SUMMARY
Athersclerotic plaque imaging is currently performed using cardiac MR. However this method is only able to detect late stages of the plaque at which point the plaque is called vulnerable and could rupture leading to stroke or heart attack. It is shown that the addition of contrast agent to cardiac MR atherosclerosis will enhance plaque characterization. To enable early stage plaque imaging, we have a developed a dual modality PET/MR superparamagnetic iron oxide nano particle (SPIO) consisting of an iron oxide core with a functioanalized PEG coating to label 64Cu. The circulation half life of the SPIO is 47 minutes, which is ideal for multimodal imaging of atherosclerotic plaque. The pharmacokinetics of the 64Cu labeled SPIOs were determined by performing biodistribution studies of the particles at 15min, 1, 3, and 24 hours post injection in mice. The organ biodistribution of the SPIOs showed that the amount of the particles staying in the aorta may be enough to enable PET imaging in vivo. The VCAM targeted SPIOs were tested in vivo in a carotid ligated mouse model and showed accumulation in the inflammatory region. Our study suggest that this iron oxide based nano particle can be a promising tool to be used as a multi modal PET/MR contrast agent to aid early stage plaque detection.