(a–c) Monte Carlo simulations of the SD in T1(with T2 =80ms), and (d–f) T2 (with T1 =1s) with an SNR of 50, and 100 runs. Part (a) and (d) show results for the ‘Dual-τ Dual-FA’ method with TR=0.609s, τ3=2τ2 =20ms, and B1 =13.5uT. Part (b) and (e) show results for the ‘Dual-τ Dual-TR’ method with TR2 =2TR1 =1.06s, τ2 =2τ1=20ms, B1 =20uT. Part (c) and (f) are for the ‘Four-FA’ method with TR=0.6s, TR4 =1.032s, τ=20ms, B1 =20uT over a larger T2 range.