Mapping of relaxation parameters has found wide use in many MRI applications (cardiac, MSK, interventional, ...). While local T₁ and T₂ quantification can count on established clinical routines when performed using conventional scanners, little investigation has been carried out at different field regimes. Low to ultra-low magnetic fields, in particular, benefit of intrinsic longer T₂ and T₂*, as well as of a broader T₁ dispersion. These characteristics make parametric mapping a very attractive area of exploration.

Here at the AMT Center we are currently focusing on the development of a fast and accurate T₁ mapping sequences. Promising results have been obtained in a phantom setting  at 0.1 T and a first validation in vivo is on the way.

MR Elastography quantifies the mechanical properties of tissue, such as stiffness or viscosity. It relies on a three-step process that includes the generation of a mechanical vibration, motion capture of wave propagation using dedicated MR sequences, and data processing involving mathematical inversion problems.

Despite being a promising technique for chronic liver diseases, MRE fails when a loss of MR signal is caused by iron overload, which often occurs in fibrotic or cirrhotic organs. At low magnetic fields, MRE can become more robust and reliable thanks to the much lower magnetic susceptibility and impact from the presence of iron.

In our Center, we develop tools and methods for fast and reliable MRE at 0.1 T ranging from the vibration transducers and open-access RF coils to MR sequences and reconstruction approaches. In addition, to validate MRE techniques at any magnetic field, custom objects with controlled stiffness properties are built and synthetic data is produced from wave simulations.