Fig. 2

Simulation results of the investigation of quantification errors. The signal of the first acquisition S₁ was calculated using Bloch simulations for realistic in vivo parameters (A). An individual steady state \({\mathrm{S}}_{1}^{\mathrm{SS}}\) is reached for each SL time. When using small flip angles, more repetitions are required for this. In B the values were fitted with the common monoexponential model. The relaxation time T_1ρ* calculated in this way is systematically below the true T_1ρ value. The relationship between the systematic underestimation and the two parameters T₁ and T_rec is shown in C. From this it can be seen that an incomplete spin recovery is the decisive point. A systematic error of − 2% to − 16% is to be expected in vivo. If the corrected fit is used (novel signal equation), errors only arise if incorrect sequence parameters are assumed (D). The error propagation is moderate here, since ± 5% estimation errors in the sequence parameters only lead to ± 1.447% errors in T_1ρ