Optical coherence tomography in the gastrointestinal tract

Optical coherence tomography (OCT) is a high-resolution, cross-sectional op tical imaging technique that allows in situ imaging of tissue by measuring back-reflected light, OCT provides images in real time with a resolution ap proaching that of conventional histopathology; but without the need for tis sue removal. OCT imaging can be performed endoscopically to visualize gastr ointestinal tissue using a fiberoptic catheter passed through the instrumen t channel of a conventional endoscope. The resolution of OCT allows visuali zation of the different layers of gastrointestinal epithelium and the diffe rentiation of Barrett's epithelium from normal gastric and squamous mucosa, OCT has also been used to image esophageal adenocarcinoma and colonic poly ps. Recent developments include Doppler OCT, spectroscopic OCT, and ultrahi gh-resolution OCT, which can visualize nuclei within single tells, Although still in its infancy as a clinical tool, OCT currently provides high-resol ution images over the same imaging depth as conventional mucosal biopsy, an d may Drove to be a useful and minimally invasive technique for evaluating gastrointestinal tissue, particularly for early neoplastic changes.