Fig 1. Regions of interest drawn in a PWI (A) and MTT map (B). The regions of interest were placed on cortical regions in the medial frontal lobe in the ACA distribution, in the posterior frontal lobe in the MCA distribution and in the occipital lobes in the PCA distribution as well as in the putamen in each cerebral hemisphere. To calculate the MTTs in the frontal lobes, as well as in the basal ganglia, an AIF (blue dot) was obtained from an ipsilateral MCA branch to represent anterior circulation. In calculating MTT in the occipital lobe, an AIF (yellow dot) was obtained from an ipsilateral PCA branch. This MTT map (B) was calculated with the AIF obtained from the right MCA branch.