A number of radiolabeled fatty acids have been developed to assess
myocardial fatty acid metabolism. Radioactive fatty acid analogues are classified into
PET and SPECT tracers; carbon-11 is the most common isotope for PET, while iodine-
123 is typically used in SPECT. The main approaches for the development in fatty acid
tracers include shift from PET tracers to SPECT tracers, iodine stabilization, and
prolonged retention of tracers in the myocardium. 15-(p-iodophenyl)-3-(R, S)-methyl
pentadecanoic acid (BMIPP), an iodine-123 labeled branched-chain fatty acid
analogue, has been widely available for routine clinical SPECT in Japan, and provides
useful information on abnormal fatty acid metabolism in ischemic heart disease as well
as nonischemic cardiomyopathy. This agent plays a crucial role in the diagnosis of
these diseases, and the prediction of therapeutic effect and prognosis. Reduced BMIPP
uptake than perfusion is often observed in ischemic heart disease such as myocardial
infarction and angina pectoris. This mismatched uptake may reflect ischemic but viable
myocardium, and is associated with stunned or hibernating myocardium. In addition,
BMIPP can serve as a memory marker of transient myocardial ischemia because
BMIPP abnormality may persist even after perfusion recovery following ischemia. On
the other hand, heart-to-mediastinum (H/M) ratio is commonly used as an index of
BMIPP uptake in nonischemic cardiomyopathy. This topic will overview basic
principles and clinical applications of fatty acid metabolic imaging.
Keywords: BMIPP, Fatty Acid Metabolic Imaging, Ischemic Heart Disease,
Nonischemic Cardiomyopathy, SPECT.