Rubidium-82 PET imaging is feasible in a rat myocardial infarction model

Abstract

Background. Small-animal myocardial infarct models are frequently used in the assessment of new cardioprotective strategies. A validated quantification of perfusion using a noncyclotron-dependent PET tracer would be of importance in monitoring response to therapy. We tested whether myocardial PET perfusion imaging is feasible with Rubidium-82 ( 82 Rb) in a small-animal scanner using a rat myocardial infarct model.Methods. 18 Sprague-Dawley rats underwent permanent coronary artery ligation (infarct group), and 11 rats underwent ischemia-reperfusion (reperfusion group) procedure.82 Rb-PET and magnetic resonance imaging (MRI) were conducted before and after the intervention. Perfusion was compared to both left ventricle ejection fraction (LVEF) and infarct size assessed by MRI.Results. Follow-up global 82 Rb-uptake correlated significantly with infarct size (infarct group: r 5 20.81, P < 0.001 and reperfusion group: r 5 20.61, P 5 0.04). Only 82 Rb-uptake in the infarct group correlated with LVEF. At follow-up, a higher segmental 82 Rb-uptake in the infarct group was associated with better wall motion (b 5 0.034, CI [0.028;0.039], P < 0.001, R 2 5 0.30), and inversely associated with scar transmurality (b 5 22.4 [22.6; 22.2], P < 0.001, R 2 5 0.59). The associations were similar for the reperfusion group. Conclusion.82 Rb-PET is feasible in small animal scanners despite the long positron range and enables fast and time-efficient myocardial perfusion imaging in rat models. (J Nucl Cardiol 2017) Key Words: Small-animal heart AE rat myocardium AE perfusion imaging AE infarction AE rubidium-82 PET AE magnetic resonance Electronic supplementary material The online version of this article

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