A motion correction scheme by twin-echo navigation for diffusion-weighted magnetic resonance imaging with multiple RF echo acquisition

In this paper, a series of diffusion-weighted fast spin-echo (FSE) sequences with a new motion correction scheme are introduced. This correction scheme is based on the navigator echo technique. Unlike conventional spin-echo imaging, motion correction for FSE is complicated by the phase oscillation between odd-numbered and even-numbered echoes and the complex phase relationship between spin echo and stimulated echo components. In our approach, incoherent phase shifting due to motion is monitored by consecutive acquisition of two navigator echoes, which provide information on both inter-echo and intra-echo train phase shifts. Applications to both phantom and in vivo studies are presented.