Fundamentals and Potential of Magnetic Particle Imaging

Cardiovascular interventions are standard treatment for numerous cardiovascular conditions and require high fidelity imaging tools to accurately visualize both vessels and interventional devices. Currently, digital subtraction angiography (DSA) is the standard method for peripheral arterial angiography. Magnetic particle imaging (MPI) is a new imaging modality, free of ionizing radiation, that utilizes static and oscillating magnetic fields to provide high temporal resolution, sub-millimeter spatial resolution images and high sensitivity. Superparamagnetic iron oxide nanoparticles (SPIOs) are used as tracers in MPI and signals are based on non-linear magnetization characteristics of those SPIOs. Regarding the magnetic moment of used tracers in MPI imaging is much faster in MPI, compared to imaging in CT and MRI. This makes MPI also very attractive for cardiovascular imaging and cardiovascular interventions. First in vivo visualization of a beating mouse heart demonstrated the feasibility of the visualization of the cardiovascular system by MPI. Different scanner designs and acquisition methods have already emerged addressing the requirements of cardiovascular interventions. Early studies have demonstrated MPI as an interesting and promising cardiovascular imaging modality. Technical improvement in hardware MPI imaging systems are currently being addressed in ongoing research which will facilitate former image acquisition with higher resolution in larger animals and/or human.