Assessment of myocardial perfusion by dynamic N-13 ammonia PET imaging: comparison of 2 tracer kinetic models.
BACKGROUND
Measurement of myocardial blood flow (MBF) by dynamic nitrogen 13 ammonia (NH(3)) positron emission tomography (PET) uses tracer kinetic modeling to analyze time-activity curves. We compared 2 commonly used models with 2 compartments (2C) and 3 compartments (3C) for quantification of MBF and coronary flow reserve (CFR).


RESULTS
Seventy-seven patients underwent NH(3) PET at rest and during hyperemia. Time-activity curves for blood pool and myocardial segments were obtained from short-axis images of dynamic sequences. Model fitting of the 2C and 3C models was performed to estimate regional MBF. MBF values calculated by 2C and 3C models were 0.98 +/- 0.31 mL.min(-1).g(-1) and 1.11 +/- 0.37 mL.min(-1).g(-1), respectively, at rest (P < .0001) and 2.79 +/- 1.18 mL.min(-1).g(-1) and 2.46 +/- 1.02 mL.min(-1).g(-1), respectively, during hyperemia (P < .01), resulting in a CFR of 3.02 +/- 1.31 and 2.39 +/- 1.15 (P < .0001), respectively. Significant correlation was observed between the 2 models for calculation of resting MBF (r = 0.78), hyperemic MBF (r = 0.68), and CFR (r = 0.68).


CONCLUSIONS
Measurements of MBF and CFR by 2C and 3C models are significantly related. However, quantification of MBF and CFR significantly differs between the methods. This difference needs to be considered when normal values are established or when measurements obtained with different methods need to be compared.
Khorsand
Aliasghar
A
Department of Cardiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria. aliasghar.khorsand@meduniwien.ac.at
Graf
Senta
S
Pirich
Christian
C
Muzik
Otto
O
Kletter
Kurt
K
Dudczak
Robert
R
Maurer
Gerald
G
Sochor
Heinz
H
Schuster
Ernst
E
Porenta
Gerold
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000641:Ammonia; D003198:Computer Simulation; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D009590:Nitrogen Radioisotopes; D049268:Positron-Emission Tomography / Q000379:methods*; D011865:Radioisotope Dilution Technique; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D009590:Nitrogen Radioisotopes; D019275:Radiopharmaceuticals; D000641:Ammonia