Characterization of Viable and Nonviable Myocardium at MR Imaging: Comparison of Gadolinium-based Extracellular and Blood Pool Contrast Materials versus Manganese-based Contrast Materials in a Rat Myocardial Infarction Model

PURPOSE: To determine the contrast agent behavior of gadolinium-based (extracellular and albumin-binding) and manganese-based contrast media for late-enhancement imaging of myocardial infarction. MATERIALS AND METHODS: Coronary ligation was performed in 30 rats, and they were serially imaged with segmented inversion-recovery gradient-echo magnetic resonance (MR) imaging (repetition time msec/echo time msec/inversion time msec [fixed], 5.2/2.5/430; flip angle, 15°) during 1 hour after administration of contrast media by using a 1.5-T MR unit. Serial measurements of the longitudinal relaxation were performed by using the Look-Locker approach (repetition time msec/echo time msec, 1,000/3.5; flip angle, 10°). Detection and size of infarction were evaluated at each time point and compared with end-point histologic findings. RESULTS: For all manganese-based media, the contrast agent cleared from the blood pool rapidly. Manganese-based contrast media allowed precise labeling of viable cardiomyocytes within 30 mi...