Science to Practice: Can MR Imaging Cell Tracking of Macrophage Infiltration Be Used as a Predictive Imaging Biomarker for Transplanted Stem Cell Rejection?

Ferumoxytol-enhanced magnetic resonance (MR) imaging of donor-matched and mismatched stem cell transplants demonstrated decreased signal intensity not only for a xenogeneic mismatch in species but, surprisingly, also for a syngeneic mismatch in sex. MR imaging findings were corroborated with intravital fluorescence microscopy (IVM), where nearly 90% of all ferumoxytol-containing cells were found to be macrophages. Hence, MR imaging cell tracking of infiltrating macrophages may have predictive value in determining whether transplanted stem cell rejection will occur.