Diffusion imaging with balanced steady state free precession

Balanced steady state free precession (bSSFP) offers high signal efficiency and relative motion insensitivity. In this study, diffusion weighted bSSFP (DW-bSSFP) was introduced by modifying standard bSSFP sequence with two pairs of balanced bipolar diffusion gradients. The diffusion effect was analyzed and described in closed forms. It was found to be coupled to the transverse and longitudinal relaxation, flip angle and spin phase advance per TR. Such coupling was demonstrated in phantom experiment at 7T. Preliminary DW-bSSFP imaging experiment was performed in rat brain in vivo for diffusion tensor imaging, yielding parametric maps qualitatively similar to those obtained with an 8-shot DW-EPI protocol. The proposed DW-bSSFP approach can provide a new means of diffusion imaging with high resolution, relative motion insensitivity and short diffusion time. Such approach may lead to improved and new diffusion characterization of neural tissues, abdominal organs, myocardium and musculoskeletal tissues.