dwiQball-methods {dti}

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 signature '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.

Author(s)

Karsten Tabelow [e-mail]
J\"org Polzehl [e-mail]

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.

J. Polzehl, K. Tabelow (2019). Magnetic Resonance Brain Imaging: Modeling and Data Analysis Using R. Springer, Use R! series. Doi:10.1007/978-3-030-29184-6.

See Also

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

Examples

  ## Not run: demo(dti_art)