Simplified quantification of ¹³N-ammonia PET myocardial blood flow: A comparative study with the standard compartment model to facilitate clinical use

Background: Short imaging protocol to quantify myocardial blood flow (MBF) and myocardial flow reserve (MFR) may enhance the clinical application of ¹³N-ammonia cardiac PET. We assessed the flow quantitation of ¹³N-ammonia PET implementing simple retention model and two-compartment model. Methods: Fourteen healthy volunteers (HVT) and twenty-three clinical patients received ¹³N-ammonia PET/CT. The simple retention model used the first 7-minute image to quantify MBF. Global and regional MBF and MFR of the two models were compared. Results: Global and regional MBF and MFR of these two models were highly correlated with mildly inferior correlation in RCA territory (global R²: rest MBF = 0.79, stress MBF = 0.65, MFR = 0.77; regional R²: rest MBF ≥ 0.72, stress MBF ≥ 0.52, MFR ≥ 0.68). There were significant differences for MFR (4.04 ± 0.72, 3.66 ± 0.48, p = .02) and rest MBF (0.69 ± 0.12, 0.78 ± 0.12, p = .02) between the two models in the HVT group. Conclusions: ¹³N-ammonia global and regional MBF and MFR from the simple retention model demonstrate strong correlations with that from the two-compartment model. Significant differences of MFR and rest MBF are noted in the HVT group, with a proposed normal reference value for the ¹³N-ammonia short simple retention protocol.