Katja Pinker MD, Presenter: Nothing to Disclose

Stephan Gruber MD, Abstract Co-Author: Nothing to Disclose

Melanie B. Schernthaner MD, Abstract Co-Author: Nothing to Disclose

Hubert Bickel MD, Abstract Co-Author: Nothing to Disclose

Wolfgang Bogner MSC, Abstract Co-Author: Nothing to Disclose

Thomas Hans Helbich MD, Abstract Co-Author: Research Consultant, Siemens AG Research Consultant, Hologic, Inc Research Grant, Siemens AG

Andreas Burner, Abstract Co-Author: Nothing to Disclose

To compare quantitative breast density measurements with MRI using the Dixon sequence with standard qualitative ACR BIRADS categorization, and to provide a range of equivalent values for each of the two methodologies.

33 women (age range of 21-65; mean 44 years) undergoing routine screening mammography with full-field digital mammography (FFDM) were included in this prospective IRB-approved study. In all women breast density was measured with radiation- and compression- free MRI using the Dixon sequence, which aquires two datasets, one representing the fatty components and one the fibroglandular components of the breasts. The MRI breast density measurement system used a semi-automatic segmentation of the anatomic region of the breast and generated a combined histogram resulting in two discriminable clusters of fatty and fibroglandular breast tissue. The system then automatically calculated the percentage of fatty tissue (%), the percentage of fibroglandular tissue (%) and the total volume of the breast (cm3). Two breast radiologists in consensus allocated one of the four standard BIRADS density categories (1- 0-24%; 2- 25-49%, 3-50-74%, 4 >75%) to each of the 1600 mammograms. Descriptive statistics using the 25-75 % percentile were used to define the typical range of MRI density readings corresponding to the four BIRADS categories of breast density.

Density measurements ranged from 3.5% to 60% (mean 22.3%) using the computerized MRI breast density measurement. Compared with the BIRADS categories, 25-75% percentile assessment demonstrated an interquartile range of percentage breast density of 4.8-15.4% for BIRADS-1, 9.9-22% for BIRADS-2, 16.8-38.1% for BIRADS-3 and 30-51.2% for BIRADS-4.

Quantitative MRI breast density readings were consistently lower than qualitative BIRADS assessment - often by about 50 %. Equivalent values were found with computerized MRI breast density readings of 0 – 12.6%, 12.7 – 19.4%, 19.5 – 34,1% and >34.2% respectively for each of the four BIRADS categories.

As quantitative density readings may become increasingly used to assess breast cancer risk, radiologists should be aware of the significantly lower values obtained using quantitative measurement.

Pinker, K, Gruber, S, Schernthaner, M, Bickel, H, Bogner, W, Helbich, T, Burner, A, Correlation of Computerized Quantitative MR Breast Density Measurements with Standard Qualitative ACR BIRADS Classification.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11015364.html