Fluorescence Mueller matrix imaging of the stromal region in unstained cervical tissue sections: quantitative categorization of CIN grades
This study introduces a fluorescence Mueller matrix imaging system coupled with an appropriate analysis method for assessing anisotropy in the stromal regions of human ectocervical tissue sections. The system effectively captures detailed changes in tissue morphology and biochemistry, driven by interactions between intrinsic fluorophores and their microenvironment. Measurements from the connective tissue near the epithelium reveal significant alterations in fluorescence diattenuation and polarizance in both ground and excited states. Pronounced differences in the decomposition-derived anisotropy parameters are observed for unstained cervical tissue sections varying from healthy to different grades of cervical intraepithelial neoplasia (CIN). A significant reduction in the parameters—circular depolarization (M44 decreases from 0.65 in healthy tissue to 0.05 in CIN-III), fluorescence linear diattenuation (α L drops from 0.25 to 0.07), and fluorescence linear polarizance (β L drops from 0.27 to 0.08)—is observed due to the degradation of the collagen fibrous structure present within the stromal region of the human cervix. The polarization parameters demonstrate a linear relationship between healthy and different CIN grades as the cancer progresses. Additionally, a strong correlation was identified between α L and β L , confirmed through linear curve fitting across all sites examined at different CIN grades. This fluorescence Mueller matrix imaging technique, coupled with a suitable decomposition method, serves as a diagnostic tool that minimizes the need for extensive clinical tests. It effectively detects early stage cervical cancer by identifying significant decreases in fluorescence linear diattenuation and polarizance, offering valuable quantitative insights into tissue changes across various pre-cancerous grades.