Cahill, K.S., Germain, S., Byrne, B.J. et al. Int J Cardiovasc Imaging (2004) 20: 593. doi:10.1007/s10554-004-3902-8
Background: Magnetic resonance imaging (MRI) of magnetically labeled stem cells is a non-invasive approach that can provide images with high spatial resolution. We evaluated the ability of a commercially available, Food and Drug Administration (FDA) approved contrast agent to allow the monitoring of myoblast transplants in the rodent heart. Methods and Results: Primary rat myoblasts were efficiently labeled by incubation with ferumoxide–polycation complexes and labeled cells retained their normal capacity to generate mature myotubes. Intra-cellular iron-oxide accumulation resulted in MRI contrast changes, allowing for three-dimensional, non-invasive detection of labeled cells in the rodent myocardium. Histological analysis of hearts injected with labeled myoblasts or control, non-viable myoblasts revealed that areas of MRI contrast changes corresponded to iron contained within engrafted myotubes and scavenger cells up to two months post-injection. Conclusions: The high sensitivity of MR imaging will allow for non-invasive studies of cardiac stem cell migration and homing. Additional techniques are in development to non-invasively determine stem cell engraftment rates, viability and differentiation.