Adiabatic inversion pulses for myocardial T1 mapping

Peter Kellman, Daniel A. Herzka, Michael Schacht Hansen

Research output: Contribution to journalArticle

Abstract

Purpose To evaluate the error in T1 estimates using inversion-recovery- based T1 mapping due to imperfect inversion and to perform a systematic study of adiabatic inversion pulse designs in order to maximize inversion efficiency for values of transverse relaxation (T2) in the myocardium subject to a peak power constraint. Methods The inversion factor for hyperbolic secant and tangent/hyperbolic tangent adiabatic full passage waveforms was calculated using Bloch equations. A brute-force search was conducted for design parameters: pulse duration, frequency range, shape parameters, and peak amplitude. A design was selected that maximized the inversion factor over a specified range of amplitude and off-resonance and validated using phantom measurements. Empirical correction for imperfect inversion was performed. Results The tangent/hyperbolic tangent adiabatic pulse was found to outperform hyperbolic secant designs and achieve an inversion factor of 0.96 within ±150 Hz over 25% amplitude range with 14.7 μT peak amplitude. T1 mapping errors of the selected design due to imperfect inversion was ∼4% and could be corrected to <1%. Conclusions Nonideal inversion leads to significant errors in inversion-recovery-based T1 mapping. The inversion efficiency of adiabatic pulses is sensitive to transverse relaxation. The tangent/hyperbolic tangent design achieved the best performance subject to the peak amplitude constraint.

Original languageEnglish (US)
Pages (from-to)1428-1434
Number of pages7
JournalMagnetic resonance in medicine
Volume71
Issue number4
DOIs
StatePublished - Apr 2014

Keywords

  • MOLLI
  • MRI
  • T1 mapping
  • adiabatic inversion

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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