Optical Microangiography: High-Definition Magnification Colonoscopy with Narrow Band Imaging (NBI) for Visualizing Mucosal Capillaries and Red Blood Cells in the Large Intestine

BACKGROUND/AIMS: Recent advances in zoom endoscopy have enabled the subepithelial capillary network (SECN) in different organs of the gastrointestinal tract to be visualized. Ex vivo studies have suggested that the SECN demonstrates a honeycomb-like structure in the large intestine, but this has not yet been visualized in vivo. The high clarity and resolution of narrow-band imaging (NBI) may allow visualization at the single red-blood-cell (RBC) level and more accurate visualization of the SECN. We investigated whether high-definition magnification colonoscopy with NBI is useful for visualizing capillaries and RBCs in the large intestine. METHODS: Sixteen patients with bowel symptoms undergoing routine colonoscopy with normal findings in a tertiary referral academic gastroenterology and endoscopy unit were included in the study. Total colonoscopies were performed using a high-definition magnification colonoscope (CF-H260AZI, Olympus, Tokyo) and a prototype high-definition electronic endoscopy system capable of NBI. Each part of the large intestine (cecum, ascending, transverse, descending, and sigmoid colon, and rectum) was observed at the maximum magnification with white-light imaging (WLI) and NBI. The normal honeycomb-like SECN and RBC movement by high-definition magnification colonoscopy with either WLI or NBI was prospectively successfully visualized for each part of the large intestine. RESULTS: In all subjects, high-definition magnification colonoscopy with NBI allowed the visualization of a honeycomb-like SECN together with RBC movement in each segment of the large intestine except for the rectum. In contrast, with WLI alone, neither this SECN structure nor RBC movement could be detected. CONCLUSIONS: High-definition magnification colonoscopy with NBI could be a new optical method for facilitating noninvasive investigations of both the microvascular architecture and microcirculation without the need for contrast materials.

Barrett's Esophagus: Diagnosis, Screening, Surveillance, and Controversies

Barrett's esophagus (BE) is a frequent complication of gastroesophageal reflux disease, an acquired condition resulting from persistent mucosal injury to the esophagus. The incidence of Barrett's metaplasia and Barrett's adenocarcinoma has been increasing, but the prognosis of Barrett's adenocarcinoma is worse because individuals present at a late stage. Attempts have been made to intervene at early stage using surveillance programmes, although proof of efficacy of endoscopic surveillance is lacking. There is much to be learned about BE. Whether adequate control of gastroesophageal reflux early in the disease alters the natural history of Barrett's change once it has developed remains unanswered. Thus there is great need for carefully designed large randomised controlled trials to address these issues in order to determine how best to manage patients with BE. The AspECT and BOSS clinical trials proride this basis.