Comparative evaluation of inversion algorithms for magnetic resonance elastography

Magnetic resonance elastography (MRE) is a phase contrast based MRI imaging technique that can directly visualize and quantitatively measure propagating acoustic shear waves in tissue-like materials subjected to harmonic mechanical excitation. Full 3D complex displacement information can be acquired at MR pixel resolution throughout a 3D volume. This data allows the calculation of local quantitative values of shear modulus and the generation of images that depict tissue elasticity or stiffness. Various inversion algorithms to perform such calculations have been proposed. We discuss the assumptions underlying three such algorithms, and compare their noise sensitivity and resolution on synthetic, phantom and in vivo data sets.