First in vivo MPI of lung perfusion in rats

Researchers in the US have invented an imaging agent that allows magnetic particle imaging (MPI) of lung perfusion in rats. The test bodes well for the clinical use of MPI, which unlike other lung-imaging techniques delivers no ionizing radiation and only requires small amounts of the agent to be injected.

MPI is an emerging imaging technique that forms direct images from the location of superparamagnetic iron oxide nanoparticles (SPIOs) injected into the bloodstream. The images are high contrast because they rely on electronic rather than nuclear magnetization as in nuclear MRI; but unlike other high-contrast imaging techniques, such as PET, CT and X-rays, they require no ionizing radiation.

MPI scanners themselves are in the early stages of commercialization. Meanwhile, Steven Conolly and Xinyi Zhou of UC Berkeley and others have developed the first MPI agent for imaging a particular organ, the lungs. The agent is an aggregate of SPIOs and macroaggregated albumin (MAA), the latter of which has already been used in nuclear medicine studies of the lungs because it is several times thicker than a lung’s capillaries. “In those studies, radiotracers are incorporated into the MAA to produce an image,” says Zhou. “Hence, we came up the idea to incorporate SPIOs into the MAA to produce an MPI lung image.” […]

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