Cardiac Metabolism in a Pig Model of Ischemia-Reperfusion by Cardiac Magnetic Resonance with Hyperpolarized 13C-Pyruvate

Background: Magnetic resonance (MRI) with hyperpolarized C-13-pyruvate is a new technique for the assessment of myocardial metabolism. Aims: The aim of this study is to assess the effectiveness of MRI with hyperpolarized C-13-pyruvate to detect cardiac metabolic changes in a model of ischemia/reperfusion. Methods: A pneumatic occluder was placed around the left anterior descending artery in 7 pigs. A 3 T scanner with a C-13 quadrature birdcage coil was used. Hyperpolarized C-13-pyruvate was injected intravenously at rest, during coronary occlusion and 5 min after reperfusion. Metabolic images were acquired using a 3D-IDEAL spiral CSI during the injection of C-13-pyruvate and 3D-parametric maps of C-13-pyruvate, C-13-lactate and C-13-bicarbonate were generated. Metabolic Activity Mismatch (MAM) was defined as the relative change between a) resting state and coronary occlusion or b) resting and reperfusion in all the myocardial segments. Results: During occlusion, a decrease in C-13-lactate (-21 +/- 26% vs baseline 3 +/- 16%, P < 0.0001) and C-13-bicarbonate (-29 +/- 34% vs 33 +/- 52%, P < 0.0001) was found in myocardial segments at risk, as compared with remote segments. In ischemic segments, the C-13-lactate signal increased during reperfusion (20 +/- 42% vs -7 +/- 22%, P = 0.0007), while C-13-bicarbonate was persistently reduced (-38 +/- 27% vs 36 +/- 51%, p < 0.0001). Conclusions: C-13-pyruvate MRI is able to detect transient changes in regional metabolism in an in-vivo model of myocardial ischemia-reperfusion. (C) 2015 The Authors. Published by Elsevier Ireland Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).