title: False positive or negative results of shear-wave elastography in differentiating benign from malignant breast masses: analysis of clinical and ultrasonographic characteristics.
abstract: BACKGROUND
  Shear-wave elastography (SWE) has the potential to improve diagnostic performance of conventional ultrasound (US) in differentiating benign from malignant breast masses.
  
  
  OBJECTIVE
  To investigate false positive or negative results of SWE in differentiating benign from malignant breast masses and to analyze clinical and imaging characteristics of the masses with false SWE findings.
  
  
  METHODS
  From May to October 2013, 166 breast lesions of 164 consecutive women (mean age, 45.3 ± 10.1 years) who had been scheduled for biopsy were included. Conventional US and SWE were performed in all women before biopsy. Clinical, ultrasonographic morphologic features and SWE parameters (pattern classification and standard deviation [SD]) were recorded and compared with the histopathology results. Patient and lesion factors in the "true" and "false" groups were compared.
  
  
  RESULTS
  Of the 166 masses, 118 (71.1%) were benign and 48 (28.9%) were malignant. False SWE features were more frequently observed in benign masses. False positive rates of benign masses and false negative rates of malignancy were 53% and 8.2%, respectively, using SWE pattern analysis and were 22.4% and 10.3%, respectively, using SD values. A lesion boundary of the masses on US (P = 0.039) and younger patient age (P = 0.047) were significantly associated with false SWE findings.
  
  
  CONCLUSIONS
  These clinical and ultrasonographic features need to be carefully evaluated in performance and interpretation of SWE examinations.
authors.affiliation: Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea metalliablue@naver.com.
authors.forename: Mi Young
authors.initials: MY
authors.lastname: Kim
authors.affiliation: Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
authors.forename: Nami
authors.initials: N
authors.lastname: Choi
authors.affiliation: Department of Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Yang
authors.affiliation: Department of Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
authors.forename: Young Bum
authors.initials: YB
authors.lastname: Yoo
authors.affiliation: Department of Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
authors.forename: Kyoung Sik
authors.initials: KS
authors.lastname: Park
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D003937:Diagnosis, Differential; D054459:Elasticity Imaging Techniques; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016217:Ultrasonography, Mammary
keywords: Breast; biopsy; elastography; shear wave; ultrasound