Use of the metabolic tracer carbon-11-acetate for evaluation of regional myocardial perfusion.

Abstract

The high first-pass myocardial extraction fraction of carbon-11-acetate suggests that its initial uptake depends on blood flow. Accordingly, regional uptake of 11C-acetate at 4 min was compared to regional perfusion determined with nitrogen-13-ammonia in 119 segments in 15 patients with stable coronary artery disease by two methods. A close correlation was observed between initial relative myocardial concentrations (segmental activity normalized to maximal activity) of both tracers (11C-acetate = 0.88; 13N-ammonia + 0.079; s.e.e. = 0.064, r = 0.94, p less than 0.001). Furthermore, segmental net extractions (E.F), as calculated from the input function and segmental activities, of the two tracers correlated closely by E.FC-11 = 0.55E.FN-13 + 0.080 (s.e.e. = 0.045, r = 0.87, p less than 0.001). These relationships indicate that initial regional myocardial uptake of 11C-acetate reflects perfusion and that 11C-acetate permits near simultaneous evaluation of regional oxidative metabolism and of regional myocardial perfusion.