Real-time delineation of basement membrane in human oral and esophageal mucosa with micro-optical coherence tomography

Basement membrane is a thin, extracellular matrix-like structure, separating the epithelium from the stroma and having a vital role in determining cancer progression. Identification of this diagnostically important structure with histology is invasive and labor-intensive. Micro-optical coherence tomography (µOCT) which has the capability to recognize subcellular-level microstructures underneath the surface offers the possibility to resolve basement membrane noninvasively in situ and in vivo. In this study, we conducted numerical analysis of the back-scattering intensity of basement membrane and experimental µOCT imaging of human labial mucosa in vivo and esophageal mucosa ex vivo, in an attempt to characterize the basement membrane underlying stratified squamous epithelial tissues. The results disclose that the layered structure of mucosa could be clearly delineated and the basement membrane presented as a steep, low-scattering linear structure in between the relatively high-scattering epithelium and stroma. Besides, according to the knowledges on its ultrastructure, we assume the low-scattering signal is collectively determined by basal lamina and reticular lamina since the former alone is extremely thin to be recognized by µOCT. This study clarifies the scattering features of basement membrane and the capability of real-time delineation of basement membrane which will help to determine the progression of epithelial cancers without the need of resection and histology.