Optical coherence tomography (OCT) can perform high-speed, micron-level high resolution imaging of tissue
microstructures in vivo and in real time and can function as a type of optical biopsy to visualize the structural and functional
alterations associated with various diseases. The advances in endoscopic OCT and optical coherence microscopy
(OCM) provide an exciting avenue for many promising clinical applications with the potential of enhancing diagnostic
capabilities and treatment efficacies. In this review paper, we first review the basic principles for time- and Fourierdomain
OCT. We then survey the various endoscopic OCT technologies followed by the review of several representative
clinical applications using endoscopic OCT. Lastly, we discuss endoscopic-OCT-based, multi-modality imaging approaches
and their translational potentials.