Identification of the layered morphology of the esophageal wall by optical coherence tomography

AIM:To assess each layer of the optical coherence tomography(OCT)image of the esophageal wall with reference to the histological structure. METHODS:Resected specimens of fresh pig esophagus was used as a model for the esophageal wall.We injected cyanoacrylate adhesive into the specimens to create a marker,and scanned them using a miniature OCT probe.The localization of these markers was assessed in the OCT images.Then we compared the OCT-imaged morphology with the corresponding histological section,guided by the cyanoacrylate adhesive markers.We prepared a second set of experiments using nylon sutures as markers. RESULTS:The OCT image of the esophageal specimen has a clear five-layered morphology. First,it consisted of a relatively less reflective layer; second,a more reflective layer;third,a less reflective layer;fourth,a more reflective layer;and fifth,a less reflective layer.Comparing the OCT images with marked histological sections showed that the first layer corresponded to stratified squamous epithelium; the second to lamina propria;the third to muscularis mucosa;fourth,submucosa;and fifth,muscularispropria with deeper structures of the esophageal wall.CONCLUSION:We demonstrated that the OCT image of the normal esophageal wall showed a five- layered morphology,which corresponds to histological esophageal wall components.