Quantitative Magnetization Transfer Imaging Using Balanced SSFP

In tissues, the signal of balanced steady-state free precession (bSSFP) is considerably reduced from magnetization transfer (MT). An extended bSSFP signal equation is derived, based on a binary spin-bath model including MT effects. Using this new bSSFP signal model, quantitative MT model parameters such as the fractional pool size, corresponding magnetization exchange rates, and relaxation times are estimated in human brain. The results show high correlation with the ones from standard methods, but benefit from bSSFP’s short acquisition times and high signal-to-noise ratios. This allows the acquisition of isotropic high resolution quantitative MT maps within clinically feasible acquisition times