Composite Contrast Approach for Cellular MRI using the Combination of Gadolinium Chelates and Iron Oxide Particles

There are growing interests of molecular and cellular imaging. A number of imaging modalities have been developed for acquiring biological information. Magnetic resonance imaging (MRI) is an excellent method for observing brain function and bio/molecular information with noninvasive and in-vivo state and for excellent anatomical resolution. Contrast agent gives plentiful ability to MR imaging through signal enhancement and functional detection. Gadolinium chelates and superparamagnetic iron oxide particles (SPIOs) are widely used MR contrast agents that have different relaxation properties of positive and negative contrasts respectively. We suggested a method exhibiting both contrast characteristics by using two contrast agents with aqueous mixture. We performed MR imaging for measuring the relaxation effects of composite samples and demonstrated the attainable dual-contrast characteristics within appropriate concentration. The method may overcome the present limitation of cellular MRI using SPIO and be applied to cell labeling with tuneable contrast for cell therapy and regenerative medicine.