Estimate of tissue composition in malignant and benign breast lesions by time-domain optical mammography

Abstract

The optical characterization of malignant and benign breast lesions is presented. Time-resolved transmittance measurements were performed in the 630-1060 nm range by means of a 7-wavelength optical mammograph, providing both imaging and spectroscopy information. A total of 62 lesions were analyzed, including 33 malignant and 29 benign lesions. The characterization of breast lesions was performed applying a perturbation model based on the high-order calculation of the pathlength of photons inside the lesion, which led to the assessment of oxy- and deoxy-hemoglobin, lipids, water and collagen concentrations. Significant variations between tumor and healthy tissue were observed in terms of both absorption properties and constituents concentration. In particular, benign lesions and tumors show a statistically significant discrimination in terms of absorption at several wavelengths and also in terms of oxy-hemoglobin and collagen content.

Keywords: (170.3830) Mammography; (170.5280) Photon migration; (170.6510) Spectroscopy, tissue diagnostics; (170.6920) Time-resolved imaging.

Fig. 1

(a) X-ray image (top left) and Δµ_a maps at the 7 wavelengths of the left CC view of the patient #13 with a phylloides tumor of 45 mm in the upper-outer quadrant. A reference image showing the selected lesion area is also reported (bottom left). The color-bar range (cm⁻¹) for Δµ_a maps is −0.06 to 0.25 (635 nm), −0.04 to 0.23 (685 nm), −0.02 to 0.12 (785 nm), −0.02 to 0.04 (905 nm), −0.02 to 0.02 (930 nm), −0.02 to 0.08 (975 nm), −0.02 to 0.04 (1060 nm). (b) Corresponding MTOF reference background area at the 7 wavelengths. A red arrow points to the lesion location. Compressed breast thickness 55 mm.

Fig. 2

X-ray image (top left) and ΔC_i maps of the main breast constituents (Hb, HbO₂, tHb, lipid, water and collagen) of the left CC view of the patient #13 with a phylloides tumor of 45 mm in the upper-outer quadrant. A reference image showing the selected lesion area is also reported (bottom left). A red arrow points to the lesion location. The color-bar range for ΔC_i maps is −2.9 to 8.4 (ΔHb (μM)), −12.6 to 6.6 (ΔHbO₂ (μM)), −6.2 to 6.0 (ΔtHb (μM)), - 240.4 to 77.3 (ΔLipid (mg/cm³)), −35.6 to 87.1 (ΔWater (mg/cm³)), −74.7 to 187.2 (ΔCollagen (mg/cm³)).

Fig. 3

X-ray image (top left) and Δµ_a maps at the 7 wavelengths of the left CC view of patient #99 with a 25 mm invasive ductal carcinoma in the retroareolar area. A reference image showing the selected lesion area is also reported (bottom left). A red arrow points to the lesion location. The color-bar range (cm⁻¹) for Δµ_a maps is −0.06 to 0.09 (635 nm), −0.04 to 0.06 (685 nm), −0.03 to 0.05 (785 nm), −0.06 to 0.06 (905 nm), −0.13 to 0.09 (930 nm), −0.11 to 0.22 (975 nm), −0.06 to 0.08 (1060 nm). Compressed breast thickness 46 mm.

Fig. 4

X-ray image (top left) and ΔC_i maps of the main breast constituents (Hb, HbO₂, tHb, lipid, water and collagen) of the left CC view of the patient #99 with an invasive ductal carcinoma of 25 mm in the retroareolar area. A reference image showing the selected lesion area is also reported (bottom left). A red arrow points to the lesion location. The-color bar range for ΔC_i maps is −5.2 to 7.0 (ΔHb (μM)), −12.0 to 10.1 (ΔHbO₂ (μM)), −10.5 to 12.7 (ΔtHb (μM)), −905.9 to 181.5 (ΔLipid (mg/cm³)), −164.5 to 44.8 (ΔWater (mg/cm³)), −101.2 to 261.8 (ΔCollagen (mg/cm³)).

Fig. 5

Comparison of the absorption variation Δµ_a for both malignant and benign lesions at the 7 wavelengths. For a better data visualization, the lower limit of the y-axis was rescaled to −0.5, excluding one outlier.

Fig. 6

Constituent concentration variation ∆C_i of blood parameters (a) and lipid, water and collagen (b) for malignant (red) and benign (blue) lesions.