Quantitative assessment of the breast tumor stroma using cross-polarization OCT and multiphoton tomography

Breast cancer is a genetically heterogeneous disease characterized by various biomolecular and morphological features that affect the diagnosis, prognosis, and treatment response. In this study we combined cross-polarization optical coherence tomography (CP OCT) and multiphoton tomography (MPT), based on second harmonic generation (SHG), and two-photon-excited fluorescence (TPEF) to visualize tumor stroma and tumor cells in specimens of a human breast tissue. The data obtained by both techniques were compared with histopathology. The CP OCT and MPT images were quantitatively assessed to distinguish a breast normal tissue from a cancer as well as between a low and a high grade of cancer. Quantitative assessment of the CP OCT image included the calculation of signal attenuation coefficients separately for co- and cross- polarization channels and the formation the color-coded en-face distribution maps of these coefficients. The attenuation coefficient in cross- polarization channel showed better difference between breast cancer of low and high grades and distinguish them from normal tissue. The SHG images were processed using texture analysis techniques to quantify the density of collagen fibers in normal tissue and tumor. Thus, both imaging techniques have great potential to distinguish nontumorous and tumorous human breast tissue of varying degrees of malignancy and could provide identifying breast cancer margins for in surgery.