<p>(A) Cellular viability was investigated before and after labeling with the <sup>19</sup>F-agent, Cell Sense. Although a statistically significant difference was observed in hMSC after labeling, the viability remained high (>80%) in all experiments. There was no significant difference in mMSC viability. (B) Cellular loading was determined by performing NMR on a known number of cells alongside a reference peak with a known number of <sup>19</sup>F atoms. We observed variation in cellular loading of both hMSC and mMSC between experiments. However, this variation does not affect in vivo <sup>19</sup>F quantification since each transplant was only compared to its specific cellular loading.</p
