Determining the resolution of a tracer for magnetic particle imaging by means of magnetic particle spectroscopy

Magnetic particle imaging (MPI) is an imaging modality to quantitatively determine the three-dimensional distribution of magnetic nanoparticles (MNPs) administered as a tracer into a biological system. Magnetic particle spectroscopy (MPS) is the zero-dimensional MPI counterpart without spatial coding but with much higher sensitivity. Generally, MPS is employed to qualitatively evaluate the MPI capability of tracer systems from the measured specific harmonic spectra. Here, we investigated the correlation of three characteristic MPS parameters with the achievable MPI resolution from a recently introduced procedure based on a two-voxel-analysis of data taken from the system function acquisition that is mandatory in Lissajous scanning MPI. We evaluated nine different tracer systems and determined their MPI capability and resolution from MPS measurements and compared the results with MPI phantom measurements.

Automated summary

Magnetic particle imaging (MPI) is an imaging technique that quantitatively determines the three-dimensional distribution of magnetic nanoparticles (MNPs) used as tracers in biological systems. Magnetic particle spectroscopy (MPS) is a zero-dimensional counterpart of MPI without spatial coding but with higher sensitivity. MPS is typically used to qualitatively evaluate the MPI capability of tracer systems based on measured harmonic spectra. In this study, we investigated the correlation between three characteristic MPS parameters and the achievable MPI resolution using a two-voxel analysis of data from the system function acquisition in Lissajous scanning MPI. We evaluated nine different tracer systems, determined their MPI capability and resolution based on MPS measurements, and compared the results with MPI phantom measurements.