Analogy of Motion-Induced Phase in Diffusion-Weighted Steady-State Free Precession MRI with RF Spoiling

Rafael O'Halloran¹, Roland Bammer¹

In diffusion-weighted steady state free precession imaging combining data from multiple shots to form an image leads to artifactual signal dropout. The cause of this is random, motion-induced phase from shot to shot. A simple and intuitive way to understand this phenomenon is by analogy to RF spoiling, in which random phase is imposed on the transverse magnetization by changing the phase of the RF excitation pulse. This analogy is presented pictorially and discussed in the context of a comparison of a single-shot EPI sequence to a multi-shot SSFP sequence in a human volunteer.