The goal of this research is to follow Barrett's Esophagus participants for 3 years using the tethered capsule endomicroscopy device with distal scanning and a compact imaging system in a multi-site clinical study.

The progression of Barrett's Esophagus will be studied over time using tethered capsule endomicroscopy imaging and will be performed at 5 different clinical centers in the US, namely: Massachusetts General Hospital (MGH),(MA), Mayo Clinic Jacksonville (FL), Mayo Clinic Rochester (MN), Columbia University Medical Center (NY), Kansas City VA Medical Center (MO). MGH will be the coordinating center of this multicenter study. Dr G. Tearney will serve as study Sponsor Investigator.

The purpose of this study is to determine the natural history of Barrett's Esophagus using TCE in participants diagnosed with Barrett's Esophagus and undergoing surveillance endoscopy.

Inclusion Criteria:

• Participants over the age of 18
• Participants who are capable of giving informed consent
• Participants with a diagnosis of BE without high grade dysplasia, intramucosal adenocarcinoma or esophageal adenocarcinoma, confirmed by endoscopic biopsy
• Participants who had or will have a standard of care EGD within 15 months, exceptions to this can be submitted to the coordinating center (MGH) for approval

Exclusion Criteria:

• Participants with prior endoscopic ablation or resection treatment of BE at enrollment visit
• Participants with esophageal fistula and/or esophageal strictures
• Participants with the inability to swallow capsules
• Concomitant chemotherapy treatment
• Self reported pregnancy