Significance: Longitudinal tracking of hemodynamic changes in the breast has shown potential for neoadjuvant chemotherapy (NAC) outcome prediction. Spatial frequency domain imaging (SFDI) could be suitable for frequent monitoring of shallow breast tumors, but strong sensitivity to superficial absorbers presents a challenge. Aim: We investigated the efficacy of a two-layer SFDI inverse model that accounts for varying melanin concentration in the skin to improve discrimination of optical properties of deep tissue of the breast. Approach: Hemodynamic changes in response to localized breast compression were measured in 13 healthy volunteers using a handheld SFDI device. Epidermis optical thickness was determined based on spectral fitting of the model output and used to calculate subcutaneous optical properties. Results: Optical properties from a homogeneous model yielded physiologically unreasonable absorption and scattering coefficients for highly pigmented volunteers. The two-layer model compensated for the effect of melanin and yielded properties in the expected range for healthy breast. Extracted epidermal optical thickness was higher for higher Fitzpatrick types. Compression induced a decrease in total hemoglobin consistent with tissue blanching. Conclusions: The handheld SFDI device and two-layer model show potential for imaging hemodynamic responses that potentially could help predict efficacy of NAC in patients of varying skin tones.

中文翻译：

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乳房组织受压引起的血流动力学变化的两层空间频域成像

意义：纵向追踪乳房血流动力学变化已显示出新辅助化疗（NAC）结果预测的潜力。空间频域成像（SFDI）可能适合频繁监测浅乳腺肿瘤，但对浅层吸收剂的强敏感性提出了挑战。目的：我们研究了两层SFDI逆模型的功效，该模型解释了皮肤中黑色素浓度的变化，从而提高了对乳房深层组织的光学特性的辨别力。方法：使用手持式SFDI设备在13位健康志愿者中测量了响应局部乳房压迫的血流动力学变化。表皮光学厚度是基于模型输出的光谱拟合确定的，并用于计算皮下光学特性。结果：均质模型的光学性质为色素沉着的志愿者产生了生理上不合理的吸收和散射系数。两层模型补偿了黑色素的作用，并在健康乳房的预期范围内产生了性能。对于较高的Fitzpatrick类型，提取的表皮光学厚度较高。压迫导致总血红蛋白减少，与组织变白一致。结论：手持式SFDI设备和两层模型显示了对血流动力学反应进行成像的潜力，可潜在地帮助预测NAC在不同肤色患者中的疗效。两层模型补偿了黑色素的作用，并在健康乳房的预期范围内产生了性能。对于较高的Fitzpatrick类型，提取的表皮光学厚度较高。压迫导致总血红蛋白减少，与组织变白一致。结论：手持式SFDI设备和两层模型显示了对血流动力学反应进行成像的潜力，可潜在地帮助预测NAC在不同肤色患者中的疗效。两层模型补偿了黑色素的作用，并在健康乳房的预期范围内产生了性能。对于较高的Fitzpatrick类型，提取的表皮光学厚度较高。压迫导致总血红蛋白减少，与组织变白一致。结论：手持式SFDI设备和两层模型显示了对血流动力学反应进行成像的潜力，可潜在地帮助预测NAC在不同肤色患者中的疗效。