dti (version 1.4.3.1)

dwiQball-methods: Methods for Function `dwiQball' in Package `dti'

Description

The method estimates, in each voxel, the coefficients of an expansion of the apparent diffusion cefficient (ADC) with respect to a apherical harmonics orthonormal system from the DWI data contained in an object of class "dtiData".

Usage

# S4 method for dtiData
dwiQball(object, what="wODF", order=4, lambda=0, mask=NULL)

Arguments

object

Object of class "dtiData"

what

Determines quantity to estimate, coefficients ot the orientation density function (ODF) (what="ODF", what="wODF", what="aODF") or the apparent diffusion coefficient (ADC) (what="ADC") with respect to spherical harmonics of the up to the specified order.

order

even integer: maximum order of the sperical harmonics expansion

lambda

nonnegative regularization parameter.

mask

optional brain mask

Value

An object of class "dwiQball".

Methods

obj = "ANY"

Returns a warning.

obj = "dtiData"

Estimate, in each voxel, the coefficients of an expansion of the orientation density function (ODF) or the apparent diffusion coefficient (ADC) with respect to a apherical harmonics orthonormal system. Note that the maxima of the ADC have no direct interpretation as fibre orientations.

References

M. Descoteaux, E. Angelino, S. Fitzgibbons and R. Deriche, Regularized, Fast and Robust Analytical Q-Ball Imaging, Magnetic Resonance Methods, 2007, 58, 497-512.

See Also

dtiData, readDWIdata, dtiIndices-methods, medinria, '>dtiData, '>dtiTensor

Examples

# NOT RUN {
  
# }
# NOT RUN {
demo(dti_art)
# }