Objective
11C-acetate has been applied for evaluation of myocardial oxidative metabolism and can simultaneously estimate myocardial blood flow (MBF). We developed a new method using two-parameter spillover correction to estimate regional MBF (rMBF) with 11C-acetate PET in reference to MBF derived from 15O-H2O PET. The usefulness of our new approach was evaluated compared to the conventional method using one-parameter spillover correction.
Methods
Sixty-three subjects were examined with 11C-acetate and 15O-H2O dynamic PET at rest. Inflow rate of 11C-acetate (K1) was compared with MBF derived from 15O-H2O PET. For the derivation, the relationship between K1 and MBF from 15O-H2O was linked by the Renkin-Crone model in 20 subjects as a pilot group. One-parameter and two-parameter corrections were applied to suppress the spillover between left ventricular (LV) wall and LV cavity. Validation was set using the other 43 subjects’ data. Finally, rMBFs were calculated using relational expression derived from the pilot-group data.
Results
The relationship between K1 and MBF derived from 15O-H2O PET was approximated as K1 = [1–0.764 × exp(−1.001/MBF)] MBF from the pilot data using the two-parameter method. In the validation set, the correlation coefficient between rMBF from 11C-acetate and 15O-H2O demonstrated a significantly higher relationship with the two-parameter spillover correction method than the one-parameter spillover correction method (r = 0.730, 0.592, respectively, p < 0.05).
Conclusion
In 11C-acetate PET study, the new two-parameter spillover correction method dedicated more accurate and robust myocardial blood flow than the conventional one-parameter method.