CEST-MRI studies of cells loaded with lanthanide shift reagents.

Cells can be visualized by CEST MRI after loading with paramagnetic shift reagent, by exploiting the large ensemble of the properly shifted intracellular water molecules. A better performance is obtained when the complexes are entrapped inside the endosomes. The observed (δIn ) value is strongly correlated to the chemical nature of the probe, and to its concentration and cellular localization. Two applications of this method are reported in this paper: (1) for in vivo cell visualization and (2) for the monitoring of the cellular proliferation process, as this method is accompanied by a change in δIn that may be exploited as a longitudinal reporter of the proliferation rate.