Artifact Analysis for Axially Elongated Lissajous Trajectories in Magnetic Particle Imaging

Magnetic Particle Imaging promises great potential for various imaging scenarios with medical purpose. In order to meet this potential, one of the key factors is that the size and the shape of the sampling area need to be adaptable to the aimed applications. An interesting approach to achieve this within medical and technical safety limits is by use of focus fields. However, even with current focus-field approaches, an enlargement in axial direction remains a challenging task. Recently, a use of an elongated sampling trajectory was proposed to address this challenge. Such an elongation can be achieved either by superimposing an orthogonal oriented linear focus field to a 2D trajectory or by an additional continuous movement in axial direction. The resulting elongated trajectory allows for a larger axial coverage of a scanned object. However, based on the physical properties of the signal generation, the elongation length needs to be limited to avoid signal loss or the occurrence of artifacts. In this work, a simulation based artifact analysis is carried out for Lissajous trajectories to determine an elongation limit that allows for both, the avoidance of signal loss and artifacts.