Effect of carbon-11-acetate recirculation on estimates of myocardial oxygen consumption by PET.
Mono- and biexponential fitting of myocardial 11C-acetate kinetics does not account for the effect of recirculating 11C activity following intravenous injection of the tracer. A tracer kinetic model comprising two and three compartments was developed to describe intravascular and myocardial 11C-acetate kinetics defined by PET. This model approach including a correction for 11C-metabolites in blood was validated by correlating the model parameter estimates with directly measured oxygen consumption (MVO2) in 11 closed-chest dog experiments over a wide range of cardiac work. The model parameter k2 closely correlated with oxygen consumption (r = 0.94). This approach was subsequently applied to human studies and k2-related to rate-pressure product (PRP). In comparison to conventional monoexponential fitting of 11C-acetate tissue kinetics, the model approach improved the correlation coefficients of scintigraphic MVO2 estimates and PRP values from 0.61 to 0.91. Thus, analysis of myocardial 11C-acetate and clearance kinetics with a tracer kinetic model corrects for recirculating 11C-activity and may provide more consistent estimates of myocardial oxygen consumption.
Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0028.
A
A
Buck
H G
HG
Wolpers
G D
GD
Hutchins
V
V
Savas
T J
TJ
Mangner
N
N
Nguyen
M
M
Schwaiger
D000085:Acetates; D000328:Adult; D000818:Animals; D002250:Carbon Radioisotopes; D004285:Dogs; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006349:Heart Valve Diseases / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D014055:Tomography, Emission-Computed
D000085:Acetates; D002250:Carbon Radioisotopes