Evaluation of Multiparametric Shear Wave Elastography Indices in Malignant and Benign Breast Lesions

Rationale and objectives: To evaluate the shear wave elastography indices (multiparametric SWE) of breast lesions based on patient and lesion dependent features and assess the contribution of different elastographic parameters to radiological diagnosis.

Materials and methods: Effect of patient-dependent (age and menopausal status) and lesion-dependent (distance from the areola, quadrant location, size, depth, margin and shape) factors on SWE parameters (Vmean, Vsd, Vmax, Vmin) in benign breast lesions were assessed. Only mass lesions were included in the study. Sensitivity, specificity, PPV, NPV and cut-off values for each elastography parameter was calculated.

Results: A total of 496 mass lesions of breast were evaluated. 467 of the lesions were benign and 29 were malignant. There was no significant relationship among SWE indices and age, menopausal status, lesion shape and distance to the areola in benign lesions (p>0.05). SWE indices were found to be associated with lesion margin, depth from the skin, and lesion size in benign lesions (p<0.05). All BI-RADS 3 lesions that underwent biopsy were benign (n:35); 23.5% of 4a lesions were malignant (n:4/17) and all 4b-4c-5 lesions were malignant (n:25/25). The cut-off values for malignant lesions were: Vmean 3.38 m/s, Vsd 0.81, Vmax 6.87 m/s, Vmin 1.53 m/s. All SWE parameters were statistically significant in predicting malignancy on ROC analysis, Vmax was the most sensitive (96.3%) and specific (94.7%) parameter. Cut-off values for Vmax was 6.87 m/s with an accuracy rate of 94.7%, and 3.37 m/s for Vmean and 0.8 for Vsd with 92.5% accuracy.

Conclusion: The SWE parameters to predict malignancy in breast lesions can be affected by lesion dependent features, whereas no significant effect of patient's age or menopausal status on stiffness of the lesions was observed. Vmax had the highest sensitivity for predicting malignancy.