T1 IR

Class: NodeT1IR

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Calculate a T1 map using spin echo inversion recovery (IR) data. Atleast two images are required, however, more images are advised if a larger range of T1 values are expected. Inversion times, inversion flip angle (FA) and repetition time (TR) are detected automatically and it is required that the FA and TR is the same in all images. An optional mask can also be provided to limit the calculations to a region.

Produces a T1 map[ms], and S0 which is a proton and T2 weighted image. The parameter values are obtained by fitting the data to the signal equation:

\(\displaystyle S = S_0(1–(1-\cos(FA))\exp(-T_1/T_I)+\exp(-T_R/T_1))\)

Inputs

Dataset

At least two inut images with different inversion times.

Type: Image4DFloat, Required, Multiple (Minimum = 2)

Mask

A mask which defines the region in which the T1 values will be calculated.

Type: Image4DBool, Optional, Single

Outputs

T1

The T1 map.

Type: Image4DFloat

S0

The S0 map.

Type: Image4DFloat

Settings

Model Selection

For phase sensitive IR use the Real model, otherwise use the magnitude model.

Values: Real, Magnitude

References

      1. Gowland and V. L. Stevenson, “T1: the longitudinal relaxation time,” in Quantitative MRI of the brain: Measuring changes caused by disease, P. S. Tofts, Ed. Chichester: Wiley, 2003, pp. 111–41.

Keywords: T1, IR, spin, echo, inversion, recovery, longitudinal, relaxation