoscopic surveillance and Cellvizio endomicroscopy procedure due to confirmed Barrett's esophagus. The objective is to determine if endomicroscopy images collected using the marketed Cellvizio device may help endoscopists more accurately diagnose, in conjunction with traditional tissue sampling techniques, whether a suspected lesion is malignant or benign.

This is a longitudinal observational study were imaging procedures are allocated in a random order to directly address the low sensitivity and specificity of enhanced macroscopic endoscopic imaging devices by determining whether probe-based Confocal Laser Endomicroscopy (pCLE), as a supplement to Narrow Band Imaging (NBI) can further improve sensitivity and specificity to a level that would be acceptable to avoid random biopsy, and better direct biopsy of suspicious areas. The study is also addressing pCLE as a supplement to standard white light endoscopy and random biopsy alone. In fact, the study is powered to evaluate per lesion sensitivity and specificity of confocal imaging as applied to lesions identified by white light endoscopy. Therefore, the study addresses the shortcomings of standard white light endoscopy (high number of random biopsies, less than ideal directed biopsy of suspicious areas) and the primary shortcomings of Narrow Band Imaging (NBI) (low specificity with resultant high false positives, again resulting in many unnecessary biopsies).

Inclusion Criteria:

1. Patients with documented or suspected Barrett's esophagus presenting for endoscopy
2. Age > 18 years
3. Ability to provide written, informed consent

Exclusion Criteria:

1. Presence of erosive esophagitis
2. Inability to obtain biopsies due to anticoagulation, varices, etc.
3. Allergy to fluorescein, pregnancy
4. Presence of an esophageal mass other than small 10mm or less nodules
5. Renal insufficiency