Magnetic Resonance Elastography in Breast Cancer: A Prospective Study on Optimal Imaging Frequency Selection and Differentiation of Molecular Subtypes

BACKGROUND: MR elastography (MRE) has applications in breast cancer, but its optimal frequency and value in discriminating molecular subtypes remain unclear. PURPOSE: To identify the preferable breast MRE frequency and evaluate MRE parameters in the precision diagnosis of breast cancer. STUDY TYPE: Prospective. POPULATION: One hundred fifty-four female patients (mean age 50 ± 10.67 years) were enrolled, including five with bilateral cancer, yielding 159 lesions. FIELD STRENGTH/SEQUENCE: 3.0 T, fast gradient-echo for DCE-MRI, single-shot EPI for DWI/ADC, SE-EPI for multifrequency MRE. ASSESSMENT: The image quality of 10 frequency MRE sets was assessed (including overall image quality, diagnostic confidence, artifact impact, and signal-to-noise ratio). Stiffness (c) and viscosity (φ) were measured at the optimal frequency and compared across clinicopathological subgroups. STATISTICAL TESTS: tests. Spearman's rank correlation. Univariate and multivariate analyses. Receiver operating characteristic (ROC) curves, the area under the curve (AUC). p < 0.05 was considered statistically significant. RESULTS: The 40-70 Hz multifrequency band demonstrated significantly superior image quality compared with all other bands. Subgroup analyses showed that c and φ differed significantly between ER-positive and ER-negative groups (c values: 2.54 (2.17-2.86) vs. 2.80 (2.37-3.30) m/s; φ values: 1.17 ± 0.21 vs. 1.24 ± 0.22 radians) and across groups with different Ki-67 expression levels (c values: 2.54 ± 0.54 vs. 2.77 ± 0.57 m/s), T stage, molecular subtypes (c values: 2.55 (2.20-2.82) vs. 2.69 (2.20-2.96) vs. 2.94 (2.52-3.33) m/s), and enhancement patterns (c values: 2.34 ± 0.41 vs. 2.73 ± 0.58 m/s). Multivariable analysis identified c [OR: 5.37 (2.13-15.54)] and age group [OR: 0.27 (0.09-0.82)] as significant independent predictors of triple-negative breast cancer, and a predictive model incorporating these variables demonstrated an AUC of 0.739 in the training set and 0.700 in the validation set. DATA CONCLUSION: The 40-70 Hz multifrequency protocol may offer favorable image quality for breast MRE. MRE parameters, particularly stiffness, show potential for characterizing tissue biomechanical properties and could assist in distinguishing molecular subtypes. EVIDENCE LEVEL: 1. STAGE OF TECHNICAL EFFICACY: Stage 2.