Early uptake of 99mTc-C2A in the acute phase of myocardial infarction as a prognostic indicator for follow-up cardiac dysfunction

Objective The C2A domain of Synaptotagmin I is a molecular probe for the specific imaging of cell death. Here we test the hypothesis that the uptake of Tc-99m-C2A in the acute phase of an infarction is associated with cardiac dysfunction in follow-ups. Methods The left coronary artery was occluded in Sprague-Dawley rats for 0, 10, 20, and 30 min. Tc-99m-C2A was injected intravenously at 2 h of reperfusion. Anterior planar images were acquired with one million counts on a 7 camera 3 h after injection. Tc-99m-C2A uptake was calculated as the total counts in the left ventricle region minus blood pool signal. The in-vivo signal detected was correlated with wall motion score index at 1 and 3 weeks follow-ups measured by echocardiography. Results Tc-99m-C2A uptake was higher with increased ischemic time (2244 +/- 852, 4054 +/- 1223, and 6178 +/- 1451 for 10, 20, and 30 min ischemia, analysis of variance P<0.001). A significant correlation was found between 99mTc-C2A uptake and wall motion score index at 1 week (R=0.800, P=0.0006) and 3 weeks (R=0.810, P=0.0008). Conclusion In this ischemia/reperfusion model, Tc-99m-C2A uptake in the acute phase was associated with functional abnormality at 1 and 3 weeks. This demonstrates the potential diagnostic and prognostic value of Tc-99m-C2A as a novel imaging agent.