Figure 2

Determination of the specific stiffness ranges for morphological constituents of the tumor. (a) Zoomed histological images for the four main morphological constituents delineated in the histological sections by an experienced histopathologist. (b, c) A detailed comparison of the stiffness maps (b) derived from OCT scans obtained in vivo at day 7 after the initiation of chemotherapy and the corresponding histological images (c), in which the black curves show the boundaries of tumor zones identified in the QuPath software (v0.1.2) by a qualified histopathologist without looking at the OCE maps (blind test). (d, e) Zoomed histology of tumor sites demonstrating high sensitivity of the OCE method in detecting small clusters of cells that are difficult to reveal during the routine histological study. (f) Total "stiffness spectrum" in which the bell-like functions correspond to averaged histograms of stiffness values determined for the main morphological constituents. For each of the four morphological constituents, 20 selected tumor zones similar to the representative histological fragments in panel (a) were examined. (g) The graph showing the boundaries of the stiffness ranges and the color palette used for segmentation of the OCE-based stiffness maps shown in (b). (h) Segmented OCE images derived from the stiffness maps (b) using the color palette and the characteristic stiffness ranges shown in (g). Scale bar for all images = 100 μm.