Magnetically enhanced MagMSC retention in the rat heart. (A, B) In vivo MRI T2 fl2d cardiac images at 24 hours after injection. The anterior LV walls of cell-treated animals showed relative hypointensity that was especially obvious in the Mag group. (C, D) In vitro fluorescence images of extracted heart at 24 hours after injection. Significantly escalated fluorescence signals were observed in the Mag group compared with the NonMag group. The PBS group exhibited background signal and was used as a control. (E) Quantitative PCR of the male-specific SRY gene at 24 hours and 3 weeks after cell infusion.