PLANAR MYOCARDIAL IMAGING IN THE BABOON MODEL WITH IODINE-123-15-(IODOPHENYL)PENTADECANOIC ACID (IPPA) AND NE-123-15-(P-IODOPHENYL)-3-R,S-METHYLPENTADECANOIC ACID (BMIPP), USING TIME-ACTIVITY CURVES FOR EVALUATION OF METABOLISM

The purpose of this study was to compare by planar myocardial scintigr aphy the kinetics of iodine-123-15-(iodophenyl)pentadecanoic acid (I-1 23-pPPA and I-123-oPPA), and of odine-123-(p-iodophenyl)-3-R,S-methylp entadecanoic acid (BMIPP), firstly in normal baboons, and subsequently after blocking fatty acid oxidation by a carnitine palmitoyl transfer ase I(CPT1) inhibitor. The induced changes in myocardial metabolism we re reflected in the dynamic behaviour of the three tracers. pPPA and o PPA to a large extent, provided information on beta-oxidation changes in the myocardium: beta-oxidation participation changed from 47% and 5 0%, respectively to 17% and 23% after inhibition. BMIPP provided bette r images and reflected largely on changed tracer incorporation into th e neutral lipid pools. The beta-oxidation contributed only about 10% t owards the metabolic pathway of BMIPP. The information obtained in thi s study could help determine the tracer of choice for SPECT, whereby m yocardial viability could optimally be revealed.