Fourier spectrum analysis of full-field optical coherence tomography for tissue imaging

Quantifying structural features and their changes of live intact cells and tissues in three dimensions at micrometre or submicrometre levels is very helpful for accurate disease diagnosis at the early phase. Thus, several quantitative measures of tissue structures have been proposed which may be divided into two categories: one is geometrical or morphological measures such as layer thickness, the size distribution of the spatially resolved microscopic structures in the optical sectional images at various depth positions; and the other is parameters that describe various statistical characteristics of light scattering of tissues, including the values of the scattering coefficient and the anisotropy factor. The values of these measures may be obtained by light-scattering spectroscopyor imaging-based techniques. The highresolution optical sectioning capability of full-field optical coherence tomography (FFOCT) makes it possible to visualize the intact, in situ live tissue and locally quantify tissue structures and their changes [1–17]. The advantage of visualizing intact live tissue over the sliced stained tissue observation in traditional microscopy is that more accurate information about tissue structure and the relationship between tissue elements may be provided because of the absence of freezing artefacts. FFOCT is a development of the full-field low coherence interference microscopy and the imaging