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Acquired Real time in vivo images of a mouse heart with magnetic particle imaging!

A new tomographic imaging modality took a step forward when researchers showed they were able to acquire in vivo images of a beating mouse heart with high temporal and spatial resolution . It is a technique that has the potential to improve detection from a real-time point of view and from a resolution point of view.

Investigators showed that the three-dimensional real-time magnetic particle imaging (MPI) scans provided anatomic details of a beating heart, including the four heart chambers, using a commercially available MRI contrast agent. The findings are an advance over earlier studies, where only dynamic two-dimensional images of inanimate objects were obtained.

The study is equivalent to the first images of the heart obtained by MRI roughly 20 years ago. MPI relies on the principle of direct visualization of ion particles when injected, whereas in conventional MRI the image is created with an indirect effect caused by the injected contrast agent. Upon injection in the blood, nanoparticles appear as bright signals in the images, from which nanoparticle concentrations can be calculated. The scans capture dynamic concentration changes as the nanoparticles make their way through the bloodstream, and will, theoretically, allow researchers to assess coronary blood flow, myocardial perfusion, ejection fraction, and other measures. In this in vivo study by Weizenecker and colleagues, the team obtained MPI scans in 18 mice. To relate the MPI to the mouse anatomy, reference magnetic resonance images of the mice were acquired after the MPI scans.

The iron-oxide-based nanoparticles injected into the subject, for use in cardiovascular studies, which will provide high-resolution images. These nanoparticles require a certain magnetic core size, blood half-life, and other attributes to be optimized for use with MPI.

The images are obtained very quickly, much faster than with conventional MRI, and the technique provides the same spatial resolution achieved with computed tomography (CT) and MRI, as well as high sensitivity without any risks of radiation. The imaging scan doesn't provide any anatomical information, so MPI will likely be combined with CT or MRI.

Source: Heart wire