Myocardial fatty-acid metabolism (PET imaging)

Class

18F-labeled fatty-acid PET tracer

The heart normally derives most of its energy from the oxidation of fatty acids, switching toward glucose utilization when oxygen delivery is limited, as occurs in ischemia, or when insulin signaling is impaired, as in diabetes. This metabolic flexibility, and its breakdown in disease, can be visualized using positron emission tomography (PET) tracers built from fatty-acid analogs labeled with a radioactive isotope such as fluorine-18. After injection, the tracer is taken up by cardiac muscle cells in proportion to their fatty-acid handling, and the emitted signal is captured by a PET scanner to generate images of regional metabolic activity across the heart muscle (myocardium). Areas of reduced fatty-acid uptake can indicate ischemic or scarred tissue, while diffusely altered patterns may reflect systemic metabolic disease affecting the heart. This approach is broadly relevant to evaluating coronary artery disease, distinguishing viable from non-viable heart muscle after a heart attack, and characterizing metabolic remodeling in conditions such as diabetic cardiomyopathy and certain heart failure syndromes. Unlike anatomical imaging, which shows structure, metabolic PET imaging offers a functional readout of how heart tissue is using energy substrates, information that can complement perfusion or structural studies in guiding the understanding of cardiac disease.