Wideband SSFP: Alternating repetition time balanced steady state free precession with increased band spacing

Abstract

Balanced steady-state free precession (SSFP) imaging is limited by off-resonance banding artifacts, which occur with periodicity 1/TR in the frequency spectrum. A novel balanced SSFP technique for widening the band spacing in the frequency response is described. This method, called wideband SSFP, utilizes two alternating repetition times with alternating RF phase, and maintains high SNR and T(2)/T(1) contrast. For a fixed band spacing, this method can enable improvements in spatial resolution compared to conventional SSFP. Alternatively, for a fixed readout duration this method can widen the band spacing, and potentially avoid the banding artifacts in conventional SSFP. The method is analyzed using simulations and phantom experiments, and is applied to the reduction of banding artifacts in cine cardiac imaging and high-resolution knee imaging at 3T.