System Characterization of a Highly Integrated Preclinical Hybrid MPI-MRI Scanner

Magnetic particle imaging (MPI) is a novel tracer-based in vivo imaging modality allowing quantitative measurements of the spatial distributions of superparamagnetic iron oxide (SPIO) nanoparticles in three dimensions (3D) and in real time using electromagnetic fields. However, MPI lacks the detection of morphological information which makes it difficult to unambiguously assign spatial SPIO distributions to actual organ structures. To compensate for this, a preclinical highly integrated hybrid system combining MPI and Magnetic Resonance Imaging (MRI) has been designed and gets characterized in this work. This hybrid MPI-MRI system offers a high grade of integration with respect to its hard- and software and enables sequential measurements of MPI and MRI within one seamless study and without the need for object repositioning. Therefore, time-resolved measurements of SPIO distributions acquired with MPI as well as morphological and functional information acquired with MRI can be combined with high spatial co-registration accuracy. With this initial phantom study, the feasibility of a highly integrated MPI-MRI hybrid systems has been proven successfully. This will enable dual-modal in vivo preclinical investigations of mice and rats with high confidence of success, offering the unique feature of precise MPI FOV planning on the basis of MRI data and vice versa.