title: Assessment of myocardial perfusion by dynamic N-13 ammonia PET imaging: comparison of 2 tracer kinetic models.
abstract: 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.
authors.affiliation: Department of Cardiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria. aliasghar.khorsand@meduniwien.ac.at
authors.forename: Aliasghar
authors.initials: A
authors.lastname: Khorsand
authors.forename: Senta
authors.initials: S
authors.lastname: Graf
authors.forename: Christian
authors.initials: C
authors.lastname: Pirich
authors.forename: Otto
authors.initials: O
authors.lastname: Muzik
authors.forename: Kurt
authors.initials: K
authors.lastname: Kletter
authors.forename: Robert
authors.initials: R
authors.lastname: Dudczak
authors.forename: Gerald
authors.initials: G
authors.lastname: Maurer
authors.forename: Heinz
authors.initials: H
authors.lastname: Sochor
authors.forename: Ernst
authors.initials: E
authors.lastname: Schuster
authors.forename: Gerold
authors.initials: G
authors.lastname: Porenta
mesh_terms: 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
chemical_list: D009590:Nitrogen Radioisotopes; D019275:Radiopharmaceuticals; D000641:Ammonia