title: BI-RADS Density Classification From Areometric and Volumetric Automatic Breast Density Measurements.
abstract: OBJECTIVE
  The aim of our study was to classify breast density using areometric and volumetric automatic measurements to best match Breast Imaging-Reporting and Data System (BI-RADS) density scores, and determine which technique best agrees with BI-RADS. Second, this study aimed to provide a set of threshold values for areometric and volumetric density to estimate BI-RADS categories.
  
  
  METHODS
  We randomly selected 537 full-field digital mammography examinations from a population-based screening program. Five radiologists assessed breast density using BI-RADS with all views available. A commercial program calculated areometric and volumetric breast density automatically. We compared automatically calculated density to all BI-RADS density thresholds using area under the receiver operating characteristic curve, and used Youden's index to estimate thresholds in automatic densities, with matching sensitivity and specificity. The 95% confidence intervals were estimated by bootstrapping.
  
  
  RESULTS
  Areometric density correlated well with volumetric density (r(2) = 0.76, excluding outliers, n = 2). For the BI-RADS threshold between II and III, areometric and volumetric assessment showed about equal area under the curve (0.94 vs. 0.93). For the threshold between I and II, areometric assessment was better than volumetric assessment (0.91 vs. 0.86). For the threshold between III and IV, volumetric assessment was better than areometric assessment (0.97 vs. 0.92).
  
  
  CONCLUSIONS
  Volumetric assessment is equal to or better than areometric assessment for the most clinically relevant thresholds (ie, between scattered fibroglandular and heterogeneously dense, and between heterogeneously dense and extremely dense breasts). Thresholds found in this study can be applied in daily practice to automatic measurements of density to estimate BI-RADS classification.
authors: The Intervention Centre, Rikshospitalet, Postbox 4950, Nydalen, 0424 Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Postbox 1171, Blindern, 1318, Oslo, Norway. Electronic address: Bjorn.Helge.Osteras@ous-hf.no.
authors: Bjørn Helge
authors: BH
authors: Østerås
authors: The Intervention Centre, Rikshospitalet, Postbox 4950, Nydalen, 0424 Oslo, Norway; Institute of Physics, University of Oslo, Oslo, Norway.
authors: Anne Catrine T
authors: AC
authors: Martinsen
authors: Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
authors: Siri Helene B
authors: SH
authors: Brandal
authors: Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
authors: Khalida Nasreen
authors: KN
authors: Chaudhry
authors: Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
authors: Ellen
authors: E
authors: Eben
authors: Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
authors: Unni
authors: U
authors: Haakenaasen
authors: Oslo Centre for Biostatistics and Epidemiology, Oslo University Hospital, Oslo, Norway.
authors: Ragnhild Sørum
authors: RS
authors: Falk
authors: Institute of Clinical Medicine, University of Oslo, Postbox 1171, Blindern, 1318, Oslo, Norway; Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
authors: Per
authors: P
authors: Skaane
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008327:Mammography / Q000379:methods* / Q000706:statistics & numerical data; D008875:Middle Aged; D012372:ROC Curve; D011873:Radiology Information Systems / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software
keywords: Automated breast density; BI-RADS density; FFDM; personalized screening