In diffusion tensor imaging (DTI) an effective diffusion tensor in
each voxel is measured by using a set of diffusion-weighted images
(DWIs) in which diffusion gradients are applied in a multiplicity
of oblique directions. However, to estimate the diffusion tensor
accurately, one must account for the effects of all imaging and
diffusion gradient pulses on each signal echo, which are embodied
in the b matrix. For DTI to be practical clinically, one must also
acquire DWIs rapidly and free of motion artifacts, which is now
possible with diffusion-weighted echo-planar imaging (DW-EPI). An
analytical expression for the b matrix of a general DW-EPI pulse
sequence is presented and then validated experimentally by measuring
the diffusion tensor in an isotropic phantom whose diffusivity is
already known. The b matrix is written in a convenient tabular form
as a sum of individual pair-wise contributions arising from gradient
pulses applied along parallel and perpendicular directions. While
the contributions from readout and phase-encode gradient pulse trains
are predicted to have a negligible effect on the echo, the contributions
from other imaging and diffusion gradient pulses applied in both
parallel and orthogonal directions are shown to be significant in
our sequence. In general, one must understand and account for the
multiplicity of interactions between gradient pulses and the echo
signal to ensure that diffusion tensor imaging is quantitative.
%0 Journal Article
%1 Mattiello1997
%A Mattiello, J.
%A Basser, P. J.
%A Bihan, D. Le
%D 1997
%J Magnetic Resonance in Medicine
%K of Diffusion, Echo-Planar Linear Image Processing, Results, Multivariate Imaging, Motion, Computer-Assisted, Forecasting, 9001155 Analysis, Models, Phantoms, Artifacts, Reproducibility Humans, Enhancement, Algorithms,
%N 2
%P 292--300
%T The b matrix in diffusion tensor echo-planar imaging.
%V 37
%X In diffusion tensor imaging (DTI) an effective diffusion tensor in
each voxel is measured by using a set of diffusion-weighted images
(DWIs) in which diffusion gradients are applied in a multiplicity
of oblique directions. However, to estimate the diffusion tensor
accurately, one must account for the effects of all imaging and
diffusion gradient pulses on each signal echo, which are embodied
in the b matrix. For DTI to be practical clinically, one must also
acquire DWIs rapidly and free of motion artifacts, which is now
possible with diffusion-weighted echo-planar imaging (DW-EPI). An
analytical expression for the b matrix of a general DW-EPI pulse
sequence is presented and then validated experimentally by measuring
the diffusion tensor in an isotropic phantom whose diffusivity is
already known. The b matrix is written in a convenient tabular form
as a sum of individual pair-wise contributions arising from gradient
pulses applied along parallel and perpendicular directions. While
the contributions from readout and phase-encode gradient pulse trains
are predicted to have a negligible effect on the echo, the contributions
from other imaging and diffusion gradient pulses applied in both
parallel and orthogonal directions are shown to be significant in
our sequence. In general, one must understand and account for the
multiplicity of interactions between gradient pulses and the echo
signal to ensure that diffusion tensor imaging is quantitative.
@article{Mattiello1997,
abstract = {In diffusion tensor imaging (DTI) an effective diffusion tensor in
each voxel is measured by using a set of diffusion-weighted images
(DWIs) in which diffusion gradients are applied in a multiplicity
of oblique directions. However, to estimate the diffusion tensor
accurately, one must account for the effects of all imaging and
diffusion gradient pulses on each signal echo, which are embodied
in the b matrix. For DTI to be practical clinically, one must also
acquire DWIs rapidly and free of motion artifacts, which is now
possible with diffusion-weighted echo-planar imaging (DW-EPI). An
analytical expression for the b matrix of a general DW-EPI pulse
sequence is presented and then validated experimentally by measuring
the diffusion tensor in an isotropic phantom whose diffusivity is
already known. The b matrix is written in a convenient tabular form
as a sum of individual pair-wise contributions arising from gradient
pulses applied along parallel and perpendicular directions. While
the contributions from readout and phase-encode gradient pulse trains
are predicted to have a negligible effect on the echo, the contributions
from other imaging and diffusion gradient pulses applied in both
parallel and orthogonal directions are shown to be significant in
our sequence. In general, one must understand and account for the
multiplicity of interactions between gradient pulses and the echo
signal to ensure that diffusion tensor imaging is quantitative.},
added-at = {2007-01-10T11:32:01.000+0100},
author = {Mattiello, J. and Basser, P. J. and Bihan, D. Le},
biburl = {https://www.bibsonomy.org/bibtex/2f8b09fdfd760d4332909fe4d9a725d64/bmeyer},
description = {Diffusion Tensor Imaging (DTI)},
interhash = {538400bd9a2f6e07ef874176c6cee3d7},
intrahash = {f8b09fdfd760d4332909fe4d9a725d64},
journal = {Magnetic Resonance in Medicine},
keywords = {of Diffusion, Echo-Planar Linear Image Processing, Results, Multivariate Imaging, Motion, Computer-Assisted, Forecasting, 9001155 Analysis, Models, Phantoms, Artifacts, Reproducibility Humans, Enhancement, Algorithms,},
month = Feb,
number = 2,
owner = {bzfbmeye},
pages = {292--300},
pmid = {9001155},
timestamp = {2007-01-10T11:32:01.000+0100},
title = {The b matrix in diffusion tensor echo-planar imaging.},
volume = 37,
year = 1997
}