Fatty Acids and Their Analogs for Myocardial Imaging and Metabolism

摘要

The straight chain radiolabeled fatty acid (FA) show relatively rapid myocardial washout since they could be metabolized by the beta-oxidation and undergo in vivo deiodination. The high levels of free radioiodide in blood requires a special background correction. The use of p-iodo-phenylpentadecanoic acid stabilizes the iodine on the aromatic ring and lowers the amount of free iodide in the blood. This agent was evaluated in many patients, however, translocation of activity from the heart is evident, not as a result of deiodination but as p-Iodo-benzoic acid as a metabolite. To determine whether an analogue designed to inhibit the FA beta-oxidation metabolic process in the myocardium could be a valuable tracer for assessing the myocardial metabolic integrity, we synthesized 1- sup 14 C-beta-methylheptadecanoic acid ( sup 14 C-BMHDA), a FA analogue. Biodistribution of sup 14 C-BMHDA was determined in rats (groups of six) in 5 tissues and blood at 5, 15, 30 and 60 minutes and compared to sup 14 C-palmitic acid ( sup 14 C-PA) a normal FA. A heart concentration of 2.82 and 4.18% I.D./gr at 5 and 60 minutes was observed for sup 14 C-BMHDA, while sup 14 C-palmitic acid was 2.65 and 0.89% I.D./gr at 5 and 60 minutes, respectively. 1 ref., 1 tab.