Three-dimensional shear-wave elastography for differentiating benign and malignant breast lesions: Comparison with two-dimensional shear-wave elastography

Objectives: To evaluate the interobserver agreement and the diagnostic performance of 3D shear-wave elastography (SWE) for breast lesions in comparison with 2D SWE. Methods: A total of 163 breast lesions (malignant 48, benign 115) in 146 women who underwent B-mode ultrasound and SWE before biopsy were included. Two radiologists reviewed six data sets (B-mode, SWE, and a combination of both for 2D and 3D ultrasound). B-mode and SWE features were recorded. BI-RADS category was assigned for B-mode and combined sets. Interobserver variability was assessed using the κ statistic. Diagnostic performance of each data set was evaluated using the area under the ROC curve (AUC). Results: SWE showed substantial to almost perfect agreement, with E _homo in 2D SWE being higher than in 3D SWE. The AUC of 2D SWE was higher than 3D SWE for all SWE features, significantly so for E_col (0.933 vs. 0.867, P = 0.002) and E_max (0.961 vs. 0.874, P = 0.006). After adding SWE to B-mode ultrasound, the AUC in 2D ultrasound increased significantly (0.968 vs. 0.912, P = 0.008), but 3D ultrasound showed no significant difference (0.966 vs. 0.935; P = 0.07). Conclusion: For 3D SWE, interobserver agreement was good, but the diagnostic performance was inferior to 2D SWE even after adding to B-mode ultrasound. Key Points: • Shear-wave elastography (SWE) provides further diagnostic information during breast ultrasound. • 3D SWE diagnostic performance is inferior to 2D SWE. • In 3D SWE, interobserver agreement was good. • 2D B-mode ultrasound showed significant diagnostic improvement when combined with 2D SWE. • 3D B-mode ultrasound performance was not significantly improved when combined with 3D SWE.