Significance: Noninvasive diffuse optical spectroscopy (DOS) is a promising adjunct diagnostic imaging technique for distinguishing benign and malignant breast lesions. Most DOS approaches require normalizing lesion biomarkers to healthy tissue since major tissue constituents exhibit large interpatient variations. However, absolute optical biomarkers are desirable as it avoids reference measurements which may be difficult or impractical to acquire. Aim: Our goal is to determine whether absolute measurements of minor absorbers such as collagen and methemoglobin (metHb) can successfully distinguish lesions. We hypothesize that metHb would exhibit less interpatient variability and be more suitable as an absolute metric for malignancy. However, we would expect collagen to exhibit more variability, because unlike metHb, collagen is also present in the healthy tissue. Approach: In this retrospective clinical study, 30 lesions with breast imaging reporting and database system score ( BIRADS ) > = 3 (12 benign and 18 malignant) measured with broadband quantitative DOS were analyzed for their oxyhemoglobin (HbO), deoxyhemoglobin (HHb), water, lipids, collagen, metHb concentrations, and optical scattering characteristics. Wilcoxon rank sum test was used to compare benign and malignant lesions for all variables in both normalized and absolute forms. Results: Among all absolute DOS parameters considered, only absolute metHb was observed to be significant for lesion discrimination (0.43 ± 0.18 μM for benign versus 0.87 ± 0.32 μM for malignant, p = 0.0002). Absolute metHb concentration was also determined to be the best predictor of malignancy with an area under the curve of 0.89. Conclusions: Our findings demonstrate that lesion metHb concentration measured by DOS can improve noninvasive optical diagnosis of breast malignancies. Since metHb concentration found in normal breast tissue is extremely low, metHb may be a more direct indicator of malignancy that does not depend on other biomarkers found in healthy tissue with significant variability. Furthermore, absolute parameters require reduced measurement time and can be utilized in cases where healthy reference tissue is not available.

中文翻译：

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绝对高铁血红蛋白浓度的宽带漫反射光谱可以区分良性和恶性乳腺病变

意义：无创漫反射光谱（DOS）是一种很有前途的辅助诊断成像技术，用于区分良性和恶性乳腺病变。大多数 DOS 方法需要将病变生物标志物标准化为健康组织，因为主要组织成分表现出较大的患者间差异。然而，绝对光学生物标志物是可取的，因为它避免了可能难以或不切实际获得的参考测量。目的：我们的目标是确定胶原蛋白和高铁血红蛋白 (metHb) 等次要吸收体的绝对测量是否可以成功区分病变。我们假设 metHb 表现出较小的患者间变异性，并且更适合作为恶性肿瘤的绝对指标。然而，我们预计胶原蛋白会表现出更多的变异性，因为与metHb不同，胶原蛋白也存在于健康组织中。方法：在这项回顾性临床研究中，分析了使用宽带定量 DOS 测量的 30 个乳腺影像报告和数据库系统评分 (BIRADS) > = 3 的病变（12 个良性和 18 个恶性）的氧合血红蛋白 (HbO)、脱氧血红蛋白 (HHb)、水、脂质、胶原蛋白、metHb 浓度和光学散射特性。Wilcoxon 秩和检验用于以标准化和绝对形式比较所有变量的良性和恶性病变。结果：在所有考虑的绝对 DOS 参数中，仅观察到绝对 metHb 对于病变区分具有显着意义（良性为 0.43 ± 0.18 μM，恶性为 0.87 ± 0.32 μM，p = 0.0002）。绝对 MeHb 浓度也被确定为恶性肿瘤的最佳预测因子，曲线下面积为 0.89。结论：我们的研究结果表明，通过 DOS 测量病灶的 metHb 浓度可以改善乳腺恶性肿瘤的无创光学诊断。由于正常乳腺组织中的metHb浓度极低，因此metHb可能是更直接的恶性肿瘤指标，不依赖于健康组织中发现的具有显着变异性的其他生物标志物。此外，绝对参数需要减少测量时间，并且可以在没有健康参考组织的情况下使用。