Fig. 1

Overall framework of proposed CMR oximetry technique. The graph depicts the simulation of the L-M model (described in gray box at top of the figure, adapted from [14]). The transverse relaxation time of blood is plotted as a function of O2 saturation ( %SbO ₂) and inter-echo spacing (τ ₁₈₀). Other parameters used in the simulation were: Hct = 0.41, T _2O = 300 ms, α = 0.545 ppm, and τ _ex = 3 ms. Four different T2 maps, each with a fixed τ ₁₈₀ at 12, 15, 20, and 25 ms, were acquired to generate a set of equations for the L-M model relating T2 and O2 saturation. The data, along with known Hct and arterial O2 saturation, are jointly processed by NLLS curve fitting to estimate the unknown parameters - venous O2 saturation, α, τ _ex , and T _2O