A dynamic bolus phantom for the evaluation of the spatio-temporal resolution of MPI scanners

摘要

Magnetic particle imaging (MPI) is a tomographic imaging method to determine the spatial distribution of magnetic nanoparticles (MNP) within a defined volume. To evaluate the spatio-temporal resolution of existing MPI scanners, enabling the consistent comparison of the performance of different scanner setups, we developed dynamic MPI measurement phantoms based on segmented flow. These segmented flow phantoms comprise a defined bolus of ferrofluid tracer material, which can be pumped through a tube system with defined velocities. Using a hydrophobic organic carrier oil, cylindrically shaped boluses of different diameter, length, and flow velocity can be emulated. Moving boluses were imaged by different MPI scanner types and the correlation of spatial resolution und velocity of the bolus was investigated. For all bolus dimension and flow velocity combinations investigated, we observed a decreasing spatial resolution and increasing blurring for increasing bolus velocity and decreasing bolus volume.