Relaxometry

Relaxometry refers to the measurement of MR relaxation times (e.g. T1 or T2). Multiple images with different acquisition parameters are acquired and afterwards a signal model is used to estimate the relevant quantitative relaxation times.

The most accurate approaches to estimate relaxation times obtain a single readout followed by a long waiting time (i.e. long repetition time). This ensures that the data acquisition of one k-space line does not influence the signal in the following k-space line.

The following examples show how to create the sequences, simulate the data acquisition with MRzero, reconstruct the qualitative images and estimate the quantitative relaxation times using MRpro.

Available examples are:

• T1 mapping using an inversion pulse and a single line spoiled gradient echo readout

• T1 mapping using an inversion pulse and a single line spin echo readout

• T1 mapping using Modified Look-Locker Inversion recovery (MOLLI)

• T1 and T2 mapping using a spiral cardiac MR Fingerprinting sequence

• T2 mapping using a multi-echo spin echo readout

• T2* mapping using a multi-echo FLASH sequence

• T1rho mapping using a spin-lock preparation pulse and a single line spin echo readout