A MRI gradient waveform model for automated sequence calibration

B. R. Barker, B. T. Archer, W. A. Erdman, Ronald M Peshock

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

In order to set up magnetic resonance imaging (MRI) procedures of arbitrary voxel dimensions, slice orientation, and sequence timing in a reasonable time, some form of automatic gradient pulse calibration is required. One such method, involving simulation of gradient waveforms, is presented. Waveforms are modeled based on measurements of the step response. The model used divides each transition into three time regions: a “start” region in the first 0.3 ms, a “slew” region, and a “tail” region representing decay of the eddy current compensation error. In the “slew” region, the time derivative of the gradient, G’(t) is expressed as a function of G(t). The first two regions are nonlinear with respect to demand. The mean error in the simulated gradient is generally less than 0.04 mT m_1 in spin echo sequences. Image signal/noise ratios resulting from sequences calibrated using the model are within 5% of those of empirically calibrated sequences.

Original languageEnglish (US)
Pages (from-to)1483-1489
Number of pages7
JournalMedical physics
Volume19
Issue number6
DOIs
StatePublished - Nov 1992

Keywords

  • calibration
  • computer simulation
  • gradient
  • gradient switching
  • magnetic resonance imaging (MRI)

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

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