Magnetization reset in T2-Relaxation-Under-Spin-Tagging (TRUST) MRI

Feng Xu¹, Jinsoo Uh, Hanzhang Lu¹

The T2-Relaxation-Under-Spin-Tagging (TRUST) MRI technique was developed to quantitatively estimate blood oxygenation via the measurement of pure blood R2. A limitation of the current TRUST is the long TR (=8s), as a shorter TR results in an over-estimation of R2. We applied a non-selective 90 RF pulse after the EPI acquisition, and achieved the unbiased R2 estimation in TR of 3s with the precision preserved. Furthermore, we also tested the impact of reducing the TE although previous TRUST already used a relatively short TE of 7ms. The TE of 3.6ms was found to reduce R2 estimation uncertainty by 50%.