A Rapid, Spiral Based VFA Approach to Simultaneous T1 and B1+ Mapping

Christopher Sica¹, Christopher Collins¹

A method for simultaneous B₁⁺ and T₁ mapping is presented. The proposed method acquires a series of spoiled 3D GRE scans with fixed TR and variable flip angle between scans. A spiral acquisition with off-resonance correction is utilized to speed acquisition. Non-linear fitting is applied to the signal expression M ₀ B₁^- (1-E₁)sin[ FA(λθ, ∆B0) ] / (1 E₁cos[ FA(λθ, ∆B0) ]) to obtain B₁⁺ and T₁. This method is compared to an inversion recovery based method to measure T₁ in a set of doped water tubes, and agreement is on the order of several percent. In-vivo results from this technique are also presented.