title: Assessment of Interradiologist Agreement Regarding Mammographic Breast Density Classification Using the Fifth Edition of the BI-RADS Atlas.
abstract: OBJECTIVE
  The objective of the present study was to assess interradiologist agreement regarding mammographic breast density assessment performed using the rating scale outlined in the fifth edition of the BI-RADS atlas of the American College of Radiology.
  
  
  METHODS
  Breast density assessments of 1000 cases were conducted by five radiologists from the same institution who together had recently undergone retraining in mammographic breast density classification based on the fifth edition of BI-RADS. The readers assigned breast density grades (A-D) on the basis of the BI-RADS classification scheme. Repeat assessment of 100 cases was performed by all readers 1 month after the initial assessment. A weighted kappa was used to calculate intrareader and interreader agreement.
  
  
  RESULTS
  Intrareader agreement ranged from a kappa value of 0.86 (95% CI, 0.77-0.93) to 0.89 (95% CI, 0.81-0.95) on a four-category scale (categories A-D) and from 0.89 (95% CI, 0.86-0.92) to 0.94 (95% CI, 0.89-0.97) on a two-category scale (category A-B vs category C-D). Interreader agreement ranged from substantial (κ = 0.76; 95% CI, 0.73-0.78) to almost perfect (κ = 0.87; 95% CI, 0.86-0.89) on a four-category scale, and the overall weighted kappa value was substantial (0.79; 95% CI, 0.78-0.83). Interreader agreement on a two-category scale ranged from a kappa value of 0.85 (95% CI, 0.83-0.86) to 0.91 (95% CI, 0.90-0.92), and the overall weighted kappa was 0.88 (95% CI, 0.87-0.89).
  
  
  CONCLUSIONS
  Overall, with regard to mammographic breast density classification, radiologists had substantial interreader agreement when a four-category scale was used and almost perfect interreader agreement when a dichotomous scale was used.
authors.affiliation: 1 Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, M205, Cumberland Campus, 75 East St, Lidcombe, Sydney, NSW 2141, Australia.|2 Department of Radiography and Radiology, Faculty of Health Sciences, University of Calabar, Calabar, Nigeria.
authors.forename: Ernest U
authors.initials: EU
authors.lastname: Ekpo
authors.affiliation: 3 Faculty of Medical Sciences, Cross River University of Technology, Okuku, Nigeria.
authors.forename: Ujong Peter
authors.initials: UP
authors.lastname: Ujong
authors.affiliation: 1 Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, M205, Cumberland Campus, 75 East St, Lidcombe, Sydney, NSW 2141, Australia.
authors.forename: Claudia
authors.initials: C
authors.lastname: Mello-Thoms
authors.affiliation: 1 Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, M205, Cumberland Campus, 75 East St, Lidcombe, Sydney, NSW 2141, Australia.
authors.forename: Mark F
authors.initials: MF
authors.lastname: McEntee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000473:pathology*; D000071060:Breast Density; D001943:Breast Neoplasms / Q000145:classification / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D042361:Mammary Glands, Human / Q000002:abnormalities*; D008327:Mammography; D008875:Middle Aged; D015588:Observer Variation; D018570:Risk Assessment
keywords: BI-RADS fifth edition; breast density assessment; interreader agreement; radiologists' agreement