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Fa

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fa

Section: User Commands (1)
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NAME

fa - Computes the fractional anisotropy of tensors.

 

SYNOPSIS

fa [-inputmodel <dt|twotensor|threetensor|multitensor>]

 

DESCRIPTION

Reads diffusion tensor (single, two-tensor or three-tensor) data from the standard input, computes the fractional anisotropy (FA) of each tensor and outputs the results to the standard output. For multiple-tensor data the program outputs the FA of each tensor, so for three-tensor data, for example, the output contains three fractional anisotropy values per voxel.

 

EXAMPLES

Compute the FA in each voxel of diffusion MRI data set SubjectA.Bfloat and store the output in FA_A.Bdouble:

dtfit SubjectA.Bfloat test/A.scheme | fa > FA_A.Bdouble

Compute the FA for each component of the two-tensor fit to the same data set:

twotenfit SubjectA.Bfloat test/A.scheme | fa -inputmodel twotensor > FA_A.Bdouble

Compute the FA for 10000 independent trials of fitting the diffusion tensor to data synthesized from test function 1 (see datasynth(1)) using imaging scheme A.scheme and assuming signal to noise ratio of 16 at b=0:

datasynth -testfunc 1 -voxels 10000 -snr 16 -schemefile A.scheme | dtfit - A.scheme | fa > FA_A_SNR16.Bdouble

 

OPTIONS

-inputmodel <model type>

Specifies the model that the input data contains parameters for. Possible model types are: "dt" (diffusion-tensor data), "twotensor" (two-tensor data), "threetensor" (three-tensor data), and "multitensor" (see multitenfit(1)). By default, the program assumes that the input data contains a single diffusion tensor in each voxel.

-inputdatatype <data type of input>

Specifies the data type of the input file. The data type can be any of the following strings: "char", "short", "int", "long", "float" or "double". See camino(1).

-outputdatatype <data type of output>

Specifies the data type of the output data. The data type can be any of the following strings: "char", "short", "int", "long", "float" or "double". See camino(1).

 

AUTHORS

Daniel Alexander <camino@cs.ucl.ac.uk>

 

SEE ALSO

trd(1), md(1), dtpds(1), dtfit(1), twotenfit(1), threetenfit(1), modelfit(1).

 

BUGS

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Index

NAME

SYNOPSIS

DESCRIPTION

EXAMPLES

OPTIONS

AUTHORS

SEE ALSO

BUGS

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Time: 02:07:11 GMT, December 04, 2017