T1 and T2 measurement variability across commercial and prototype 0.55T systems

We compare T1 and T2 measurements between the Free. Max and ramped-down Aera using the ISMRM/NIST system phantom at multiple sites. All 0.55T systems had comparable, to each other, measurements of T1 and T2 on both the NiCl2 and MnCl2 arrays. The T1 measurement of the NiCl2 array by VFA-GRE with B1+correction was overestimated compared to the site-reference by 1% to 92%. The rest of the measurements – MnCl2 T1, NiCl2 T2, and MnCl2 T2 – were within +/-20% of the site-reference and NMR-reference values. As adoption of 0.55T platforms increases, it is important to characterize and compare systems across sites.