Simulating the efficiency of Variable Flip Angle (VFA) multi-parametric mapping of T1, PD, and T2* at 7T suggests longer TRs may be optimal

Quantitative MRI at 7T may have important clinical applications owing to the potential for enhanced resolution and uniform tissue characterisation. Current protocols, often for pragmatic reasons, use short TRs(~20ms) and a handful of echo times but this might not be optimal for T2* estimation. We simulated the optimal TR and echo number for dual flip angle mapping of T1, PD, and T2* for realistic 7T tissue and sequence parameters. The optimal efficiency was found to be at 65ms with 20 echoes. The simulations suggested that longer TRs of 40-60ms would be optimal. Preliminary in-vivo data only partially supported these findings