Anisotropy of shear wave elastography in breast lesions and its correlation with histopathology

Objective To retrospectively study the anisotropy of shear wave elastography (SWE) quantitative parameters of breast lesions, and the correlation with histopathology. Methods A total of 281 consecutive women with 281 breast lesions (179 malignant, 102 benign) were included, who underwent conventional ultrasound (US) and 2D SWE before surgical excision. Three acquisitions each for transverse and longitudinal planes were obtained, and maximum elasticity (Emax), mean elasticity (Emean), standard deviation (Esd) of the whole lesion and ratio between the elasticity in the mass and the fatty tissue (Eratio) were recorded. Anisotropic difference (AD) and anisotropy factors (AF) were calculated, and correlation with histopathology was analyzed. Results The average Emax, Emean and Esd of transverse planes were significantly higher than those of longitudinal planes. AF showed positive correlation with quantitative elasticity (Emax, Emean, Esd and Eratio) (P=0.000), and was significantly higher in malignant lesions than that in benign besions (P=0.000). AUC of AF was significantly higher than that of AD (P<0.001). AF was significantly higher in invasive ductal carcinoma than that in ductal carcinoma in situ. Higher AF was associated with higher histopathological grades of invasive ductal carcinoma (P=0.000), and correlated with ER/PR(+ ). Conclusions Anisotropy of SWE is an indicator of malignancy of breast lesions, and is of predictive value for prognosis in breast cancer. Key words: Ultrasonography; Breast; Shear wave elastography; Anisotropy; Histopathology