Bias-free T₁ Mapping via Simultaneously Estimating Bloch-Siegert and Magnetization Transfer Effects

Synopsis

T₁ maps obtained using fast steady-state sequences are usually sensitive to B₁⁺ inhomogeneity and MT effects. We propose a novel method to achieve simultaneously B₁⁺- and MT-corrected T₁ quantification by introducing off-resonance RF pulses that create two effects: 1) direct saturation of macromolecules and 2) B₁⁺ dependent Bloch-Siegert phase shift. This method, termed BTS (Bloch-Siegert and magnetization transfer simultaneously), is presented and validated in both simulations and experiments, correcting for T₁ bias induced from B₁⁺ inhomogeneity and MT effects.