Local versus Whole Breast Volumetric Breast Density Assessments and Implications

• Published in: Breast Imaging pp. 775 - 782
• Main Authors: Ren, Baorui, Smith, Andrew P., Jing, Zhenxue
• Format: Book Chapter
• Language: English
• Published: Berlin, Heidelberg Springer Berlin Heidelberg
• Series: Lecture Notes in Computer Science
• Subjects: 50/50 model; AEC; automatic exposure control; local breast density; volumetric breast density
• DOI: 10.1007/978-3-642-31271-7_100
• ISBN: 9783642312700; 3642312705
• ISSN: 0302-9743

Mammographic breast density is very important in the area of cancer risk evaluation, dosimetry and image quality optimization. Many studies have shown that a breast consisting of 50% glandular and 50% adipose tissues is not a representative model of typical breast composition, as the mean volumetric breast density has been found to be less than 20%, much lower than the commonly assumed value of 50/50. In this paper we investigate the characteristics of local breast density distribution of a breast in a large population. We find that the maximum local breast density, calculated from a densest region of a breast, is about 2.3X as high as the mean whole breast density. Therefore the maximum local breast density seems to match the 50/50 model better. Since modern mammography systems employ automatic exposure control (AEC) to ensure acceptable image quality for dense regions of a breast, and since the local breast density over AEC sensor regions often fall into the range of 40% and higher, the 50/50 breast model and physical phantoms should continue to be used in development of x-ray technique and clinical evaluation of mammography systems.