Minor tissue absorbers can distinguish benign and malignant breast lesions using broadband quantitative diffuse optical spectroscopy

Abstract

Noninvasive diffuse optical spectroscopy (DOS) is promising as an adjunct diagnostic imaging technique for distinguishing benign and malignant breast lesions. However, most DOS approaches require normalizing lesion optical biomarkers to healthy values in reference tissue since major tissue constituents exhibit large inter-patient variations. Our goal is to determine whether absolute measurements of minor optical absorbers such as collagen and methemoglobin (metHb) can successfully distinguish benign and malignant breast lesions. In this retrospective clinical study, 30 lesions with BIRADS score >= 3 (12 benign and 18 malignant lesions from 28 subjects) measured with broadband quantitative DOS were analyzed for their oxy-, deoxy- hemoglobin, water, lipids, collagen, and metHb concentrations as well as their optical scattering characteristics. Amongst all absolute DOS parameters (i.e., without normalization to healthy tissue) considered, only absolute metHb was observed to be significant for lesion discrimination (0.43±0.18 μM for benign vs 0.87±0.32 μM for malignant, p = 0.0002). Our findings demonstrate that lesion metHb concentration measured by quantitative DOS can improve noninvasive optical diagnosis of breast malignancies.