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Manpage of twotenfit
twotenfit
Section: User Commands (1)
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NAME
twotenfit - Fits two diffusion tensors to diffusion MRI measurements.
SYNOPSIS
twotenfit
<data file> <scheme file> [-cylsym]
DESCRIPTION
Reads diffusion MRI data, acquired using the acquisition scheme
detailed in the scheme file, from the data file. The data file stores
the diffusion MRI data in voxel order with the measurements stored as
big-endian four-byte floats and ordered as in the scheme file. See
modelfit(1) for the format of the data file and scheme file. The
program fits a pair of diffusion tensors to each voxel and outputs the
results, in voxel order and as big-endian eight-byte doubles, to the
standard output. The program outputs seventeen values in each voxel:
[exitcode, ln(S(0)), m, a_1, D_1xx, D_1xy, D_1xz, D_1yy, D_1yz, D_1zz,
a_2, D_2xx, D_2xy, D_2xz, D_2yy, D_2yz, D_2zz]. An exit code of zero
indicates no problems. For a list of other exit codes, see
modelfit(1). The entry S(0) is an estimate of the signal at q=0; m is
the number of fitted components, which is always 2 here; a_1 is the
mixing parameter of D_1, a_2 is that for D_2.
By default, the program constrains the two diffusion tensors only to
be positive definite. The program can also constrain the diffusion
tensors to have cylindrical symmetry (two equal eigenvalues). This
program is a simple interface to the program modelfit. The modelfit
program provides more options for fitting pairs of diffusion tensors.
If the first command line argument is - the program reads data from
the standard input.
EXAMPLES
Fit two positive-definite diffusion-tensors to the data in
SubjectA.Bfloat:
twotenfit SubjectA.Bfloat A.scheme > TwoTensorA.Bdouble
Equivalently:
cat SubjectA.Bfloat | twotenfit - A.scheme > TwoTensorA.Bdouble
Fit two cylindrically symmetric positive-definite diffusion tensors:
twotenfit SubjectA.Bfloat A.scheme -cylsym > TwoTensorA.Bdouble
OPTIONS
- -cylsym
-
Constrain the diffusion tensors to have cylindrical symmetry.
AUTHORS
Daniel Alexander <camino@cs.ucl.ac.uk>
SEE ALSO
modelfit(1), dtfit(1), threetenfit(1), fa(1), trd(1), shfit(1),
shanis(1)
BUGS
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- EXAMPLES
-
- OPTIONS
-
- AUTHORS
-
- SEE ALSO
-
- BUGS
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