Detection of Buried Barrett’s Glands after Radiofrequency Ablation with Volumetric Laser Endomicroscopy; a Histology Correlation Pilot Study

BACKGROUND: The prevalence and clinical relevance of Buried Barrett’s (BB) epithelium after radiofrequency ablation (RFA) in Barrett’s esophagus (BE) is questioned. Recent studies using small optical coherence tomography (OCT) catheters for scanning underneath the neosquamous epithelium demonstrated a high prevalence of tissue structures that might correspond to BB. Histological correlation, however, is lacking. Volumetric Laser Endomicroscopy (VLE) is a novel balloon-based OCT imaging technique that provides a 6-cm long circumferential volumetric scan of the esophageal wall layers to a depth of 3 mm with a resolution comparable to low-power microscopy. AIM: To evaluate if post-RFA subsquamous structures, detected with VLE, actually correspond to BB and to pursue direct histological correlation of VLE images. METHODS: In-vivo VLE was performed to detect subsquamous structures suspicious for BB in patients with 100% endoscopic regression of dysplastic Barrett’s epithelium after RFA. Areas with suspicious subsquamous VLE structures were marked with electrocoagulation after which in-vivo VLE was repeated to confirm that the correct area was demarcated. These areas were subsequently resected endoscopically, followed by immediate ex-vivo VLE scanning to reconfirm the presence of the subsquamous VLE structures. Extensive histological sectioning was then performed and all histopathology slides were evaluated by an expert BE pathologist (blinded for VLE images). RESULTS: In 9 patients, 6 areas with suspicious subsquamous structures were seen on in-vivo VLE and resected. Ex-vivo VLE of these 6 ER specimens reconfirmed the presence of these subsquamous structures in 5 ER specimens. Extensive histological sectioning of these areas showed BB in one area. The other subsquamous VLE structures corresponded to dilated (ducts of) (sub)mucosal glands or blood vessels. CONCLUSION: VLE may potentially detect BB under endoscopically normal appearing neosquamous epithelium. However, most post-RFA subsquamous structures identified by in-vivo VLE did not correspond to BB. Further studies are required to identify VLE features that allow for differentiation of BB from normal subsquamous structures.