Breast density quantification in dual‐energy mammography using virtual anthropomorphic phantoms

Abstract

PurposeBreast density is a significant risk factor for breast cancer and can impact the sensitivity of screening mammography. Area‐based breast density measurements may not provide an accurate representation of the tissue distribution, therefore volumetric breast density (VBD) measurements are preferred. Dual‐energy mammography enables volumetric measurements without additional assumptions about breast shape. In this work we evaluated the performance of a dual‐energy decomposition technique for determining VBD by applying it to virtual anthropomorphic phantoms.MethodsThe dual‐energy decomposition formalism was used to quantify VBD on simulated dual‐energy images of anthropomorphic virtual phantoms with known tissue distributions. We simulated 150 phantoms with volumes ranging from 50 to 709 mL and VBD ranging from 15% to 60%. Using these results, we validated a correction for the presence of skin and assessed the method's intrinsic bias and variability. As a proof of concept, the method was applied to 14 sets of clinical dual‐energy images, and the resulting breast densities were compared to magnetic resonance imaging (MRI) measurements.ResultsVirtual phantom VBD measurements exhibited a strong correlation (Pearson's ) with nominal values. The proposed skin correction eliminated the variability due to breast size and reduced the bias in VBD to a constant value of −2%. Disagreement between clinical VBD measurements using MRI and dual‐energy mammography was under 10%, and the difference in the distributions was statistically non‐significant. VBD measurements in both modalities had a moderate correlation (Spearman's = 0.68).ConclusionsOur results in virtual phantoms indicate that the material decomposition method can produce accurate VBD measurements if the presence of a third material (skin) is considered. The results from our proof of concept showed agreement between MRI and dual‐energy mammography VBD. Assessment of VBD using dual‐energy images could provide complementary information in dual‐energy mammography and tomosynthesis examinations.