Dynamics of 23Na during completely balanced steady-state free precession

The dynamics of 23Na during completely balanced steady-state free precession (SSFP) have been studied in numerical simulations and experiments. Results from both agree well. It is shown that during SSFP multiple quantum coherences are excited and that their excitation affects the observable signal. The signal response to the sequence parameters (flip angle, TR, and RF pulse phase cycle) shows a structure which can not be described by the Bloch equations. Due to excitation of Tˆ31(s,a), the amplitude ratio of the fast and slowly decaying components deviates from 3:2 and is a function of the sequence parameters. The results shown here represent a basis for the implementation and optimization of 23Na-SSFP imaging sequences.