Mueller Matrix has the potential to extract vital information regarding subtle morphological changes that appear
in human tissue in the early stages of cancer. In this report we have analyzed data of Muller Matrix imaging obtained
from human cervical tissue. The depolarization power quantifies the increase in density of cells in epithelium layer
during the progress of dysplasia. The early changes in dysplasia seen in the breakdown of ordered collagen fiber of the
stromal region result in changes in birefringence property. The retardance parameter of Mueller Matrix decomposition
displays these changes quantitatively.
Analysis of retardance images performed on measurements obtained from the stromal region shows significant
differences to discriminate dysplasia from normal tissue, where histopathology fails to diagnose. Further, the covariance
map of depolarization power and their highest eigenvector from the epithelial layer are able to grade the two different
stages of dysplastic conditions, grade I (GD1) and grade II (GD2) in human cervical tissue. This study can improve
sensitivity of detection in clinics as a supplementary technique to histopathology.
Optical techniques, especially the ones related to light scattering, has been seen to capture morphological changes,
such as increase in size and density of nuclei in cells. Mueller imaging of the epithelium and basal layer based on
polarized elastic scattering in human cervical tissue sections has been used to identify the dysplastic conditions
of the human cervix. The effect of dysplasia strongly manifests in the depolarization power and retardance,
which differs significantly in normal and dysplastic tissues sections. Principal Component Analysis (PCA) of the
depolarization power images derived from polar decomposition of Mueller matrices of 36 patients clearly identifies
the tissue region responsible for clear discrimination between the diseased and normal tissues. Significantly, the
principal components are found to be sensitive in discriminating normal cervical tissue and the two different
stages of dysplastic conditions grade I (GD1) and grade II (GD2) and provide cut-off depolarization values for
each of these stages.Though the depolarization values of GD1 are quite random as compared to normal and GD2
states, PCA is able to effectively separate it out by capturing subtle changes in the depolarization values.It is
worth noting that in the GD2 stage concentration of cells is high in the epithelial region near the basal layer than
the epithelium layer near the surface though this difference between these two regions is not as significant as in
GD1. Interestingly, this phenomenon is well reflected in the depolarization values, which PCA uses effectively
to segment GD1 and GD2 into different clusters. Retardance values show little variation along the stroma.
However, covariance matrix images of dysplastic and normal are able to capture depletion of retardance below
the basal layer due to progressive disruption of collagen network in dysplasia.
This study aims towards applying the intrinsic fluorescence technique, extracted from polarized fluorescence, to
detect subtle biochemical changes occurring during the progression of cancer from human cervical tissue samples. The
efficacy of this technique, earlier validated through tissue phantoms, is tested in human cervical tissues by comparing the
biochemical changes for diagnostic purpose at different wavelengths. It is pertinent to note that the co and crosspolarized
fluorescence do not display the high sensitivity obtained through extracted intrinsic fluorescence. We observed
that sensitivity and specificity of intrinsic fluorescence technique is high at 325 and 370nm for Collagen and NADH
respectively in comparison to 350nm excitation wavelength. It may be concluded that decoupled information at 325 and
370nm wavelengths for collagen and NADH respectively, through intrinsic fluorescence provides better diagnostic
parameter for early detection of cervical dysplasia. This information can provide a guiding path for designing a probe for
Mueller matrix has a vast application regarding information of any scattering (turbid) media such as fog, sea water, and biological tissues. It can extract information from scattering properties of the medium. Recently, information from Mueller images and their interpretation are being used for diagnostic purposes in biological tissues. Polar decomposition of Mueller matrices for scattering medium have also been developed, which could be a very powerful and sensitive tool for mapping the morphology of human tissue sections. On the basis of such decomposition, we report here the variation of diattenuation, depolarization and retardance from normal to dysplasia state in cervix tissue.
This study aims towards applying the intrinsic polarized fluorescence technique for obtaining valuable
information from human cervical tissue samples. The efficacy of this technique is tested in human tissues by comparing
its diagnostic capabilities with the bulk fluorescence. It is seen that biochemical information is hidden due to the
presence of distortions by tissue scattering and absorption in the fluorescence spectra. Intrinsic tissue fluorescence
provides a complete understanding of the biochemical and/or morphological changes that take place during the
progression of disease. Recording of the experimental data and thereafter subsequent extraction of the intrinsic
fluorescence serves as fingerprints towards determining the occurrence of these diseases.
Here we report a comparative study of intrinsic versus bulk polarized fluorescence in cervical tissues. Intrinsic
fluorescence is seen to be a more sensitive technique than bulk fluorescence for diagnosis of cervical cancers. Attempts
have been made to study the changes in the amount of different fluorophores found in the epithelial and stromal layer of
cervical tissue (both normal and cancerous). It has been seen that collagen decreases and NADH increases as a healthy
cervical tissue develops into a cancerous one. Intrinsic fluorescence provides more consistent discriminating results as
compared to bulk polarized fluorescence. It is also more sensitive in giving biochemical information from the different
layers in cervical tissue. It may be concluded that intrinsic fluorescence shows promise as a viable tool for providing
valuable insights towards fruitful diagnosis of the various stages of disease development and changes occurring with age.