Mammographic density estimation: one-to-one comparison of digital mammography and digital breast tomosynthesis using fully automated software.

To compare breast density on digital mammography and digital breast tomosynthesis using fully automated software.Following institutional approval and written informed consent from all participating women, both digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) were obtained. Breast percentage density was calculated with software on DBT and FFDM.Fifty consecutive patients (mean age, 51 years; range, 35-83 years) underwent both FFDM and DBT. Using a method based on the integral curve, breast density showed higher results on FFDM (68.1 \ub1 12.1 for FFDM and 51.9 \ub1 6.5 for DBT). FFDM overestimated breast density in 16.2\% (P < 0.0001). Using a method based on maximum entropy thresholding, breast density showed higher results on FFDM (68.1 \ub1 12.1 for FFDM and 51.9 \ub1 6.5 for DBT). FFDM overestimated breast density in 11.4\% (P < 0.0001). There was a good correlation among BI-RADS categories on a four-grade scale and the density evaluated with DBT and FFDM (r = 0.54, P < 0.01 and r = 0.44, P < 0.01).Breast density appeared to be significantly underestimated on digital breast tomosynthesis.Breast density is considered to be an independent risk factor for cancer Density can be assessed on full-field digital mammography and digital breast tomosynthesis Objective automated estimation of breast density eliminates subjectivity Automated estimation is more accurate than BI-RADS quantitative evaluation Breast density may be significantly underestimated on digital breast tomosynthesis