Identification and quantification of oral lymphatic vessel networks using optical coherence tomography (OCT).

Lymphatic vessels play essential roles in immune regulation and tissue homeostasis, yet their distribution within the oral mucosa is incompletely quantified due to the lack of noninvasive, depth-resolved imaging tools. In this study, optical coherence tomography (OCT) combined with an optimized optical attenuation coefficient estimation (OAC) was used to segment and quantify lymphatic vessel networks in healthy and ulcerated human oral mucosa. The results showed descriptive depth-related patterns across the three oral regions (lip, hard palate, and buccal mucosa). The lip showed an overall increase across the measured depth intervals; the hard palate remained consistently low in mean lymphatic density with little variation, whereas the buccal mucosa increased in superficial intervals and gradually decreased at greater depths. In ulcerative lesions, lymphatic density was lower within the ulcer region compared with the surrounding tissue in superficial and mid-depth layers, with this difference decreasing at greater depths. OCT angiography further demonstrated spatial parallelism between lymphatic vessel networks and blood vessels in both healthy and ulcerated tissues. These findings demonstrate that OAC-enhanced OCT enables non-invasive, depth-resolved visualization and quantification of oral lymphatic vessel networks, providing reference characteristics for normal oral mucosa and revealing region and pathology-associated lymphatic alterations relevant to inflammatory conditions and early pathological changes.