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T1
Relaxation tab
To display the T1
Relaxation tab, select Data modelling ... from the Processing
menu of the ROI intensity curves dialog.
Curve fitting Sequence type: Inversion Recovery (IR): input data is IR sequence with multiple (2 or more) inversion times
(Tis) of the form: S(TI)= So[1-2 exp(-TI/T1)]. The input data can either be
of type Modulus in which case only positive values are present in the
input data and the Modulus curve option should be chosen. If input
data is of type Real in which case both positive and negative values
are present in the input data, then the Real curve option should be
selected. NOTE: Axis Option must be set to <Inversion time> for
this option to be active. Baseline offset: The model includes an offset term to account for the fact that
values are never zero (due to a noise floor) in the raw data. Only enabled
when Modulus curve is selected. Look-Locker correction: Corrects for the effect of multiple (low flip angle) excitations
on the resulting IR curve shape. This is a special option typically applied
to IR data acquired with the Lock-Locker type sequence (mostly on Philips
scanners) Correct for imperfect inversion pulses: The inversion pulse is included as a model
parameter so that the equation fitted to the data becomes: S(TI)= So[1-K.exp(-TI/T1)],
where K =2 for perfect inversion (180 degree) pulse. Saturation Recovery (SR): Input data is a SR sequence with two or more delay times (TDs) of
the form S(TD)=So[1-exp(TD/T1)] Correct for imperfect inversion pulses: The saturation pulse is included as a model
parameter so that the equation fitted to the data becomes: S(TI)= So[1-K.exp(-TI/T1)],
where K =1 for perfect saturation (90 degree) pulse. Multi-flip angle: Input data is a spoiled gradient echo (SPGR) type sequence with
two or more flip angles. Here, the repetition time for the sequence must be
specified. NOTE: Axis Option must be set to <flip angle> for
this option to be active. Related topics:
T2
Relaxation tab
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