Seeing is believing: tracking cells to determine the effects of cell transplantation.

Stem cell therapy holds promise as a therapeutic option for cardiovascular disease. As the field of cellular transplantation matures, novel methodologies are needed to longitudinally track and evaluate the functional effects of transplanted cells. At present, available techniques that hold the greatest promise for tracking cell fate include radionuclide labeling, ferromagnetic particle labeling, and genetic modification with reporter genes. This review describes the benefits and limitations of each technique and provides a summary of critical issues regarding stem cell transplantation that have been addressed by each imaging modality.