For each selected superior vein, the locations in each slice containing branches of that vein were identified using the QSM-venogram and combined. The combined perfusion source maps were overlaid on the corresponding sections of the QSM-venogram, illustrating the dynamics of the selected veins. Perfusion source maps are displayed at average mixing times of 450 ms, 850 ms, and 1250 ms, derived by averaging across consecutive mixing times (400-500 ms, 800-900 ms, and 1200-1300 ms). The positions of the three imaging slices are also shown. While the two larger veins (green and yellow) have branches visible across all three imaging slices, the smaller vein (blue) is covered only by the top two slices. Source data are provided in ref. 54 .
