Regional assessment of myocardial metabolic integrity in vivo by positron-emission tomography with 11C-labeled palmitate.

Abstract

To determine whether positron emission tomography (PET) after the combined administration of 11C-palmitate i.v. to image myocardium and 11CO by inhalation to image the cardiac blood pool with 11CO-Hb provides quantitative delineation of the locus and extent of myocardial infarction, 28 patients with suspected myocardial infarction were studied. Patients [21] had ECG documented transmural infarction and in 7, the diagnosis of infarction was ultimately excluded based on enzymatic and electrocardiographic criteria. To assess reproducibility, 4 patients were studied on 2 occasions 1 mo. apart. Inferior and apical infarcts were readily localized with sagittal and coronal as opposed to transaxial reconstructions. Complete ECG and tomographic concordance was observed for the locus of all transmural infarcts. Reproducibility of tomographic estimates was within 10%. Tomographic estimation of the extent of infarction with 11C-palmitate in a subset of patients in whom right ventricular contributions to overall enzyme release could be excluded was facilitated by delineation of the endocardial border with the 11CO-Hb cardiac blood pool image in the same plane. The correlation between enzymatic and tomographic estimates of infarct size was close (r = 0.92). PET with 11C-palmitate permits quantification and localization of myocardial infarcts in patients.