Inclusion/exclusion criteria and image randomization process: 50 subjects underwent initial feasibility trial of CTP, of which subjects were excluded because of QCA not being performed (n = 7), or discordance between defect territory between QCA and SPECT (n = 24). Of the remaining 19 subjects, 7 served as controls (ie, no significant defects at SPECT or no evidence of stenosis > 50% by QCA), and 12 served as positive cases (≥ 50% QCA, with a matching, at least moderate perfusion defect in the same territory at SPECT).