Figure 2.

Figure 2A shows a K^trans vs. v_e error surface. The contour plot shows the chi square statistic, χ² = Σ[S_ref(t) – S_grid(t)]², for simulated DCE-MRI time-courses from parameters equal to the K^trans,v_e coordinates. The χ² value decreases as the contour lines move towards the center of the closed loops. B shows the best k_ep (≡K^trans/v_e) values determined at different β values. A near constant k_ep is observed within the entire β range tested.