Perfusable tissue index (PTI) is a marker of myocardial viability and requires acquisition of transmission, (15)O-CO, and (15)O-H(2)O scans. The aim of this study was to generate parametric PTI images from a (15)O-H(2)O PET/CT scan without an additional (15)O-CO scan.
Methods: Data from 20 patients undergoing both (15)O-H(2)O and (15)O-CO scans were used, assessing correlation between PTI based on (15)O-CO (PTI(CO)) and on fitted blood volume fractions (PTI(Vb)). In addition, parametric PTI(Vb) images of 10 patients undergoing (15)O-H(2)O PET/CT scans were generated using basis-function methods and compared with PTI(Vb) obtained using nonlinear regression. Simulations were performed to study the effects of noise on PTI(Vb).
Results: Correlation between PTI(CO) and PTI(Vb) was high (r(2) = 0.73). Parametric PTI(Vb) correlated well with PTI(Vb) obtained using nonlinear regression (r(2) = 0.91). Simulations showed low sensitivity to noise (coefficient of variation < 10% at 20% noise).
Conclusion: Parametric PTI images can be generated from a single (15)O-H(2)O PET/CT scan.