Setting of regions of interest and representative images of CBF, CBV, and MTT. On the CBF map on perfusion CT scans, a round small region of interest was set at the region with decreased CBF in the territory of the lenticulostriate artery (region of interest 1 [ROI-1]). Another region of interest was set in the mirror position to region of interest 1 in the contralateral hemisphere (region of interest 2 [ROI-2]). Using these two regions of interest, CBF, CBV, and MTT were measured. MRI, MR image.