Endoscopic Optical Coherence Angiography Enables 3-Dimensional Visualization of Subsurface Microvasculature

Abstract

Endoscopic imaging technologies such as confocal laser endomicroscopy and narrow band imaging (NBI) have been used to investigate vascular changes as hallmarks of early cancer in the gastrointestinal tract. However, the limited frame rate and field of view make confocal laser endomicroscopy imaging sensitive to motion artifacts, whereas NBI has limited resolution and visualizes only the surface vascular pattern. Endoscopic optical coherence tomography (OCT) enables high-speed volumetric imaging of subsurface features at near-microscopic resolution, and can image microvasculature without exogenous contrast agents, such as fluorescein, which obliterates the image in areas of bleeding, or after biopsies and resections. OCT has been used for visualizing microvasculature in small animal models and larger vasculature in swine; however, the speed, resolution, and stability of previous systems were not sufficient for 3-dimenstional visualization of microvasculature in endoscopic clinical applications. Herein, we have presented an ultra–high-speed endoscopic OCT technology that achieves >10 times faster imaging speed than commercial systems and high frame-to-frame stability, enabling OCT angiography in the human gastrointestinal tract. Endoscopic OCT angiography of normal esophagus, nondysplastic Barrett’s esophagus (BE) and normal rectoanal junction are demonstrated.