The second part travels to the sample tissue. One part of the light wave travels to a reference mirror, where it reflects directly back towards the beam splitter. The light wave reaches a beam splitter or a partial mirror, which splits the light wave in half. A light source emits a low-coherence, laser light wave. The physics principle that allows the filtering of scattered light is optical coherence. The wavelength used is around 1300 nm to minimize energy absorption in the light beam caused by protein, water, haemoglobin and lipids. OCT uses low coherent near infrared light. Physical principles and acquisition systems The critical advantage of OCT over ultrasonography and magnetic resonance imaging is due to its micrometer resolution (about 10–15 μm of tissue axial resolution). OCT is based on near infrared light an optical beam is directed at the tissues, most of the light scatters and only the small portion of this light that reflects from subsurface features is collected and forms the image by yielding spatial information about tissue microstructure. in 1991 in vitro on the human peripapillary region of the retina and coronary arteries. Optical coherence tomography (OCT) is a new imaging modality, used for the first time by Huang et al. Dans cet article, on discute les principes physiques en discutant l’ancienne et la nouvelle génération de tomographie par cohérence optique, time domain et Fourier domain respectivement. La tomographie par cohérence optique est une modalité d’imagerie récente endocoronaire utilisant la lumière infrarouge, caractérisée par une haute résolution. We will review the physical principles, including the old time domain and newer Fourier domain generations, clinical applications, controversies and perspectives of optical coherence tomography. Optical coherence tomography is a new endocoronary imaging modality employing near infrared light, with very high axial resolution.

Optical coherence tomography principle