Das Nandan Kumar, Dey Rajib, Ghosh Nirmalya
Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, West Bengal, India.
J Biomed Opt. 2016 Sep 1;21(9):95004. doi: 10.1117/1.JBO.21.9.095004.
Spatial variation of refractive index (RI) in connective tissues exhibits multifractality, which encodes useful morphological and ultrastructural information about the disease. We present a spectral Mueller matrix (MM)-based approach in combination with multifractal detrended fluctuation analysis (MFDFA) to exclusively pick out the signature of the underlying connective tissue multifractality through the superficial epithelium layer. The method is based on inverse analysis on selected spectral scattering MM elements encoding the birefringence information on the anisotropic connective tissue. The light scattering spectra corresponding to the birefringence carrying MM elements are then subjected to the Born approximation-based Fourier domain preprocessing to extract ultrastructural RI fluctuations of anisotropic tissue. The extracted RI fluctuations are subsequently analyzed via MFDFA to yield the multifractal tissue parameters. The approach was experimentally validated on a simple tissue model comprising of TiO2 as scatterers of the superficial isotropic layer and rat tail collagen as an underlying anisotropic layer. Finally, the method enabled probing of precancer-related subtle alterations in underlying connective tissue ultrastructural multifractality from intact tissues.
结缔组织中折射率（RI）的空间变化呈现出多重分形特性，这编码了有关疾病的有用形态学和超微结构信息。我们提出了一种基于光谱穆勒矩阵（MM）并结合多重分形去趋势波动分析（MFDFA）的方法，以通过表层上皮层专门提取潜在结缔组织多重分形的特征。该方法基于对选定的光谱散射MM元素进行逆分析，这些元素编码了各向异性结缔组织的双折射信息。然后，对与携带双折射的MM元素对应的光散射光谱进行基于玻恩近似的傅里叶域预处理，以提取各向异性组织的超微结构RI波动。随后通过MFDFA对提取的RI波动进行分析，以得出多重分形组织参数。该方法在一个简单的组织模型上进行了实验验证，该模型由作为表层各向同性层散射体的TiO2和作为潜在各向异性层的大鼠尾胶原组成。最后，该方法能够从完整组织中探测潜在结缔组织超微结构多重分形中与癌前相关的细微变化。
