Dynamic functional and mechanical response of breast tissue to compression

S A Carp,Q Fang,D A Boas,R Moore,E Rafferty,J Selb,D B Kopans

doi:10.1364/oe.16.016064

Abstract

Physiological tissue dynamics following breast compression offer new contrast mechanisms for evaluating breast health and disease with near infrared spectroscopy. We monitored the total hemoglobin concentration and hemoglobin oxygen saturation in 28 healthy female volunteers subject to repeated fractional mammographic compression. The compression induces a reduction in blood flow, in turn causing a reduction in hemoglobin oxygen saturation. At the same time, a two phase tissue viscoelastic relaxation results in a reduction and redistribution of pressure within the tissue and correspondingly modulates the tissue total hemoglobin concentration and oxygen saturation. We observed a strong correlation between the relaxing pressure and changes in the total hemoglobin concentration bearing evidence of the involvement of different vascular compartments. Consequently, we have developed a model that enables us to disentangle these effects and obtain robust estimates of the tissue oxygen consumption and blood flow. We obtain estimates of 1.9+/-1.3 micromol/100 mL/min for OC and 2.8+/-1.7 mL/100 mL/min for blood flow, consistent with other published values.

Highlights

Near infrared spectroscopy and imaging of breast cancer has seen rapid progress over the past decade as a non-invasive, low-cost method to probe the tissue physiological state through the quantification of tissue chromophores, such as oxy and deoxy-hemoglobin, water and lipids
Monitoring tissue dynamics presents a great opportunity for enriching the information content of optical measurements if a near-infrared spectroscopy (NIRS) system with sufficient time resolution is used
Breast tissue compression exposes a rich variety of dynamic features that offer additional opportunities for identifying disease markers, especially those associated with malignancies

Summary

Introduction

Near infrared spectroscopy and imaging of breast cancer has seen rapid progress over the past decade as a non-invasive, low-cost method to probe the tissue physiological state through the quantification of tissue chromophores, such as oxy and deoxy-hemoglobin, water and lipids. Made possible by technological advancement in recent years has allowed the exploration of a new dimension – time-resolved changes in tissue properties. These methods have been applied to functional brain imaging [17,18,19,20,21,22]. There is a growing trend to build optical spectroscopy systems that measure the dynamic features of breast tissue, either intrinsic [10,22] or in response to external mechanical stimulation (compression) [23,24,25]

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Conclusion