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FIGURE 3. Display of relative activity distribution for Markovian homogeneity analysis, where each square panel corresponds to quadrants of the same 3 people illustrated in Figures 1 and 2. Quadrant squares indicate the area of heterogeneity analysis with the basal 4 slices and apex excluded from analysis as described. For the first rest–stress pair of the healthy control person (A), resting homogeneity index is 0.80 at rest and 0.83 after dipyridamole, both within normal limits of 50 healthy control subjects. For the second rest–stress pair of the person with a severe stress-induced perfusion defect (B), the homogeneity index is 0.34 at rest that is < 2 SD of healthy reference subjects and improves to 0.49 after dipyridamole, within 1 SD of healthy reference subjects, despite a severe stress-induced perfusion defect. For the third rest–stress pair of the person with a minimal perfusion abnormality (C), the homogeneity index is 0.26 at rest and improves to 0.40 after dipyridamole with an abnormal base-to-apex longitudinal perfusion gradient but no severe regional stress-induced perfusion defect.
