In vivo magnetic resonance imaging of mesenchymal stem cells in myocardial infarction.

We investigated the potential of magnetic resonance imaging (MRI) to track magnetically labeled mesenchymal stem cells (MR-MSCs) in a swine myocardial infarction (MI) model. Adult farm pigs (n=5) were subjected to closed-chest experimental MI. MR-MSCs (2.8 to 16x107 cells) were injected intramyocardially under x-ray fluoroscopy. MRIs were obtained on a 1.5T MR scanner to demonstrate the location of the MR-MSCs and were correlated with histology. Contrast-enhanced MRI demonstrated successful injection in the infarct and serial MSC tracking was demonstrated in two animals. MRI tracking of MSCs is feasible and represents a preferred method for studying the engraftment of MSCs in MI.