title: Simple rules for ultrasonographic subcategorization of BI-RADS®-US 4 breast masses.
abstract: OBJECTIVE
  To evaluate an objective method for ultrasonographic (US) subcategorization of BI-RADS(®)-US 4 breast masses based on clear and simple rules in order for woman to benefit from a more complete and homogeneous breast mass analysis.
  
  
  METHODS
  In this cross-sectional study, we selected 330 women, with 339 US breast masses, classified as BI-RADS(®)-US 4. Three physicians experienced in breast imaging independently reviewed all US images, assessing mass shape, margins, orientation, echo texture and vascularity. These experts further subdivided the masses into subcategories 4a, 4b and 4c, according to simple US rules. Inter-observer agreement was calculated for US features categories and for final subcategory assessment. We also estimated the positive predictive value (PPV) for BI-RADS(®)-US subcategories 4a, 4b and 4c assigned by each of the three observers.
  
  
  RESULTS
  Pathological examination of all masses confirmed 144 (42%) malignant and 195 (58%) benign tumors. Moderate agreement was obtained for mass shape, margins, vascularity and for final BI-RADS(®)-US 4 subcategory. Substantial agreement was obtained for the description of mass orientation and echo texture. The PPV for subcategories 4a, 4b and 4c were, 17%, 45% and 85%, respectively, for the first observer and 20%, 38% and 79% and 17%, 40% and 85% for the other two observers.
  
  
  CONCLUSIONS
  Standardization of a US subcategorization of BI-RADS(®)-US 4 breast masses seems to be feasible, with substantial inter-observer agreement and progressive increase in the PPV in the subcategories 4a, 4b and 4c, provided that clear and simple classification rules are defined.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medical Sciences, State University of Campinas - Unicamp, Campinas, São Paulo, Brazil. rodrigoj@hotmail.com
authors.forename: Rodrigo Menezes
authors.initials: RM
authors.lastname: Jales
authors.forename: Luís Otavio
authors.initials: LO
authors.lastname: Sarian
authors.forename: Renato
authors.initials: R
authors.lastname: Torresan
authors.forename: Emílio Francisco
authors.initials: EF
authors.lastname: Marussi
authors.forename: Beatriz Regina
authors.initials: BR
authors.lastname: Alvares
authors.forename: Sophie
authors.initials: S
authors.lastname: Derchain
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001938:Brazil / Q000453:epidemiology; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods* / Q000706:statistics & numerical data*; D055815:Young Adult