Figure 5

Plots of the mean perfusion estimates (left) and the coefficients of variation (CV) (right) of perfusion estimates from all five subjects in the study versus changes in the regularization weight parameter, λ. The average optimal λ value for these perfusion estimates was λ = 0.03. While there may be relatively large changes in perfusion estimates across a broad range of λ values, small deviations from the optimal λ value result in insignificant changes in mean perfusion estimates. This demonstrates that model-independent analysis is relatively insensitive to small deviations from the optimal regularization parameter. The coefficients of variation of the perfusion estimates remained nearly constant over a large range of λ values.