Diagnostic Value of ARFI (Acoustic Radiation Force Impulse) in Differentiating Benign From Malignant Breast Lesions

Rationale and Objectives: The aim of this study was to correlate acoustic radiation force impulse (ARFI) imaging velocities with the pathology results and to evaluate the ability of ARFI in distinguishing benign from malignant breast lesions. Materials and Methods: B-mode ultrasonography (US) and ARFI were performed in patients with previously diagnosed and selected breast lesions for biopsy. Shear wave velocity (SWV) was measured inside lesions and in the surrounding parenchyma (m/s). SWV measurements as well as lesion to-parenchyma ratio (LPR) were compared between benign and malignant lesions, and receiver operating characteristic (ROC) curves were plotted. Two blinded readers independently classified the lesions as benign or malignant in two separate reading sessions, one using B-mode US alone and the other using a combined set of B-mode US and ARFI. Results: Eighty-one patients with a total of 92 breast lesions were included (57 benign and 35 malignant nodules). SWV inside lesions were significantly higher for malignant neoplasms compared to benign (medians of 9.1 m/s vs 3.5 m/s; P < 0.001). LPR was also significantly higher for malignant lesions (3.0 vs 1.4; P < 0.001). Parenchyma SWV had no differences between groups (P = 0.071). ROC curves showed a significant discriminative power for lesion SWV (area under the curve [AUC] = 0.980; P < 0.001) and LPR (AUC = 0.954; P < 0.001). For lesion measures, a cutoff of 6.593 m/s was obtained, with sensitivity and specificity of 88.6% and 96.5%, respectively. Conclusions: ARFI provides quantitative elasticity measurements, adding valuable complementary information to B-mode ultrasound, that can potentially help in breast lesion characterization and assisting the decision for biopsy recommendations.