Comparative study of density analysis using automated whole breast ultrasound and MRI

Purpose: The purpose of this study is to compare the measurements of breast density using three-dimensional (3-D) automated whole breast ultrasound (ABUS) and magnetic resonance imaging (MRI). Methods: In this study, 3-D ABUS and MRI breast images were obtained from 40 patients—bilaterally in 27 patients and unilaterally (due to operation in the contralateral breast) in 13 patients. To differentiate the fibroglandular and fatty tissues in ABUS and MRI images, the fuzzy C-mean classifier was used. Calculated values for percent density and breast volume from the two modalities were compared to and correlated with linear regression analysis. Intraoperator and interoperator variations among eight cases were evaluated to verify the consistency of the density analysis. Results: Mean percent density and breast volume derived from ABUS (17.63±11.87% and 418.30±132.97 cm3, respectively) and MRI images (23.79±16.62% and 544.90±207.41 cm3) demonstrated good correlation (R=0.917 and R=0.884). Intraoperator and interoperator analyses yielded slightly larger coefficients of variation for percent density and breast volume in ABUS compared to MRI. However, the differences were not statistically significant. Conclusions: ABUS and MRI showed high correlation for breast density and breast volume quantification. Both modalities could provide useful breast density information to physicians.