Basic kinetics of 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) in canine myocardium

BMIPP is a radioiodinated fatty acid analogue used for myocardial single photon emission CT (SPECT) imaging based on high cardiac fatty acid metabolism. In normal dogs, 74% of the injected BMIPP was instantly extracted and was then retained in 65.3%. The washout of the retained radioactivity was low, and most of the washout was alpha- and beta-oxidation metabolites. ATP concentration plays an important role in the myocardial uptake and retention of BMIPP. The ATP-dependent BMIPP uptake at the TG pool was strongly regulated by etomoxir with modifying mitochondrial beta-oxidation and subsequent ATP production. Thus, myocardial viability was reflected on the BMIPP uptake in acute ischemia. In spite of insignificant changes in early extraction and retention, BMIPP back diffusion (r = -0.92) and full-oxidation metabolite (r = 0.78) were correlated with the severity of ischemia. Mismatched region of BMIPP with flow (Tl-201) showed decreased metabolic enzymes such as citrate synthase and 3-hydroxyacyl-CoA dehydrogenase. These data suggest that BMIPP would be feasible for detecting cellular energy state from lipid metabolism.