title: Quantification of Regional Breast Density in Four Quadrants Using 3D MRI-A Pilot Study.
abstract: OBJECTIVE
  This study presented a three-dimensional magnetic resonance (MR)-based method to separate a breast into four quadrants for quantitative measurements of the quadrant breast volume (BV) and density.
  
  
  METHODS
  Breast MR images from 58 healthy women were studied. The breast and the fibroglandular tissue were segmented by using a computer-based algorithm. A breast was divided into four quadrants using two perpendicular planes intersecting at the nipple or the nipple-centroid line. After the separation, the BV, the fibroglandular tissue volume, and the percent density (PD) were calculated. The symmetry of the quadrant BV in the left and right breasts separated by using the nipple alone, or the nipple-centroid line, was compared.
  
  
  RESULTS
  The quadrant separation made on the basis of the nipple-centroid line showed closer BVs in four quadrants than using the nipple alone. The correlation and agreement for the BV in corresponding quadrants of the left and the right breasts were improved after the nipple-centroid reorientation. Among the four quadrants, PD was the highest in the lower outer and the lowest in the upper outer (significant than the other three) quadrants (P < .05).
  
  
  CONCLUSIONS
  We presented a quantitative method to divide a breast into four quadrants. The reorientation based on the nipple-centroid line improved the left to right quadrant symmetry, and this may provide a better standardized method to measure quantitative quadrant density. The cancer occurrence rates are known to vary in different sites of a breast, and our method may provide a tool for investigating its association with the quantitative breast density.
authors: Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA.
authors: Peter T
authors: PT
authors: Fwu
authors: Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA; Department of Radiology, E-Da Hospital and I-Shou University, Kaohsiung, Taiwan.
authors: Jeon-Hor
authors: JH
authors: Chen
authors: Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA.
authors: Yifan
authors: Y
authors: Li
authors: Department of Radiology, Taichung Veterans General Hospital, Taichung, Taiwan.
authors: Siwa
authors: S
authors: Chan
authors: Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA. Electronic address: msu@uci.edu.
authors: Min-Ying
authors: MY
authors: Su