Shear wave elastography in the diagnosis of breast non-mass lesions: factors associated with false negative and false positive results.

ABSTRACT

OBJECTIVE: To investigate factors related to false shear wave elastography (SWE) results for breast non-mass lesions (NMLs) detected by B-mode US. METHODS: This retrospective study enrolled 152 NMLs detected by B-mode US and later pathologically confirmed (79 malignant, 73 benign). All lesions underwent B-mode US and SWE. Quantitative (mean elasticity [E mean]) and qualitative (maximum stiffness colour) SWE parameters were assessed, and 'E mean > 85.1 kPa' or 'stiff colour (green to red)' determined malignancy. Final SWE results were matched to pathology results. Multivariate logistic regression analysis identified factors associated with false SWE results for diagnosis of breast NMLs. RESULTS: Associated calcifications (E mean odds ratio [OR] = 7.60, P < 0.01; maximum stiffness colour OR = 6.30, P = 0.02), in situ cancer compared to invasive cancer (maximum stiffness colour OR = 5.29, P = 0.02), and lesion size (E mean OR = 0.90, P < 0.01; maximum stiffness colour OR = 0.91, P = 0.01) were significantly associated with false negative SWE results for malignant NMLs. Distance from the nipple (E mean OR = 0.84, P = 0.03; maximum stiffness colour OR = 0.93, P = 0.04) was significantly associated with false positive SWE results for benign NMLs. CONCLUSIONS: Presence of associated calcifications, absence of the invasive component, and smaller lesion size for malignant NMLs and shorter distance from the nipple for benign NMLs are factors significantly associated with false SWE results. KEY POINTS • Calcification and size are associated with false negative SWE in malignant NMLs. • In situ cancer is associated with false negative SWE in malignant NMLs. • Distance from the nipple is associated with false positive SWE in benign NMLs. • These factors need consideration when performing SWE on breast NMLs.