Figure 2

L-curve plots for each of the five subjects in the study. Each of the L-curves was computed for one representative region of the 6-region data in each of the five subjects at rest. These L-curves were typical of the L-curves computed from multiple regions of tissue enhancement in all five subjects. The dark marker at the region of maximum curvature on each L-curve represents the optimal value of λ that provides a near optimal balance of the goodness-of-fit of the estimated tissue enhancement curves and the temporal smoothness of h(t). The optimal 6-region λ values for the five subjects were: λ = 0.032, 0.032, 0.042, 0.028, 0.02.