Quadrature Motion Encoding (QuME): A Novel Motion Encoding Scheme for MR Elastography

We propose a novel approach to motion encoding for spin-echo-based MR elastography called quadrature motion encoding (QuME) in which the second motion-encoding gradient (MEG) after the refocusing pulse is used to measure the quadrature component of the in vivo harmonic motion induced by an external mechanical vibration. Unlike the conventional encoding method that shifts the temporal relation between the motion and MEGs, QuME alters the amplitudes of MEGs from one time step to the next. This concept was implemented on a 3T GE scanner and demonstrated the ability to shorten the echo time of SLIM-MRE for human brain MRE.