Turbo Spin Echo: Refinement
Andreas Markus Loening1
1Radiology, Stanford University, CA, United States

Synopsis

Keywords: Image acquisition: Sequences, Image acquisition: Fast imaging, Physics & Engineering: Pulse design

Turbo (fast) spin echo (TSE/FSE) sequences compromise the core of many imaging protocols, but their use is so routine that we rarely think about how we can get the most out of our existing sequences and how we can leverage further sequence improvements developed by MRI researchers. This lecture will focus on refining TSE/FSE parameters for clinical applications in body, MSK, and neuro imaging. Additionally, practical aspects will be discussed including radiofrequency energy deposition (SAR) limits, motion and mitigation methods, trade-offs with low refocusing flip angles, fast recovery, and moving beyond 2-D cartesian acquisitions.

Syllabus

Turbo spin echo (TSE), also known as fast spin echo (FSE), is a core sequence in magnetic resonance imaging. It often forms the bulk of MSK and neuro MR protocols, and is the predominant mechanism for acquiring T2-weighted contrast in body MR protocols.
This talk will go over many elements of refinement that can be done with TSE/FSE sequences. Topics will include:
  1. Sources of blurring (e.g. peristalsis, respiration, pulsation, T2-decay) and associated mitigation strategies (e.g. respiratory compensation, non-cartesian k-space trajectories, variable refocusing flip angle trains).
  2. Impacts of different refocusing flip angles on image contrast and susceptibility to motion
  3. Radiofrequency energy deposition (SAR) limits
  4. Fast recovery in T2-weighted imaging
  5. Single shot imaging and 3D imaging

Acknowledgements

No acknowledgement found.

References

  1. Hennig J, Weigel M, Scheffler K. Multiecho sequences with variable refocusing flip angles: optimization of signal behavior using smooth transitions between pseudo steady states (TRAPS). Magn Reson Med 2003;49:527-535.
  2. Madhuranthakam AJ, Busse RF, Brittain JH, Rofsky NM, Alsop DC. Sensitivity of low flip angle SSFSE of the abdomen to cardiac motion. In: Proceedings of the 15th Annual Meeting of ISMRM, Berlin, Germany, 2007. (abstract 2523).
  3. Litwiller DV, Holmes JH, Saranathan M, et al. Sensitivity of modulated refocusing flip angle single-shot fast spin echo to impulsive cardiac-like motion. In: Proceedings of the 22nd Annual Meeting of ISMRM, Milan, Italy, 2014. (abstract 1613).
  4. Mugler JP 3rd. Optimized three-dimensional fast-spin-echo MRI. J Magn Reson Imaging 2014;39:745-767.
  5. Busse RF, Brau A, Vu A, et al. Effects of refocusing flip angle modulation and view ordering in 3D fast spin echo. Magn Reson Med 2008;60:640-649.
  6. Busse RF, Hariharan H, Vu A, Brittain JH. Fast spin echo sequences with very long echo trains: design of variable refocusing flip angle schedules and generation of clinical T2 contrast. Magn Reson Med 2006;55:1030-1037.
  7. Mugler JP 3rd, Kiefer B, Brookeman JR. Three-dimensional T2-weighted imaging of the brain using very long spin-echo trains. In: Proceedings of the 8th Annual Meeting of ISMRM, Denver, 2000. (abstract 687).
  8. Lichy MP, Wietek BM, Mugler JP 3rd, et al. Magnetic resonance imaging of the body trunk using a single-slab, 3-dimensional, T2-weighted turbo-spin-echo sequence with high sampling efficiency (SPACE) for high spatial resolution imaging: initial clinical experiences. Invest Radiol 2005;40:754-760.
  9. Lebel RM, Wilman AH. Intuitive design guidelines for fast spin echo imaging with variable flip angle echo trains. Magn Reson Med 2007;57:972-975.
Proc. Intl. Soc. Mag. Reson. Med. 31 (2023)