Desynchronized motion encoding in rapid steady-state free precession MR elastography
Rump J, Klatt D, Braun J, Sack I, Papazoglou S, Hamhaber U
Institute of Radiology
To accelerate in vivo MR elastography studies of highly viscous tissue we propose the use of low-frequency shear vibrations matched to the repetition time of fast SSFP sequences which include oscillating gradients for motion sensitization. In SSFP-MRE the frequency of the motion encoding gradient is desynchronized with the vibration frequency, which allows decreasing the vibration frequency without compromising the image quality due to enhanced T2*-dephasing. Despite desynchronized vibration-encoding the sensitivity of SSFP-MRE to harmonic motions is only slightly reduced compared to classical MRE. This tradeoff is overcompensated by the benefit of using low-vibration frequencies which result in high deflection amplitudes.