T1 Schuff

Class: NodeT1Schuff

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Calculates a T1 map using two inversion recovery images and a reference spin or gradient echo image using Schuffs method [1]. For the method to work the repetition time must be long, i.e. \(TR >> T1\) and one inversion time must be short and one long. The short and long inversion times \(TI_1\) and \(TI_2\) must fulfill

\[ \begin{equation} TI_1 < T_1 \ln 2, ~~ TI_2 > T_1 \ln 2 \end{equation} \]

for all expected T1 values in the imaged region. Further, the echo time must be identical as well as the excitation RF-pulse. When these conditions are met T1 can be estimated using the equation [1]:

\[ \begin{equation} T_1 = \frac{TI_2-TI_1}{\ln(SE+SI_1)-\ln(SE-SI_2)}, \end{equation} \]

where \(SE\) is the signal intensity in the reference image and \(SI_1\) and \(SI_2\) are the signal intensities in the inversion recovery images with short and long inversion time, respectively.

Inputs

SE

Reference image with long repetition time.

Type: Image4DFloat, Required, Single

IR

Two inversion recovery images with short and long inversion time (and long repetition time). See above for a more precise definition of short and long inversion times.

MetaData: Requires the field InversionTime to be present in the metadata.

Type: Image4DFloat, Required, Multiple

Outputs

T1 Map

A T1 map. The T1 map has the same unit as the inversion time in the metadata, typically given in ms.

Type: Image4DFloat

References

1. Jahng, L. Stables, A. Ebel, G. B. Matson, D. J. Meyerhoff, M. W. Weiner, and N. Schuff, “Sensitive and fast T1 mapping based on two inversion recovery images and a reference image,” Med. Phys., vol. 32, no. 6, pp. 1524–1528, May 2005.

Keywords: T1 estimation, Schuff's method, T1 map