Magnetic Particle Imaging

MPI was first presented during 2005 and began to come into its own by 2012. So far, only a handful of prototype small-animal MPI scanners have been constructed worldwide. It has the potential to revolutionize the biomedical imaging field. The new tracer imaging modality is gaining significant interest from NMR and MRI researchers. MPI employs the same superparamagnetic iron oxide (SPIO) contrast agents that are sometimes used for MR angiography and are often used for MRI cell tracking studies.

These SPIOs are much safer for humans than iodine or gadolinium. SPIOs in MPI generate positive, bright blood contrast. With this ideal contrast, even prototype MPI scanners can already achieve fast, high-sensitivity, and high-contrast angiograms with millimeter-scale resolutions.

While the physics of MPI differ substantially from MRI, it employs hardware and imaging concepts that are familiar to MRI researchers, such as magnetic excitation and detection, pulse sequences, and relaxation effects.

MPI shows great potential for an exciting array of applications, including stem cell tracking and inflammation imaging in vivo, first-pass contrast studies to diagnose or stage cancer.