Gujarat University, C.U. Shah Science College, Ahmedabad-380 009, India.
J Biomed Opt. 2011 Aug;16(8):087003. doi: 10.1117/1.3606563.
Using the multiresolution ability of wavelets and effectiveness of singular value decomposition (SVD) to identify statistically robust parameters, we find a number of local and global features, capturing spectral correlations in the co- and cross-polarized channels, at different scales (of human breast tissues). The copolarized component, being sensitive to intrinsic fluorescence, shows different behavior for normal, benign, and cancerous tissues, in the emission domain of known fluorophores, whereas the perpendicular component, being more prone to the diffusive effect of scattering, points out differences in the Kernel-Smoother density estimate employed to the principal components, between malignant, normal, and benign tissues. The eigenvectors, corresponding to the dominant eigenvalues of the correlation matrix in SVD, also exhibit significant differences between the three tissue types, which clearly reflects the differences in the spectral correlation behavior. Interestingly, the most significant distinguishing feature manifests in the perpendicular component, corresponding to porphyrin emission range in the cancerous tissue. The fact that perpendicular component is strongly influenced by depolarization, and porphyrin emissions in cancerous tissue has been found to be strongly depolarized, may be the possible cause of the above observation.
利用小波的多分辨率能力和奇异值分解（SVD）的有效性来识别统计稳健的参数，我们在不同尺度下（人类乳房组织）找到了许多局部和全局特征，这些特征可以捕捉到共极化和交叉极化通道中的谱相关性。共极化分量对固有荧光敏感，在已知荧光团的发射域中，对正常、良性和癌组织表现出不同的行为，而垂直分量更容易受到散射的扩散效应的影响，这表明在主成分中使用核平滑密度估计时，恶性、正常和良性组织之间存在差异。SVD 中相关矩阵的主要特征值对应的特征向量，在三种组织类型之间也表现出显著差异，这清楚地反映了光谱相关行为的差异。有趣的是，最显著的区别特征表现在垂直分量上，这与癌组织中卟啉的发射范围相对应。垂直分量受去偏振强烈影响，而癌组织中的卟啉发射被发现强烈去偏振，这可能是上述观察结果的可能原因。
