Balanced Gradient Echo

26 Balanced Gradient Echo

A further refinement of GRE technique involves adjusting the FID component to coincide with the spin echo component. A balanced GRE sequence (known by the acronyms trueFISP, FIESTA, and BFFE) starts out with an RF pulse of less than 90° with data sampling performed in steady state. The transverse magnetization generated induces the FID signal (1 in Fig. 26.1). The next pulse (and every pulse thereafter) not only generates transverse magnetization based on the available longitudinal magnetization but also operates as an RF refocusing pulse for the remaining transverse magnetization of the previous Fourier line measurement (2 in Fig. 26.1). The RF echoes generated by the train of excitation pulses in the steady state are then superimposed on the gradient echo. The readout gradient is prepared in such a way that the FID and the SE are sampled at the same time (3 in Fig. 26.1

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