Evaluation of Strain and Shear Wave Ultrasound Elastography in Predicting Malignancy in BI-RADS Categories 4A and 4B Breast Lesions

Abstract

Objective: To evaluate elasticity (E) and optimal cut-off values in differentiating benign and malignant tumors in patients with breast imaging–reporting and data system (BI-RADS) 4A/4B lesions.Material and Methods: Patients aged above 18 years with BI-RADS 4A/4B lesions who had tissue biopsies November 2019 - January 2021 were enrolled. B-mode ultrasound BI-RADS classification, E/B distance ratio, and mean elasticity value in kPa and shear wave velocity (SWV) in m/s were recorded pre-biopsy.Results: A total of 148 lesions in 141 patients were included, 129 benign (87.2%), 3 high-risk (2.0%), and 16 malignant (10.8 %). Patients with breast cancer or high-risk lesions were approximately ten years older than those with benign lesions (58.9±10.5 years vs 48±10.6 years of age) (p-value<0.001). The elasticity values were significantly different between the benign and malignant groups with median E/B distance ratios 0.9 and 1.2 (p-value<0.001), median kPameans 4.2 and 7.2, and SWVmeans 1.2 m/s and 1.6 m/s, respectively. Setting SWVmean >1.28 m/s as a cut-off value showed the highest sensitivity (68.0%) among the three single elasticity values, and kPamean >7 the highest specificity (82.0%). The negative predictive value was very high, 91.0-93.0%, for all methods. When using a combined E/B ratio >1 and SWVmean >1.28 as a cut-off value, specificity increased to 93.0% with a high NPV but lower sensitivity.Conclusion: Using a combined E/B ratio >1 and SWVmean >1.28 as a cut-off value can help to differentiate between benign and malignant BI-RADS 4A and 4B lesions and avoid unnecessary biopsies.