title: Interobserver variability of ultrasound elastography: how it affects the diagnosis of breast lesions.
abstract: OBJECTIVE
  The purpose of this article is to evaluate the interobserver variability of elastography on real-time ultrasound and how it influences the agreement of final assessment on ultrasound.
  
  
  METHODS
  From April to May 2009, 65 breast lesions of 53 patients (mean age, 42.6 years; range, 18-72 years) who underwent ultrasound-guided core biopsy were included in this study. Ultrasound and elastography images of the lesion subjected to biopsy were obtained and prospectively analyzed by three radiologists with individual real-time image scanning prior to biopsy. Each radiologist recorded final ultrasound BI-RADS assessments using ultrasound and combined ultrasound and elastography and the fat-to-lesion ratio and elasticity score. The histopathologic results obtained from ultrasound-guided core biopsy or excision were used as the reference standard. Diagnostic performances and interobserver agreement were analyzed.
  
  
  RESULTS
  Of the 65 lesions, 43 (66.2%) were benign, and 22 (33.8%) were malignant. Specificity (20.2-33.3%), positive predictive value (38.7-45.1%), and accuracy (46.7-55.4%) were significantly improved in combined ultrasound and elastography (p < 0.001). Area under the curve (AUC) values for all three performers did not show significant differences in ultrasound (AUC, 0.959) and combined ultrasound and elastography (AUC, 0.957) (p = 0.92). Interobserver agreement was not improved with combined ultrasound and elastography (κ = 0.25) in comparison to ultrasound only (κ = 0.37). Interobserver agreement of real-time elastography was fair in both fat-to-lesion ratio (intraclass correlation coefficient score, 0.25) and elasticity score (κ = 0.28). Moderate agreement (κ = 0.46) was seen with static elastography.
  
  
  CONCLUSIONS
  Elastography improves the specificity, positive predictive value, and accuracy of ultrasound. However, significant interobserver variability exists, with real-time elastographic performance showing fair agreement.
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seongsanno, Seodaemun-gu, Shinchondong, Seoul, Republic of Korea.
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Yoon
authors.forename: Myung Hyun
authors.initials: MH
authors.lastname: Kim
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Kim
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Moon
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kwak
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional; D016217:Ultrasonography, Mammary