A method for T and T relaxation times validation and harmonization as a support to MRI mapping.

We present a proof-of-concept study focusing on a method for the intra- and inter-center validation and harmonization of data obtained from MRI T and T maps. The method is based on a set of MnCl samples that provide in-scan ground-truth reference values regardless of the details of the MRI protocol. The relaxation times of MnCl aqueous solutions were first measured by means of an NMR laboratory relaxometer, as a function of concentration and temperature. The obtained T and T values, once renormalized at the scanner temperature, were used as reference values for the MRI mapping measurements of the MnCl relaxation times. By using different clinical MRI scanners and sequences, we found a good agreement for standard and turbo sequences (limits of agreement: 5% for IR, SE, IR-TSE; 10% for TSE), while an under-estimation and an over-estimation were found respectively for MOLLI and T-prep TrueFISP, as already reported in the literature. The linearity of the relaxation rates with the concentration predicted by the Solomon-Bloembergen-Morgan theory was observed for every dataset at all temperatures, except for T-prep TrueFISP maps results. Some preliminary results of an in vivo experiment are also presented.