A, ROIs that were drawn in the flow territories of the anterior cerebral artery (cortex: ROIs 1 and 2, basal ganglia: ROIs 5 and 6) and the middle cerebral artery (cortex: ROIs 3 and 4, basal ganglia: ROIs 7 and 8). A, ROIs that were drawn in the flow territories of the anterior cerebral artery (cortex: ROIs 1 and 2, basal ganglia: ROIs 5 and 6) and the middle cerebral artery (cortex: ROIs 3 and 4, basal ganglia: ROIs 7 and 8). B, In the periventricular white matter, ROIs were drawn anterior (ROIs 9 and 10) and on either side (ROIs 11 and 12) of the lateral ventricles. C.J.J. van Asch et al. AJNR Am J Neuroradiol 2010;31:67-70 ©2010 by American Society of Neuroradiology