Fast, iterative image reconstruction for MRI in the presence of field inhomogeneities

Bradley P. Sutton, Douglas C. Noll, Jeffrey A. Fessler

Research output: Contribution to journalArticlepeer-review

Abstract

In magnetic resonance imaging, magnetic field inhomogeneities cause distortions in images that are reconstructed by conventional last Fourier transform (FFT) methods. Several noniterative image reconstruction methods are used currently to compensate for field inhomogeneities, but these methods assume that the field map that characterizes the off-resonance frequencies is spatially smooth. Recently, iterative methods have been proposed that can circumvent this assumption and provide improved compensation for off-resonance effects. However, straightforward implementations of such iterative methods suffer from inconveniently long computation times. This paper describes a tool for accelerating iterative reconstruction of field-corrected MR images: a novel time-segmented approximation to the MR signal equation. We use a min-max formulation to derive the temporal interpolator. Speedups of around 60 were achieved by combining this temporal interpolator with a nonuniform fast Fourier transform with normalized root mean squared approximation errors of 0.07%. The proposed method provides fast, accurate, field-corrected image reconstruction even when the field map is not smooth.

Original languageEnglish (US)
Pages (from-to)178-188
Number of pages11
JournalIEEE transactions on medical imaging
Volume22
Issue number2
DOIs
StatePublished - Feb 2003
Externally publishedYes

Keywords

  • Field inhomogeneity correction
  • Image reconstruction
  • Iterative methods
  • Magnetic resonance imaging
  • Temporal interpolation
  • Time segmentation

ASJC Scopus subject areas

  • Biomedical Engineering
  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology
  • Electrical and Electronic Engineering
  • Computer Science Applications
  • Computational Theory and Mathematics

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