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Simultaneous B1 and T1 mapping using spiral multislice variable flip angle acquisitions for whole-brain coverage in less than one minute
{Purpose: Variable flip angle (VFA)-based T1 quantification techniques are highly sensitive to B1 inhomogeneities and to residual T2 dependency arising from incomplete spoiling. Here, a rapid spiral VFA acquisition scheme with high spoiling efficiency is proposed for simultaneous whole-brain B1 and T1 mapping. Methods: VFA acquisitions at 2 different flip angles are performed to quantify T1 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 B1. Results: The in vitro and in vivo validations yielded good agreement between the derived spiral VFA B1 and the acquired reference B1 maps as well as between the B1-corrected spiral VFA T1 and the reference T1 maps. The spiral VFA acquisitions in the human brain delivered artifact-free B1 and T1 maps and demonstrated high reproducibility at 1.5T and 3T. Conclusion: Reliable simultaneous spiral VFA B1 and T1 quantification was feasible with acquisition times of \textless1 min for whole-brain coverage at clinically relevant resolution.}
@article{item_3008639, title = {{Simultaneous B1 and T1 mapping using spiral multislice variable flip angle acquisitions for whole-brain coverage in less than one minute}}, journal = {{Magnetic Resonance in Medicine}}, abstract = {{Purpose: Variable flip angle (VFA)-based T1 quantification techniques are highly sensitive to B1 inhomogeneities and to residual T2 dependency arising from incomplete spoiling. Here, a rapid spiral VFA acquisition scheme with high spoiling efficiency is proposed for simultaneous whole-brain B1 and T1 mapping. Methods: VFA acquisitions at 2 different flip angles are performed to quantify T1 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 B1. Results: The in vitro and in vivo validations yielded good agreement between the derived spiral VFA B1 and the acquired reference B1 maps as well as between the B1-corrected spiral VFA T1 and the reference T1 maps. The spiral VFA acquisitions in the human brain delivered artifact-free B1 and T1 maps and demonstrated high reproducibility at 1.5T and 3T. Conclusion: Reliable simultaneous spiral VFA B1 and T1 quantification was feasible with acquisition times of \textless1 min for whole-brain coverage at clinically relevant resolution.}}, volume = {81}, number = {3}, pages = {1876--1889}, publisher = {Wiley-Liss}, address = {New York}, year = {2019}, slug = {item_3008639}, author = {Heule, R and Pfeuffer, J and Meyer, CH and Bieri, O} }