title: Breast Density Estimation with Fully Automated Volumetric Method: Comparison to Radiologists' Assessment by BI-RADS Categories.
abstract: OBJECTIVE
  The objective of our study was to calculate mammographic breast density with a fully automated volumetric breast density measurement method and to compare it to breast imaging reporting and data system (BI-RADS) breast density categories assigned by two radiologists.
  
  
  METHODS
  A total of 476 full-field digital mammography examinations with standard mediolateral oblique and craniocaudal views were evaluated by two blinded radiologists and BI-RADS density categories were assigned. Using a fully automated software, mean fibroglandular tissue volume, mean breast volume, and mean volumetric breast density were calculated. Based on percentage volumetric breast density, a volumetric density grade was assigned from 1 to 4.
  
  
  RESULTS
  The weighted overall kappa was 0.895 (almost perfect agreement) for the two radiologists' BI-RADS density estimates. A statistically significant difference was seen in mean volumetric breast density among the BI-RADS density categories. With increased BI-RADS density category, increase in mean volumetric breast density was also seen (P < 0.001). A significant positive correlation was found between BI-RADS categories and volumetric density grading by fully automated software (ρ = 0.728, P < 0.001 for first radiologist and ρ = 0.725, P < 0.001 for second radiologist). Pairwise estimates of the weighted kappa between Volpara density grade and BI-RADS density category by two observers showed fair agreement (κ = 0.398 and 0.388, respectively).
  
  
  CONCLUSIONS
  In our study, a good correlation was seen between density grading using fully automated volumetric method and density grading using BI-RADS density categories assigned by the two radiologists. Thus, the fully automated volumetric method may be used to quantify breast density on routine mammography.
authors.affiliation: Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India. Electronic address: tulikardx@yahoo.com.
authors.forename: Tulika
authors.initials: T
authors.lastname: Singh
authors.affiliation: Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors.forename: Madhurima
authors.initials: M
authors.lastname: Sharma
authors.affiliation: Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors.forename: Veenu
authors.initials: V
authors.lastname: Singla
authors.affiliation: Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.
authors.forename: Niranjan
authors.initials: N
authors.lastname: Khandelwal
mesh_terms: D000328:Adult; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008327:Mammography / Q000379:methods; D008875:Middle Aged; D010808:Physical Examination; D000072177:Radiologists; D012044:Regression Analysis; D012189:Retrospective Studies; D012984:Software; D047368:Tumor Burden
keywords: Automated; BI-RADS; Breast density; Mammography; Volumetric method