fig 1.

ROIs used for the analysis of cerebral perfusion. ROIs were placed on six regions in the brain parenchyma of each hemisphere. The ROIs were obtained from four slices on ¹³³Xe-SPECT scans and from two to four slices from PWI images. ROI 1 corresponded to the left ACA territory, ROI 2 to the left ABZ territory, ROIs 3 and 4 to the left MCA territory, ROI 5 to the left PBZ territory, and ROI 6 to the left PCA territory. ROIs 7 through 12 corresponded to the same territories in the right hemisphere. The ROI setting was consistent between ¹³³Xe-SPECT and PWI. Data from 10 regions were obtained for each patient