Chimera Averaging for Robust SSFP Magnetization Transfer Contrast Imaging (MT-Chimera)

Introduction Recent studies [1] revealed that balanced SSFP shows a pronounced magnetization transfer (MT) contrast, which can be altered via the RF pulse duration and thus allows for quantitative MT imaging [2]. It is thereby assumed that changes in signal intensity are due to the MT effect alone. However, elongated RF pulses entail a prolonged TR, which may introduce signal variations due to the frequency response of balanced SSFP (banding). This obstacle may be tackled by very accurate shimming or frequency offset averaging (OA) [3]. A novel OA approach is investigated in the present study. A linear averaging method based on an SSFP with a linear frequency response [4] is employed, which provides a nearly ideal homogeneous representation irrespectively of off-resonance effects. This allows for MT SSFP imaging over a broad range of TR without stringent requirements to the shimming procedure.