title: Observer variability of Breast Imaging Reporting and Data System (BI-RADS) for breast ultrasound.
abstract: OBJECTIVE
  To evaluate inter- and intra-observer variabilities in breast sonographic feature analysis and management, using the fourth edition of the Breast Imaging Reporting and Data System (BI-RADS).
  
  
  METHODS
  We included 136 patients with 150 breast lesions who underwent breast ultrasound (US) and ultrasound-guided core needle biopsy. A pathological diagnosis was available for all 150 lesions: 77 (51%) malignant and 73 (49%) benign. Four radiologists retrospectively reviewed sonographic images of lesions twice within an 8-week interval. The observers described each lesion, using BI-RADS descriptors and final assessment. Inter- and intra-observer variabilities were assessed with Cohen's kappa statistic. Positive predictive value and negative predictive value (NPV) for final assessment were also calculated.
  
  
  RESULTS
  For inter-observer agreements for sonographic descriptors, substantial agreement for lesion calcification and final assessment (kappa=0.61 for both), moderate agreement for lesion shape, orientation, boundary, and posterior acoustic features (kappa=0.49, 0.56, 0.59, and 0.49, respectively), and fair agreement for lesion margin and echo pattern (kappa=0.33 and 0.37, respectively) were obtained. For intra-observer agreement, substantial to perfect agreement was found for almost all lesion descriptors and final assessments. NPV for final assessment category 3 was 95%. Positive predictive value (PPV) for final assessment categorized as 4 or 5 were as follows: category 4a, 26%; category 4b, 89%; category 4c, 90%; and category 5, 97%.
  
  
  CONCLUSIONS
  Because inter- and intra-observer agreement with the BI-RADS lexicon for US is good, the use of BI-RADS lexicon can provide accurate and consistent description and assessment for breast US.
authors.affiliation: Department of Diagnostic Radiology, College of Medicine, Yonsei University, Seodaemun-ku Shinchon-dong 134, Seoul 120-752, South Korea.
authors.forename: Hye-Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Kim
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Youk
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Dae Ryong
authors.initials: DR
authors.lastname: Kang
authors.forename: Ki Keun
authors.initials: KK
authors.lastname: Oh
mesh_terms: D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D016217:Ultrasonography, Mammary