Diagnostic performance of shear-wave dispersion imaging and shear-wave elastography for differentiating benign and malignant breast masses

Objectives: Ultrasound advancements enable the automatic quantification of viscosity by measuring the dispersion slope of shear waves. This study evaluated the diagnostic performance of shear-wave dispersion imaging (SWD) in distinguishing benign from malignant breast masses and its supplementary role compared to shear-wave elastography (SWE). Materials and methods: This retrospective study included 630 pathologically confirmed breast lesions (395 benign, 235 malignant) in 604 women (mean age, 48 ± 11 years) from August 2020 to August 2021. Tumor elasticity (E_tumor) and the tumor-to-fat elasticity ratio (E_ratio) were measured using SWE, while tumor dispersion (D_tumor) and the tumor-to-fat dispersion ratio (D_ratio) were obtained using SWD. Diagnostic performance was evaluated using the AUC, with subgroup analyses based on lesion size, depth, and breast thickness. Results: D_tumor achieved the highest AUC (0.96 [95% CI: 0.95, 0.98]) compared with E_tumor (0.93 [95% CI: 0.91, 0.95]), E_ratio (0.92 [95% CI: 0.90, 0.94]), and D_ratio (0.95 [95% CI: 0.93, 0.96]) (p ≤ 0.003). D_tumor outperformed E_tumor for small lesions (≤ 10 mm and 11–20 mm: AUC 0.84 vs 0.67 and 0.91 vs 0.86, respectively; p ≤ 0.002) and BI-RADS 4B lesions (AUC 0.82 vs 0.70, p < 0.001). D_tumor maintained high performance across varying lesion depth and breast thickness, and it differentiated ductal carcinoma in situ from invasive carcinoma (p = 0.04), which SWE did not achieve. Conclusion: SWD improves the diagnostic performance across varying lesion size, depth, and breast thickness, addressing SWE’s limitations. It is particularly effective for small lesions (≤ 20 mm) and BI-RADS 4B masses. Key Points: Question To evaluate the diagnostic performance of SWD imaging, an automatic viscosity measurement derived from shear waves, in differentiating benign from malignant breast masses. Findings SWD outperformed SWE, improving diagnostic performance for small (≤ 20 mm) and BI-RADS 4B masses while maintaining consistent performance across lesion depths and breast thicknesses. Clinical relevance SWD, obtained automatically during SWE, enhances the diagnostic performance in distinguishing benign from malignant breast lesions, particularly in small and BI-RADS 4B masses, while addressing the limitations of SWE related to lesion size, depth, and breast thickness.