Fig. 1

Visualizations of computed flow-scaled residue functions for different values of the hyperparameter alpha. We see that for very low alpha (alpha = 0.01) the computed result shows unphysical spikes at later dynamical steps. Even for reasonable small alpha (alpha = 0.3) the computed flow-scaled residue function does not show these spikes. This effect is even more pronounced for high alpha (alpha = 0.8)

x-axis (dynamic): number perfusion-weighted dynamic image obtained per slice. For each slice 40 dynamics were acquired, being acquired 1.6 s apart between each other. Dynamic image 1–9 provide the baseline information, dynamic image 10–40 show contrast medium flow dynamics.

y-axis (value): value of the computed flow-scaled residue function.