Noninvasive quantitation of regional myocardial oxygen consumption in vivo with [1-11C]acetate and dynamic positron emission tomography.

Abstract

The usefulness of [1l-tC]acetate as a tracerof overall myocardial oxidative metabolism for use with positron emission tomography has been investigated in 12 closed-chest dogs. Myocardial ltC activity clearance kinetics after intravenous administration of [1-"C]acetate in dogs have been determined noninvasively by positron emission tomography. Biexponential fitting of regional myocardial`C time-activity curves was performed to give clearance half-times and fractional distribution. The rate constant kl for the early rapid phase of "C activity clearance was found to correlate linearly with myocardial oxygen consumption (y=0.0156x+0.039; SEE=0.023; r=0.95). kl was approximately 7% lower in septal sectors compared with the left ventricular free wall, suggesting that regional oxygen consumption in the septum was lower; a concomitant regional attenuation of blood flow in the septum relative to the left ventricular free wall was also observed. In dogs using carbohydrates as the predominant fuel, kl oxygen consumption was somewhat more than in dogs using predominantly free fatty acids (0.021±0.002 compared with 0.018+0.002, p <0.01), indicating that increased carbohydrate consumption is associated with a small increase in kl at constant oxygen consumption. It is concluded that measurement of myocardial [1-"Cjacetate kinetics allows noninvasive determination of cardiac oxygen consumption by positron emission tomography and that the technique is relatively insensitive to myocardial fuel selection. (Circulation 1989;79:134-142) P ositron emission tomography (PET) provides a unique opportunity for the noninvasive study of regional metabolism in vivo.1 While metabolic tracers currently in use for PET are

Abnormal Myocardial Energy-Production State in Mitochondrial Cardiomyopathy and Acute Response to L-Arginine Infusion - C-11 Acetate Kinetics Revealed by Positron Emission Tomography -

“…[10][11][12] As the acetate enters the TCA cycle directly after conversion to acetyl coenzyme A, its clearance can be used to measure the flux of the TCA cycle. This approach makes it possible to determine TCA cycle activity non-invasively.…”

Heterogeneous Reduction of Myocardial Oxidative Metabolism in Patients With Ischemic and Dilated Cardiomyopathy Using C-11 Acetate PET

“…The start of the curve was visually defined corresponding to when the blood-pool activity had cleared (usually 3-5 min) and the curve fitting as automated. [4][5][6][13][14][15]18 The modeling procedure resulted in 16-segment parametric polar maps of acetate clearance (rate constant, Kmono; given in min -1 ). Kmono values of all 16 segments of each measurement were averaged, and then the coefficient of variation (CV) of regional Kmono was derived as a measure of heterogeneity.…”

“…The clearance kinetics of 11 C-acetate, measured by positron emission tomography (PET), can be used to measure tricarboxylic acid cycle flux and thus enable noninvasive quantification of myocardial oxidative metabolism at both the global and regional levels. [2][3][4][5][6][7] The level of myocardial oxidative metabolism with failing LV systolic function has been reported to be comparable to or lower than normal LV function. 8,9 Dyssynchrony is a predictor of poor outcome and may be associated with heterogeneity of myocardial oxidative metabolism in patients with HF.…”

Effects of amino acids on substrate selection, anaplerosis, and left ventricular function in the ischemic reperfused rat heart.

“…An understanding of the quantitative extent of these alterations is important for both diagnosis and therapy in reperfused myocardium. For example, clearance of "C-enriched acetate may be monitored in patients by positron tomography (7)(8)(9), yet the biochemical basis of altered tracer clearance during ischemia is incompletely understood (10)(11)(12). Of perhaps greater significance is the potential for improving recovery after ischemia by deliberately modifying carbon flow into the citric acid cycle.…”