Near infrared spectroscopy in optical coherence tomography

摘要

Optical coherence tomography (OCT) is a technique that is able to provide cross section views of tissue layers. This fast and non-invasive method is widely used in clinical applications for the diagnosis and treatment of certain diseases. Although conventional OCT is derived from the theory of interferometric imaging, emerging developments, including spectroscopic OCT and related techniques such as dual-band OCT and Raman spectroscopy-OCT, have resulted in significantly improved clinical capabilities for observing the tissue layers through enhanced tissue definition, image resolution, image contrast and scanning speed. This paper reviews the state-of-the-art developments of OCT. It starts with a general introduction of conventional interferometric OCT imaging methods including the time-domain and frequency-domain techniques. The second section explores the advances introduced from spectroscopy techniques in OCT, especially with spectroscopic OCT, dual-band OCT and Raman spectroscopy combined OCT. The final section discusses the current challenges in the application of approaches based on computer-aided diagnosis (CAD) for retinal imaging, for example automated segmentation of tissue layers and tracking disease progression. This task is currently limited by the quality of the recorded data from OCT systems but will be improved by adopting spectroscopic techniques. Finally, we analyse and discuss the improvements that are expected in retinal CAD from the adoption of newly emerging near infrared spectroscopy OCT at multiple wavelengths.