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dcemriS4 (version 0.40)

CPMG: Quantitative T2

Description

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Usage

T2.lm(signal, TE, guess, nprint=0)
## S3 method for class 'nifti':
T2.fast(cpmg, cpmg.mask, TE, verbose=FALSE)
## S3 method for class 'anlz':
T2.fast(cpmg, cpmg.mask, TE, verbose=FALSE)
## S3 method for class 'array':
T2.fast(cpmg, cpmg.mask, TE, 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 $T2$.
nprint
is an integer, that enables controlled printing of iterates if it is positive. In this case, estimates of par are printed at the beginning of the first iteration and every nprint iterations thereafter and immediately
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.
verbose
is a logical variable (default = FALSE) that allows text-based feedback during execution of the function.

Value

  • A list structure is produced with (all or some of the) parameter estimates
  • $\rho$Scaling factor between signal intensity and T2 (proton density).
  • T2T2 relaxation time.

Details

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See Also

R1.fast, R10.lm