High Resolution Optical Imaging of the Esophagus Using the Nvision Volumetric Laser Endomicroscopy (VLE™) Imaging System

Inclusion Criteria: * Males and females over the age of 18 years. * Patients presenting for an EGD. * Ability to provide written, informed consent. * Females who are able to become pregnant, and are willing to take a pregnancy test. Exclusion Criteria: * Patients on anticoagulation undergoing high risk procedures in accordance to American Society For Gastrointestinal Endoscopy (ASGE) guideline for the management of antithrombotic agents for endoscopic procedures (2009)\*. * Patients with esophageal varices that preclude biopsies. * Presence of an esophageal mass that precludes full distention of the balloon from the NvisionVLE Catheter. * Patients with esophageal strictures that would prevent adequate expansion of the balloon from the NvisionVLE Catheter. * Patients with known inflammatory disease, esophageal tears or ulcers, which would prohibit full distention of the balloon from the NvisionVLE Catheter. * Patients with known eosinophilic esophagitis. * Patients that are pregnant. * Patients with a history of hemostasis disorders\*\*. * Patients on anticoagulation undergoing low risk procedures are not excluded. \*\*Hemostasis disorders will include, but will not be limited to: patients with hemophilia or other congenitally acquired clotting factor deficiencies, patients with cirrhosis with coagulopathy, patients known to have thrombocytopenia (\<100,000 plt/ul) and individuals with von Willibrand's disease or other known platelet malfunction disorders.