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Fast radio-frequency enforced steady state (FRESS) spin echo MRI for quantitative T2 mapping: minimizing the apparent

Jerry S Cheung1, Enfeng Wang, XiaoAn Zhang

  • 1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.

NMR in Biomedicine
|July 15, 2011
PubMed

Insights

Accurate transverse relaxation time (T2) MRI measurements are crucial for disease diagnosis. A new fast radio-frequency enforced steady state (FRESS) spin echo (SE) sequence minimizes errors caused by short scan times, improving T2 accuracy.

Area of Science:

  • Magnetic Resonance Imaging (MRI)
  • Biomedical Engineering
  • Medical Physics

Background:

  • Transverse relaxation time (T2) is a fundamental MRI parameter vital for diagnosing various conditions like multiple sclerosis, stroke, and tumors.
  • Conventional MRI techniques often employ short repetition times (TR) to reduce scan duration, potentially introducing significant errors in T2 quantification.
  • The dependence of steady-state magnetization on echo time (TE) in standard sequences can lead to T2 underestimation if not correctly addressed.

Purpose of the Study:

  • To develop a novel MRI sequence for accurate and rapid T2 quantification.
  • To mitigate T2 measurement errors arising from short TR and TE-dependent steady-state magnetization.
  • To introduce a fast radio-frequency enforced steady state (FRESS) spin echo (SE) MRI technique.

Main Methods:

  • A fast radio-frequency enforced steady state (FRESS) spin echo (SE) MRI sequence was designed to ensure a TE-independent steady state by saturating magnetization post-echo.
  • The FRESS-SE sequence was evaluated using numerical simulations to assess its theoretical performance.
  • The sequence was implemented with an echo-planar imaging (EPI) readout for rapid data acquisition.
  • Validation was performed using both phantom studies and in vivo experiments.

Main Results:

  • Numerical simulations confirmed the TE-independent steady-state property of the FRESS-SE sequence.
  • The FRESS-SE MRI technique demonstrated the capability for fast and accurate T2 mapping.
  • Phantom and in vivo experiments validated the practical applicability and accuracy of the proposed method.

Conclusions:

  • The developed FRESS-SE T2 MRI technique offers a solution for fast and accurate T2 imaging.
  • This method effectively overcomes the limitations of conventional sequences regarding TE dependence and scan time.
  • The FRESS-SE technique is suitable for routine in vivo applications, enhancing diagnostic capabilities.

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