Passive Array Mechanical Driver for Magnetic Resonance Elastography of the Breast

V. Khozikov, P. J. Rossman, R. L. Ehman Radiology, Mayo Clinic and Foundation, Rochester, MN, United States Introduction. Dynamic magnetic resonance elastography (MRE) is a method for quantitatively imaging the mechanical properties of tissue, using modified phasecontrast MRI to visualize applied shear waves [1]. There is interest in exploring possible applications of MRE in the diagnosis of breast cancer, where the technique might be used as an adjunct to contrast-enhanced MRI. Several groups are currently working to develop implementations that will have sufficient reliability to allow clinical trials to be conducted to test the capacity of MRE to aid the characterization of enhancing breast lesions [2, 3]. These efforts have focused on developing optimized pulse sequences for rapidly and sensitively imaging the applied shear waves, and developing mathematical inversion techniques to reliably compute the local mechanical properties of tissue from the wave images. A third challenge is to develop suitable methods of applying mechanical waves during breast MRI. The approach to date has been to design a special breast MRI coil that also contains mechanical drivers [4]. The disadvantage of this approach is that the imaging performance of the special-purpose combined device may be inferior to the latest commercial multichannel breast MRI coils. This creates difficulties in accruing patients to a trial of MRE-assisted breast MRI, because the contrast-enhanced breast images obtained with the combined device may be inferior to what can be obtained with a state-of-the-art breast RF coil system. An approach that could eliminate this problem would be to develop a mechanical driver device that can be used in combination with any standard breast RF coil system. In this report, we describe our progress towards that goal.