Simultaneous B 1 1 and T 1 1 mapping using spiral multislice variable flip angle acquisitions for whole‐brain coverage in less than one minute

摘要

Purpose Variable flip angle (VFA)‐based T 1 quantification techniques are highly sensitive to B 1 inhomogeneities and to residual T 2 dependency arising from incomplete spoiling. Here, a rapid spiral VFA acquisition scheme with high spoiling efficiency is proposed for simultaneous whole‐brain B 1 and T 1 mapping. Methods VFA acquisitions at 2 different flip angles are performed to quantify T 1 using a steady‐state prepared spiral 2D multislice spoiled gradient‐echo sequence with the acquisition of 10 and 20 spiral interleaves at 1.5T and 3T, respectively. Additionally, parallel imaging acceleration of factor 2 is investigated at 3T. The free induction decay induced by the preparation pulse is sampled by a single‐shot spiral readout to quantify B 1 . Results The in vitro and in vivo validations yielded good agreement between the derived spiral VFA B 1 and the acquired reference B 1 maps as well as between the B 1 ‐corrected spiral VFA T 1 and the reference T 1 maps. The spiral VFA acquisitions in the human brain delivered artifact‐free B 1 and T 1 maps and demonstrated high reproducibility at 1.5T and 3T. Conclusion Reliable simultaneous spiral VFA B 1 and T 1 quantification was feasible with acquisition times of 1 min for whole‐brain coverage at clinically relevant resolution.