title: Interobserver variability of ultrasound elastography and the ultrasound BI-RADS lexicon of breast lesions.
abstract: BACKGROUND
  Elastographpy is a newly developed noninvasive imaging technique that uses ultrasound (US) to evaluate tissue stiffness. The interpretation of the same elastographic images may be variable according to reviewers. Because breast lesions are usually reported according to American College of Radiology Breast Imaging and Data System (ACR BI-RADS) lexicons and final category, we tried to compare observer variability between lexicons and final categorization of US BI-RADS and the elasticity score of US elastography.
  
  
  METHODS
  From April 2009 to February 2010, 1356 breast lesions in 1330 patients underwent ultrasound-guided core biopsy. Among them, 63 breast lesions in 55 patients (mean age, 45.7 years; range, 21-79 years) underwent both conventional ultrasound and elastography and were included in this study. Two radiologists independently performed conventional ultrasound and elastography, and another three observers reviewed conventional ultrasound images and elastography videos. Observers independently recorded the elasticity score for a 5-point scoring system proposed by Itoh et al., BI-RADS lexicons and final category using ultrasound BI-RADS. The histopathologic results were obtained and used as the reference standard. Interobserver variability was evaluated.
  
  
  RESULTS
  Of the 63 lesions, 42 (66.7 %) were benign, and 21 (33.3 %) were malignant. The highest value of concordance among all variables was achieved for the elasticity score (k = 0.59), followed by shape (k = 0.54), final category (k = 0.48), posterior acoustic features (k = 0.44), echogenecity and orientation (k = 0.43). The least concordances were margin (k = 0.26), lesion boundary (k = 0.29) and calcification (k = 0.3).
  
  
  CONCLUSIONS
  Elasticity score showed a higher level of interobserver agreement for the diagnosis of breast lesions than BI-RADS lexicons and final category.
authors.affiliation: Department of Radiology, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Dongsuro 56, Bupyeong-dong, Bupyeong-gu, Incheon, 403-720, Korea.
authors.forename: Chang Suk
authors.initials: CS
authors.lastname: Park
authors.forename: Sung Hun
authors.initials: SH
authors.lastname: Kim
authors.forename: Na Young
authors.initials: NY
authors.lastname: Jung
authors.forename: Jae Jung
authors.initials: JJ
authors.lastname: Choi
authors.forename: Bong Joo
authors.initials: BJ
authors.lastname: Kang
authors.forename: Hyun Seouk
authors.initials: HS
authors.lastname: Jung
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000473:pathology; D054459:Elasticity Imaging Techniques / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D016217:Ultrasonography, Mammary / Q000706:statistics & numerical data; D055815:Young Adult