Application of ultrasound and shear wave elastography for evaluation of non-mass-like breast cancer

Objective To discuss the ultrasound performance and elastic characteristics of non-mass-like breast cancer, and improve the ultrasound diagnosis of it． Methods Sixty-seven lesions of 63 female patients who were diagnosed as non-masslike breast lesions by operation or biopsy were examined by ultrasound and shear wave elastography (SWE) in our hospital from March 2014 to April 2015, of which 34 cases were benign lesions and 33 cases were malignant lesions． Ultrasound and shear wave elastography were performed to compare the difference between the two groups of image characteristics and elastographic features． Conventional US, SWE, and combined conventional US and SWE features were performed to analyze their diagnostic performance． Results A total of 33 non-mass-like lesions were examined, 17 lesions (51．5%) showed patchy hypoechoic area, 12 lesions (36．4%) showed patchy hypoechoic area with microcalcification, 1 lesion (3．0%) showed disorganized area, 3 lesions (9．1%) showed diffuse microcalcification, including 7 lesions (21．2%) had axillary lymph node metastasis． The maximum, mean, and minimum elasticity and elasticity ratio between lesions and surrounding parenchyma of non-mass-like breast cancer were all significantly higher than those of benign groups (P< 0．01)． In shear-wave elastography images, 39．4% (13/33) of non-mass-like breast cancer showed a localized area of color around the lesions, which presented “stiff rim sign”． The diagnostic sensitivity, specificity, positive predictive value and negative predictive value of the “stiff rim sign” were 39．4%, 91．2%, 81．3% and 60．8%, respectively． With use of combination of SWE features and conventional US, the diagnostic specificity would be improved． Conclusion SWE contributes to the diagnosis of non-mass-like of breast cancer, and the “stiff rim sign” is of certain reference value for improving the differential diagnosis．