High-resolution tensor MR elastography for breast tumour detection

MR elastography is a novel imaging technique for the visualization of elast ic properties of tissue. It is expected that this method will have diagnost ic value for the clarification of suspicious breast lesions. Low-frequency mechanical waves are coupled into the tissue and visualized via an MR seque nce which is phase-locked to the mechanical excitation. Commonly, elasticit y is assumed to be isotropic and reconstruction is performed in only two di mensions. The technique is extended to three dimensions such that the entir e symmetric elasticity tensor is assessed. This is achieved by measuring di fferent phases of the mechanical wave during one oscillatory cycle. Thereby it is possible to provide information about the anisotropy of the elastici ty tensor Finite-element simulations as well as phantom experiments are per formed to demonstrate the feasibility of the method. Initial clinical resul ts of a breast carcinoma are presented. The analysis of the eigenvalues of the elasticity tensor support the hypothesis that breast carcinoma might ex hibit an anisotropic elasticity distribution. The surrounding benign tissue appears isotropic. Thereby new and additional diagnostic information is pr ovided which might help in distinguishing between benign and malignant brea st diseases.