[Myocardial imaging using PET and SPECT].

Positron emission tomography (PET) has been used for quantitative analysis of regional myocardial blood flow and metabolism in vivo in these patients. Ischemic myocardium can be identified as an area of enhanced F-18 fluorodeoxyglucose (FDG) uptake as a marker exogenous glucose utilization. Because of limited availability of PET studies, a number of modified methods have been introduced for metabolic imaging in vivo. I-123 betamethyl iodophenyl pentadecanoic acid (BMIPP) has been used to probe free fatty acid metabolism using SPECT cameras. Ischemic myocardium has been identified as an area of reduced BMIPP uptake, probably due to altered metabolism in repetitive ischemic episodes. Such reduction of BMIPP uptake is more likely seen in patients with unstable angina or vasospastic angina where regional wall motion abnormalities are associated. In addition, severely ischemic myocardium has been identified as an areas of reduced uptake of I-123 metaiodobenzyl guanidine (MIBG) as a marker of adrenergic neuronal function. These biochemical imaging should be valuable for identifying severely ischemic myocardium and assessing severity of ischemic insult.