The goal of this project is to develop a nanoscale contrast agent for early detection of vulnerable atherosclerotic plaques. These plaques display a specific biological and cellular composition and present a high risk to rupture causing thrombosis. To achieve our goal, we tailor the design of a nanoprobe for MR imaging of biological markers of plaque vulnerability. The probe will be based on a chemical exchange saturation transfer (CEST) lanthanide. CEST is a promising new MR imaging modality. Using lanthanides, one can generate images by exploiting saturation transfer effects. Currently we perform studies, in silico and in vitro, of combinations of different lanthanide pools present in the same nanoparticle that resonate at different frequencies to achieve optimal contrast to noise ratio.