Optical scattering coefficient estimated by optical coherence tomography correlates with collagen content in ovarian tissue

Abstract

Optical scattering coefficient from ex vivo unfixed normal and malignant ovarian tissue was quantitatively extracted by fitting optical coherence tomography (OCT) A-line signals to a single scattering model. 1097 average A-line measurements at a wavelength of 1310 nm were performed at 108 sites obtained from 18 ovaries. The average scattering coefficient obtained from the normal tissue group consisted of 833 measurements from 88 sites was 2.41 mm(-1) (± 0.59), while the average coefficient obtained from the malignant tissue group consisted of 264 measurements from 20 sites was 1.55 mm(-1) (± 0.46). The malignant ovarian tissue showed significant lower scattering than the normal group (p < 0.001). The amount of collagen within OCT imaging depth was analyzed from the tissue histological section stained with Sirius Red. The average collagen area fraction (CAF) obtained from the normal tissue group was 48.4% (± 12.3%), while the average CAF obtained from the malignant tissue group was 11.4% (± 4.7%). A statistical significance of the collagen content was found between the two groups (p < 0.001). These results demonstrated that quantitative measurements of optical scattering coefficient from OCT images could be a potential powerful method for ovarian cancer detection.

Figure 1

One set of examples from normal [(a), (b), and (c)] and malignant [(d), (e), and (f)] ovarian tissue. (a) and (d) OCT images, (b) and (e) H&Es, and (c) and (f) SR stains. Inset: fitting example; blue arrows: collagen bundles.

Figure 2

(a) Histograms of μ_s obtained from normal (n = 833) and malignant (n = 264) ovarian tissue groups, Gaussian distribution fits are also shown. (b) Statistics of normal (mean ± std: 2.41 ± 0.59) and malignant groups (mean ± std: 1.55 ± 0.46). (c) ROC curve of μ_s. Inset table: specificity and sensitivity at different thresholds.

Figure 3

(a) Histograms of CAFs obtained from normal (n = 158) and malignant (n = 143) ovarian tissue groups, Gaussian distribution fits are shown. (b) Statistics of normal (mean ± std: 48.8 ± 12.3) and malignant groups (mean ± std: 11.4 ± 4.7). (c) ROC curve of CAF, Inset table: specificity and sensitivity at different thresholds.