dti (version 0.9-4)

dwiMixtensor.old-methods: Methods for Function `dwiMixtensor' in Package `dti'

Description

The method estimates, in each voxel, a mixture of radial symmetric tensors from the DWI data contained in an object of class "dtiData".

Usage

## S3 method for class 'dtiData':
dwiMixtensor.old(object, maxcomp=2, p=2, maxneighb=7, method="mixtensor", reltol=1e-8, maxit=5000)

Arguments

object

Object of class "dtiData"

maxcomp

Maximal number of mixture components.

p

Exponent in Jian-Model (only effective if method="Jian".

maxneighb

Size of neighborhood used to search for minima of the ADC. These are then used to determine initial parameters for the mixture model

method

Specifies the mixture model used. method="mixtensor" specifies a mixture of tensor models (default), method="Jian" refers to the model defined in Jian et al. (2007) with fixed p while with method="Jian2"

reltol

Relative tolerance for Rs nmmin() function.

maxit

Maximal number of iterations in Rs nmmin() function.

Value

• An object of class "dwiMixtensor".

Details

The method estimates, in each voxel, a mixture of radial symmetric tensors from the DWI data contained in an object of class "dtiData". The number of mixture components is selected depending on the data, with a maximum number of components specified by maxcomp.

If method="Jian" the model parameters from Jian et al. (2007) with fixed p are estimated. With method="Jian2" also p is estimated.

In all models tensors are restricted to be rotational sysmmetric with common excentricity and destinct largest eigenvalue.

This has been replaced by new code, see dwiMixtensor-methods.

References

Jian et al. (2007), A novel tensor distribution model for the diffusion-weighted MR signal, NeuroImage 37, 164--176.

See Also

dtiData, readDWIdata, medinria, dtiData, dwiMixtensor

Examples

demo(dti_art)