Shear-wave elastography in evaluation of Non-mass breast lesions, does it perform equally well in palpable and non-palpable non-mass lesions

Purpose: We correlated B-mode and SWE images of non-mass lesions (NML) to assess the role of SWE in evaluation of NML detected in ultrasound. Methods and Materials: B-mode and SWE images were correlated with pathological results. Qualitative and quantitative tissue elasticity were displayed with color-coded map and color scale ranging from0kPa(dark blue; soft)to180kPa(red; stiff).Quantitative elasticity values were measured by drawing a Q box over the stiffest portion and another Q box on adjacent normal breast tissue. The maximum stiffness color scale was measured. Pathologically the NML were categorized into4groups of low risk benign, high risk benign, DCIS and invasive carcinoma. Morphologically NML were categorized into four categories of NM ductal, NM non-ductal, tissue distortion and shadowing. Descriptive statistics were given for each category. Maximum and mean stiffness, were compared between the benign and malignant pathologies. Results: Out of 567US guided CNB’s, 84 patients had NML including58 non-high risk benign lesions, 7high risk benign lesions, 7DCIS and 12invasive carcinomas. There were47non-palpable lesions included 38benign lesions including4high risk and34 non-high risk lesions, 5DCIS and4 invasive carcinomas. Palpable lesions included27benign lesions including3high risk and24non-high risk, 2DCIS and8invasive lesions. Within the non-palpable NML, there were24lesions with ductal pattern, 20with non-ductal pattern, 4lesions with tissue distortion and4lesions only had shadowing. Among the palpable NML, there were11lesions with ductal pattern, 24lesions with non-ductal pattern, and3with some calcification, 6lesions with tissue distortion and3lesions with shadowing. The mean, max and ratio were different between the four groups in palpable as well as non-palpable NML. (P=0.002, 0.005and0.038) (P=0.008, 0.006and0.35). Conclusion: SWE might help to categorize lesions not only in benign or malignant but also high versus low risk. The value is maintained whether the NML is palpable or not.