Synopsis

Keywords: Image acquisition: Sequences

This presentation provides an in-depth discussion of key features that make turbo/fast spin echo a robust imaging method, including configuration of the phase-encoding gradients, selection of the RF-pulse phases, effects of signal decay during the echo train, and flip angles other than 180° for the refocusing RF pulses.

The pulse sequence commonly referred to as turbo spin echo (TSE) or fast spin echo (FSE) is widely used for applications from head to toe. It is truly a “bread & butter” technique of clinical MRI. TSE/FSE pulse sequences provide a wide range of clinically-useful contrast behaviors, such as T1, T2 and proton-density weighting, fat-signal suppression (“STIR”) and fluid-signal suppression (“FLAIR”). First described in 1986 by Hennig and colleagues¹, subsequent research on optimization and refinement of this method, especially in the late 1980s and early 1990s, led to the techniques widely used in clinical practice today.

This presentation will take a “deep dive” into the TSE/FSE pulse sequence, providing an in-depth discussion of key features that make TSE/FSE a robust imaging method. The specific aspects that will be explored include: configuration of the phase-encoding gradients, selection of RF-pulse phases, impact of the signal decay/evolution during the echo train on image contrast and artifacts, and the use of flip angles other than 180° for the refocusing RF pulses, including continuously varying flip angles.

Acknowledgements

No acknowledgement found.

References

1. Hennig J, Nauerth A, Friedburg H. RARE imaging: a fast imaging method for clinical MR. Magn Reson Med. 1986; 3:823-833.