Figure 4.

Synthetic perfusion and anatomical data. Some aspects of the perfusion data, such as the higher activity at the intersection of the lines, can be deduced from the underlying anatomy (the intersection of the lines), but other aspects of the perfusion data, such as the increased activity on the upper right line, cannot be deduced from the anatomy. 4c,4d: Decomposition of synthetic data using non-rotational invariant features. The constructed features include orientation, so the higher values in the horizontal line are correctly reconstructed. 4e,4f: Reconstructed perfusion and residual perfusion decomposition of Figure 4b. Because orientation invariant features were used, the higher perfusion of the horizontal line is not predicted, but the intersection of the lines does indicate a greater predicted functional signal. Orientation invariance enables greater information sharing across regions, leading to lower variance in the reconstruction as compared to the reconstruction using non-rotationally invariant features (4c).