Quantitative T2

Description

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Usage

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T2.lm(signal, TE, guess, control=nls.lm.control())
## S4 method for signature 'array'
T2.fast(cpmg, cpmg.mask, TE, control=nls.lm.control(maxiter=150),
         multicore=FALSE, verbose=FALSE)

Arguments

signal

is the vector of signal intensities as a function of echo times.

TE

is the vector of echo times (in seconds).

guess

is the vector of initial values for the parameters of interest: rho and T2.

control

An optional list of control settings for nls.lm. See nls.lm.control for the names of the settable control values and their effect.

cpmg

is a multidimensional array of signal intensities. The last dimension is assumed to be a function of the echo times, while the previous dimenions are assued to be spatial.

cpmg.mask

is a (logical) multidimensional array that identifies the voxels to be analyzed.

multicore

is a logical variable (default = FALSE) that allows parallel processing via multicore.

verbose

is a logical variable (default = FALSE) that allows text-based feedback during execution of the function.

Details

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Value

A list structure is produced with (all or some of the) parameter estimates

rho

Scaling factor between signal intensity and T2 (proton density).

T2

T2 relaxation time.

Author(s)

Brandon Whitcher bjw34032@users.sourceforge.net

See Also

R1.fast, R10.lm

Examples

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## Example?