Iodine-123 phenylpentadecanoic acid: Detection of acute myocardial infarction and injury in dogs using an iodinated fatty acid and single-photon emission tomography

The ability of an iodinated fatty acid, iodine-123 Phenylpentadecanoic acid (1-123 PPA), and single-photon emission computed tomography (SPECT) to detect myocardium injured by temporary or permanent coronary arterial occlusion was evaluated. In 5 control dogs, 11 dogs that underwent 90 to 120 minutes of fixed left anterior descending coronary artery (LAD) occlusion, and 8 dogs that underwent 90 minutes of temporary LAD occlusion and up to 90 minutes of reflow, 2 to 6 mCi of 1-123 PPA were injected and the dogs were imaged with SPECT. Control dogs showed relatively uniform uptake and clearance of 1-123 PPA in similar left ventricular (LV) regions. Dogs with permanent LAD occlusion were identified by computer algorithm as having regions of decreased 1-123 PPA uptake in the infarct-related area and a reduced rate of 1-123 PPA clearance (-9.4% in infarct sectors [washin], +3.7% in sectors adjacent to the area of infarction, and +15.4% in control LV sectors [p <0.01]). Dogs with temporary LAD occlusion and reperfusion had decreased clearance of 1-123 PPA from the regions with infarction; 1-123 PPA clearance was -5.2 ± 16.4% in infarct sectors, 12.7 ± 7.4% in periinfarct zones, and 30.4 ± 12% in control LV regions. These data demonstrate that tomographic analysis of 1-123 PPA uptake and clearance permits the relatively noninvasive detection of LV myocardium injured by permanent or temporary LAD occlusion and reperfusion.