Diffusion-Weighted MRI-Based Virtual Elastography and Shear-Wave Elastography for the Assessment of Breast Lesions

Background: Diffusion-weighted imaging (DWI)-based virtual MR elastography (DWI-vMRE) in the assessment of breast lesions is still in the research stage. Purpose: To investigate the usefulness of elasticity values on DWI-vMRE in the evaluation of breast lesions, and the correlation with the values calculated from shear-wave elastography (SWE). Study Type: Prospective. Population/Subjects: 153 patients (mean age +/- standard deviation: 55 +/- 12 years) with 153 pathological confirmed breast lesions (24 benign and 129 malignant lesions). Field Strength/Sequence: 1.5-T MRI, multi-b readout segmented echo planar imaging (b-values of 0, 200, 800, and 1000 sec/mm(2)). Assessment: For DWI-vMRE assessment, lesions were manually segmented using apparent diffusion coefficient (ADC(0-1000)) map, then the region of interests were copied to the map of shifted-ADC (sADC(200-800), sADC (200-1500)). For SWE assessment, the shear modulus of the lesions was measured by US elastic modulus (mu(USE)). Intraclass/interclass kappa coefficients were calculated to measure the consistency. Statistical Tests: Pearson's correlation was used to assess the relationship between sADC and mu(USE). A receiver operating characteristic analysis with the area under the curve (AUC) was performed to compare the diagnostic accuracy between benign and malignant breast lesions of sADC and mu(USE). A P value <0.05 was considered statistically significant. Results: There were significant differences between benign and malignant breast lesions of mu(USE) (24.17 +/- 10.64 vs. 37.20 +/- 12.61), sADC(200-800) (1.38 +/- 0.31 vs. 0.97 +/- 0.18 x 10(-3) mm(2)/sec), and sADC(200-1500) (1.14 +/- 0.30 vs. 0.78 +/- 0.13 x 10(-3) mm(2)/sec). In all breast lesions, a moderate but significant correlation was observed between mu(USE) and sADC(200-800)/sADC(200-1500) (r = -0.49/-0.44). AUC values to differentiate benign from malignant lesions were as follows: mu(USE), 0.78; sADC(200-800), 0.89; sADC(200-1500), 0.89. Data Conclusions: Both SWE and DWI-vMRE could be used for the differentiation of benign versus malignant breast lesions. Furthermore, DWI-vMRE with the use of sADC show relatively higher AUC values than SWE.