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

To assess each layer of the optical coherence tomography (OCT) image of the esophageal wall with reference to the histological structure.

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.

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, muscularis propria with deeper structures of the esophageal wall.

We demonstrated that the OCT image of the normal esophageal wall showed a five-layered morphology, which corresponds to histological esophageal wall components.