Ultra-Low Field Quantitative T2 Mapping

We demonstrated quantitative T2 mapping at 0.064 T using a multi-echo spin-echo sequence and CALIPR subspace constrained image reconstruction. CALIPR reconstruction results had minimal evidence of undersampling, providing better artifact suppression and preservation of fine anatomical detail than compressed sensing reconstruction. Phantom validation work was performed using 14 vials doped with known concentrations of MnCl2 and showed a relationship between measured T2 and MnCl2 concentration in agreement with expectations from a mathematical model. In-vivo, we demonstrated short acquisition time (8m:40s or 5m:59s), strong agreement with a highly-sampled reference acquisition, and T2 maps with good contrast between tissue types.