TY - JOUR
T1 - Fast, iterative image reconstruction for MRI in the presence of field inhomogeneities
AU - Sutton, Bradley P.
AU - Noll, Douglas C.
AU - Fessler, Jeffrey A.
N1 - Manuscript received June 14, 2002; revised October 18, 2002. This work was supported in part by a Whitaker Foundation Graduate Fellowship and in part by the UM Center for Biomedical Engineering Research. The Associate Editor responsible for coordinating the review of this paper and recommending its publication was X. Hu. Asterisk indicates corresponding author. *B. Sutton is with the Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109-2108, USA (e-mail: [email protected]).
PY - 2003/2
Y1 - 2003/2
N2 - 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.
AB - 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.
KW - Field inhomogeneity correction
KW - Image reconstruction
KW - Iterative methods
KW - Magnetic resonance imaging
KW - Temporal interpolation
KW - Time segmentation
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U2 - 10.1109/TMI.2002.808360
DO - 10.1109/TMI.2002.808360
M3 - Article
C2 - 12715994
AN - SCOPUS:0037722699
SN - 0278-0062
VL - 22
SP - 178
EP - 188
JO - IEEE transactions on medical imaging
JF - IEEE transactions on medical imaging
IS - 2
ER -