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Impact of incidental magnetization transfer effects on inversion-recovery sequences that use a fast spin-echo readout

Simon J P Meara1, Gareth J Barker

  • 1Imaging Science and Biomedical Engineering Research Group, University of Manchester, Manchester, United Kingdom. simon.meara@manchester.ac.uk

Magnetic Resonance in Medicine
|September 28, 2007
PubMed

Insights

Magnetization transfer (MT) effects in multislice fast spin-echo (FSE) MRI alter inversion times. Increasing slices per TR decreased optimal inversion time for MT phantoms, impacting FSE-based inversion-recovery (IR) imaging.

Area of Science:

  • Magnetic Resonance Imaging (MRI)
  • Biophysical Characterization
  • Medical Physics

Background:

  • Multislice fast spin-echo (FSE) magnetic resonance (MR) imaging is susceptible to magnetization transfer (MT) effects.
  • MT effects reduce observed longitudinal relaxation times in tissues with significant bound water.
  • This phenomenon is particularly relevant for FSE-based inversion-recovery (IR) sequences, potentially altering required inversion times.

Purpose of the Study:

  • To investigate the impact of increasing slice acquisition within the repetition time (TR) on MT effects in FSE-IR sequences.
  • To determine how these effects influence the inversion time required for maximal signal suppression in specific phantoms.

Main Methods:

  • A pseudo-3D inversion-recovery fast spin-echo (IR-FSE) sequence was employed.
  • Images were acquired using a phantom composed of thermally crosslinked bovine serum albumin.
  • The number of slices acquired per TR period was systematically varied.

Main Results:

  • Increasing the number of acquired slabs per TR period resulted in a decreased inversion time for maximal signal suppression in the MT phantom.
  • This effect was not observed in a pure water phantom, highlighting the specificity to MT-susceptible tissues.
  • The findings demonstrate a clear dependence of optimal inversion time on the number of slices acquired within the TR.

Conclusions:

  • Magnetization transfer effects significantly influence FSE-based IR imaging, particularly with increased slice acceleration.
  • The optimal inversion time for MT-sensitive tissues changes with the number of slices acquired per TR.
  • These findings have critical implications for the accurate implementation and interpretation of FSE-IR sequences in clinical and research settings.

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