Breast Ultrasound Elastography and Magnetic Resonance Imaging of Fibrotic Changes of Breast Disease: Correlations Between Elastography Findings and Pathologic and Short Tau Inversion Recovery Imaging Results, Including the Enhancement Ratio and Apparent Diffusion Coefficient

Purpose: Ultrasound (US) elastography provides information regarding tissue hardness and is expected to become a novel diagnostic tool for breast disease. In contrast, magnetic resonance (MR) images reflect the tissue characteristics. Fibrosis of the stroma of breast diseases may affect their hardness. We investigated the correlation among elasticity score (ES) and signal intensity of short Tau inversion recovery MR images, enhancement ratio, apparent diffusion coefficient (ADC), and the fibrosis in the breast lesions. Materials and Methods: We reviewed the findings of US elastography and MR imaging from 41 consecutive patients with breast lesions (25 invasive ductal carcinoma, 3 fibroadenoma, 1 phyllodes tumor, 2 ductal hyperplasia, 2 primary malignant lymphoma, 3 mastopathy, 1 metastasis, 1 tubular adenoma, 1 ductal carcinoma in situ, 1 diabetic mastopathy, and 1 intraductal papilloma). In each patient, elastography images were classified based on Tsukuba ES. We calculated the ratio of signal intensity of the lesion to the muscle on short Tau inversion recovery images (L/M ratio), enhancement ratio of early to precontrast and early to delayed images, and ADC for each lesion. The ES and MR findings were correlated with the degree of fibrosis (based on Masson trichrome stain). Results: The ES significantly correlated with the L/M ratio (P = 0.0306) and the ADC (P = 0.0256). The stromal fibrosis also correlated with ES (P = 0.0023), the L/M ratio (P = 0.0344), and enhancement ratio of the early-to-delayed images (P = 0.049). Conclusions: The ES and L/M ratio are correlated significantly with each other, and they are correlated with the fibrosis. These results suggest that they will provide the information on the fibrosis and may help the diagnosis of breast lesions.