A demonstration <i>in vivo</i> cellular MRI using the simple labeling method.

<p>A rat with glioma was transplanted with SPION-labeled NPCs into the lateral ventricle, and T2WIs were used to track the migration and distribution of the transplanted NPCs. (A) T2WI acquired at baseline, on day 1, 7, and 14 after transplantation. Hypointensities were readily visible one day later, and persisted throughout the tracking duration. (B) Signals at the tumor or injection site in relation to a control area (the cortex) were plotted against time. (C) PB staining confirmed the relocation of SPION-labeled cells following transplantation. Histology was performed on brain tissues obtained on day 14 after transplantation. The white arrow indicates the location of the tumor whereas the red arrows indicate the hypointensity arising from the labeled NPCs. For tumors without injected NPCs, the signal patterns were different. Untreated ENU tumors exhibited only mild hypointensities likely associated with hemorrhage on T2WI and T2*WI.