title: Shear-wave elastographic features of breast cancers: comparison with mechanical elasticity and histopathologic characteristics.
abstract: OBJECTIVE
  The objective of this study was to compare the quantitative and qualitative shear-wave elastographic (SWE) features of breast cancers with mechanical elasticity and histopathologic characteristics.
  
  
  METHODS
  This prospective study was conducted with institutional review board approval, and written informed consent was obtained. Shear-wave elastography was performed for 30 invasive breast cancers in 30 women before surgery. The mechanical elasticity of a fresh breast tissue section, correlated with the ultrasound image, was measured using an indentation system. Quantitative (maximum, mean, minimum, and standard deviation of elasticity in kilopascals) and qualitative (color heterogeneity and presence of signal void areas in the mass) SWE features were compared with mechanical elasticity and histopathologic characteristics using the Pearson correlation coefficient and the Wilcoxon signed rank test.
  
  
  RESULTS
  Maximum SWE values showed a moderate correlation with maximum mechanical elasticity (r = 0.530, P = 0.003). There were no significant differences between SWE values and mechanical elasticity in histologic grade I or II cancers (P = 0.268). However, SWE values were significantly higher than mechanical elasticity in histologic grade III cancers (P < 0.001), which have low amounts of fibrosis, high tumor cellularity, and intratumoral necrosis. In addition, color heterogeneity was correlated with intratumoral heterogeneity of mechanical elasticity (r = 0.469, P = 0.009). Signal void areas in the masses were present in 43% of breast cancers (13 of 30) and were correlated with dense collagen depositions (n = 11) or intratumoral necrosis (n = 2).
  
  
  CONCLUSIONS
  Quantitative and qualitative SWE features reflect both the mechanical elasticity and histopathologic characteristics of breast cancers.
authors.affiliation: From the Departments of *Radiology, †Surgery, ‡Biomedical Engineering, and §Pathology, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Su Hyun
authors.initials: SH
authors.lastname: Lee
authors.forename: Woo Kyung
authors.initials: WK
authors.lastname: Moon
authors.forename: Nariya
authors.initials: N
authors.lastname: Cho
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Chang
authors.forename: Hyeong-Gon
authors.initials: HG
authors.lastname: Moon
authors.forename: Wonshik
authors.initials: W
authors.lastname: Han
authors.forename: Dong-Young
authors.initials: DY
authors.lastname: Noh
authors.forename: Jung Chan
authors.initials: JC
authors.lastname: Lee
authors.forename: Hee Chan
authors.initials: HC
authors.lastname: Kim
authors.forename: Kyoung-Bun
authors.initials: KB
authors.lastname: Lee
authors.forename: In-Ae
authors.initials: IA
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006244:Hardness; D006245:Hardness Tests / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D010173:Palpation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D033081:Shear Strength; D013314:Stress, Mechanical; D016217:Ultrasonography, Mammary / Q000379:methods*