[Myocardial distribution of iodine-123-iodophenyl-9-methyl-pentadecanoic acid (9MPA) in patients with acute myocardial infarction: comparison with regional wall motion obtained from technetium-99m-sestamibi gated SPECT].

123I-iodophenyl-9-methyl-pentadecanoic acid (9MPA) is a modified long-chain (15 carbons) fatty acid with a methyl branch on its 9 carbon location. Myocardial SPECT images (two sets, 10 min each) were obtained starting 10 min (early phase) and 50 min (delay phase) after the injection of 160 MBq 123I-9MPA at rest in 10 patients with acute myocardial infarction. The segmental myocardial uptake (% uptake) and clearance (% washout) from early to delay image were calculated by the SPECT data. ECG-gated myocardial SPECT with 99mTc-sestamibi was also performed and segmental left ventricular (LV) wall motion was evaluated using QGS (quantitative gated SPECT) program. The % uptake of LV segments with hypokinetic or akinetic wall motion were significantly lower than those with normokinesis (p < 0.01) for both early and delay phases. The % washout of hypokinetic segments were significantly lower than those of normokinetic regions (p < 0.01), while the % washout of akinetic segments were significantly higher than those of severely hypokinetic segments (p < 0.05). Thus, 123I-9MPA myocardial distribution and clearance thought to be associated with left ventricular regional wall motion.