Fig 5. Relative bias of the intracellular lifetime as a function of ΔR₂t_E.

The ratio of τ_i,r/τ_i as a function of ΔR₂t_E, is shown for six different sets of f_e0 and $f_{\mathrm{e}}^{\text{eq}}$ values. The solid blue lines are calculated from Eq 25, while the dashed red lines are calculated from Eq 24. The framed plot shows the bias from low f_e0 and 50% extracellular fraction, which approximately corresponds to our experimental conditions. The vertical dotted line is at ΔR₂t_E = 0.6, which corresponds to echo time t_E = 17 ms and the difference in relaxation rate constants ΔR₂ = 35 s⁻¹. Here the relative bias (solid blue line) is about −20%.