Generalized analysis of steady-state free precession in nmr imaging

Abstract

In the steady-state free precession (SSFP) with an applied linear gradient, the transverse magnetizations are periodically distributed. Fourier analysis of this periodic distribution leads to the understanding of many interesting phenomena in SSFP. It is found that there are many other higher order echoes in SSFP in addition to the previously known echoes. By deriving general description of the transverse magnetization of SSFP and by expanding the echo time independent term with Fourier series, the higher order echoes including the two previously well-known signals (FISP and CE-FAST) are analyzed. The phase evolution of each higher order echo will also be presented in the phase diagram with its magnitude. These higher order echoes are studied in detail by both computer simulations and experiments and their results are reported.