Compartment model for measuring myocardial oxygen consumption using [1-11C]acetate.
Although [1-11C]acetate has been validated as a PET tracer for myocardial oxygen consumption (MVO2) in animals and humans, mono- and biexponential fitting of the tissue time-activity curve yields only estimates of MVO2. This study attempts to develop and validate a simple tracer kinetic model in vivo for estimation of regional MVO2.


METHODS
Twenty-seven experiments were performed in 12 anesthetized dogs with [1-11C]acetate and serial PET images under different MBF and MVO2 (baseline, ischemia, xylazine, dobutamine and dipyridamole). Estimates of MVO2 were obtained from dynamic [1-11C]acetate PET and model fitting. MBF was measured by radiolabeled microspheres, and MVO2 was calculated by the Fick method using arterial and coronary blood samples.


RESULTS
The proposed model fitted equally well for all study conditions with a multiple correlation coefficient of 0.985 +/- 0.026. Estimated MVO2 correlated linearly with measured MVO2 (y = 0.033 + 0.690x, r = 0.92, s.e. of estimates = 0.020).


CONCLUSIONS
This study indicates that MVO2 can be assessed with PET and [1-11C]acetate over a wide range with a simple tracer kinetic model.
Sun
K T
KT
Department of Molecular and Medical Pharmacology, UCLA School of Medicine 90095, USA.
Chen
K
K
Huang
S C
SC
Buxton
D B
DB
Hansen
H W
HW
Kim
A S
AS
Siegel
S
S
Choi
Y
Y
Müller
P
P
Phelps
M E
ME
Schelbert
H R
HR
D000085:Acetates / Q000097:blood; D000818:Animals; D001825:Body Fluid Compartments; D002245:Carbon Dioxide / Q000097:blood; D002250:Carbon Radioisotopes; D016009:Chi-Square Distribution; D003198:Computer Simulation; D003326:Coronary Circulation; D004176:Dipyridamole; D004280:Dobutamine; D004285:Dogs; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D008955:Models, Cardiovascular; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D014055:Tomography, Emission-Computed; D014991:Xylazine
D000085:Acetates; D002250:Carbon Radioisotopes; D005230:Fatty Acids, Nonesterified; D002245:Carbon Dioxide; D014991:Xylazine; D004280:Dobutamine; D004176:Dipyridamole