Non-ideal Selection Field Induced Artifacts in X-Space MPI

Ecrin Yagiz, Ahmet Rahmetullah Cagil, and Emine Ulku Saritas have published an article titled “Non-ideal Selection Field Induced Artifacts in X-Space MPI” in International Journal on Magnetic Particle Imaging. Magnetic Particle Imaging (MPI) is an emerging medical imaging modality that images the spatial distribution of superparamagnetic iron oxide (SPIO) nanoparticles using their nonlinear response to applied magnetic fields. This work demonstrates that unaccounted non-linearity of the selection field in MPI causes warping in the image reconstructed with a basic x-space approach. Unwarping algorithms can be applied to effectively address this issue, once the displacement map acting on the reconstructed image is determined. The unwarped image accurately represents the locations of nanoparticles, albeit with a resolution loss in regions away from the center of the scanner due to the degradation in selection field gradients.

 

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In magnetic particle imaging (MPI), the selection field deviates from its ideal linearity in regions away from the center of the scanner. This work demonstrates that unaccounted non-linearity of the selection field causes warping in the image reconstructed with a basic x-space approach. We also show that unwarping algorithms can be applied to effectively address this issue, once the displacement map acting on the reconstructed image is determined. The unwarped image accurately represents the locations of nanoparticles, albeit with a resolution loss in regions away from the center of the scanner due to the degradation in selection field gradients.