MREdisplacement {qMRI}

Calculate the motion induced signal phase for IR-MRE in biphasic material

Description

The function takes magnitude images and phase images (as NIfTI files) recordet with inversion IT1=Inf and a second inversion time IT2 that nulls the fluid signal. Tissue parameters (Relaxation rates) are extracted from an object of class "IRmixed" calculated from data of a related IRMRI experiment.

Usage

MREdisplacement(MagnFiles1, PhaseFiles1, MagnFiles2, PhaseFiles2, TI2 = 2400,
                IRmixobj, method = c("full", "approx"),rescale=FALSE,verbose=FALSE)

Arguments

MagnFiles1

Filenames of magnitude images recorded with inversion time IT=Inf .

PhaseFiles1

Filenames of phase images recorded with inversion time IT=Inf .

MagnFiles2

Filenames of magnitude images recorded with inversion time IT=IT2.

PhaseFiles2

Filenames of phase images recorded with inversion time IT=IT2 .

TI2

Inversion time used for MagnFiles2 and PhaseFiles2. IT2 should be selected to extinguish the signal intendity for fluid.

IRmixobj

Object of class "IRmixed" obtained from a related IRMRI experiment.

method

Either "full" or "approx"

rescale

Logical, do we need to rescale phase images ?

verbose

Report scale range of phase images

Details

The first 4 arguments need to be vectors of filenames of identical length with files containing compatible 3D NIfTI images. Object IRmixobj needs to contain a components segm and Rx of compatible dimension that need to be registered to the MRE images.

Value

A list of class "IRMREbiphasic" with components

phisolid

displacement solid

phifluid

displacement fluid

Author(s)

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

References

J. Polzehl and K. Tabelow (2023), Magnetic Resonance Brain Imaging: Modeling and Data Analysis Using R, 2nd Edition, Chapter 7, Springer, Use R! Series. <doi:10.1007/978-3-031-38949-8_7>.

See Also

estimateIRfluid, estimateIRsolid, estimateIRsolidfixed,smoothIRSolid