Design and Characterization of Magnetic Resonance Imaging Gene Reporters

We review the current status for magnetic resonance contrast agents that are designed to act as gene reporters. The basic concepts behind magnetic resonance and contrast enhancement are discussed, and factors that influence design of activatable contrast agents are presented. Several designs for magnetic resonance imaging (MRI) gene reporters are described, including contrast agents that are activated by β-galactosidase, and marker genes that code for proteins that sequester iron. Methods to characterize the uptake and delivery of contrast agents are outlined.