In vivo 19F MR inflammation imaging after myocardial infarction in a large animal model at 3T.

Abstract

Fluorine-19 (19F) MRI with intravenously applied perfluorocarbons allows the in vivo monitoring of infiltrating immune cells as demonstrated in small animal models at high field. Here, we aimed to transfer this approach to a clinical scanner for detection of inflammatory processes in the heart after acute myocardial infarction (AMI) in a large animal model. Optimization of coil and sequence performance was carried out on phantoms and in vivo at a 3T Philips Achieva. AMI was induced in Munich mini pigs by 90-min occlusion of the left anterior descending artery. At day 3 after AMI, pigs received a body weight-adjusted intravenous dose of a perfluorooctyl bromide nanoemulsion followed by 1H/19F MRI at day 6 after AMI. A balanced steady-state free precession turbo gradient echo sequence using an ellipsoidal 19F/1H surface coil provided the best signal-to-noise ratio and a superior localization of 19F patterns in vivo. This approach allowed the reliable detection of 19F signals in the injured myocardium within less than 20min. The 19F signal magnitude correlated significantly with the functional impairment after AMI. This study demonstrates the feasibility of in vivo 19F MR inflammation imaging after AMI at 3T within a clinically acceptable acquisition time.