Utilizing MR Elastography to Visualize Higher Harmonic Components of Wave Propagation in Phantoms with Interfaces

While MRE can be used to calculate mechanical properties of tissue, bio-interfaces can cause distortions in the shear-wave propagation patterns which are difficult to account for with current MRE techniques. Therefore, we utilized three specialized MRE sequences to visualize the first three harmonics of wave propagation in phantoms with simulated bio-interfaces. We were able to measure the doubling and tripling of wave number in the phantoms excited at the fundamental vibration frequency using this optimized MRE protocol. We characterized differences in wave propagation at higher harmonics along phantom interfaces, and observed substantial differences in wave characteristics based on adhesion level.