MRI Meets MPI: A Bimodal MPI-MRI Tomograph

Abstract

While magnetic particle imaging (MPI) constitutes a novel biomedical imaging technique for tracking superparamagnetic nanoparticles in vivo, unlike magnetic resonance imaging (MRI), it cannot provide anatomical background information. Until now these two modalities have been performed in separate scanners and image co-registration has been hampered by the need to reposition the sample in both systems as similarly as possible. This paper presents a bimodal MPI-MRI-tomograph that combines both modalities in a single system.MPI and MRI images can thus be acquired without moving the sample or replacing any parts in the setup. The images acquired with the presented setup show excellent agreement between the localization of the nanoparticles in MPI and the MRI background data. A combination of two highly complementary imaging modalities has been achieved.

Multifrequency magnetic particle imaging enabled by a combined passive and active drive field feed‐through compensation approach

“…This will require the active compensation to be applicable for many frequency components, which will be implemented in the next prototype. Recent studies indicate the potential of these alternative drive field waveforms for MPI, as it can affect spatial resolution or reduce reconstruction computational load . The option to simultaneously apply multiple frequencies or use more than one frequency for image reconstruction further has great potential to increase image quality in terms of spatial resolution.…”

Traveling Wave Magnetic Particle Imaging

“…Im Falle der Messung mit zwei getrennten Scannern ist eine aufwendige Koregistrierung der Datensätze notwendig, welche mit speziellen Markern umgesetzt wird. Die ersten Ergebnisse mit einem TWMPI/LFMRI-Hybridscanner konnten Ende 2012 erfolgreich mit dem TWMPI-System demonstriert werden [25] [26]. Dabei kann eine Probe in diesem System mit beiden bildgebenden Modalitäten gemessen werden, ohne dass sie bewegt werden muss.…”

“…In den Kapiteln 3.3.5 und 5.4.4 wurde bereits die Hardware und die Ergebnisse eines MPI-MRI-Hybridscanners diskutiert und gezeigt [26]. …”

“…Die aktuelle Technik zeigt bereits Hybridsysteme wie PET/CT und PET/MR Anlagen. Die Kombination von MPI mit einer MR-Anlage konnte im Rahmen dieser Arbeit bereits gezeigt werden [26]. Eine Kombination der TWMPI-Anlage mit einer CT-Anlage ist ebenfalls denkbar.…”

Narrowband magnetic nanoparticle imaging using cooled pickup coil and gradient field

“…For this purpose, several magnetic properties of MNPs have been used, such as ac susceptibility, 1,2) magnetic relaxation, [3][4][5][6] and nonlinear magnetization. [7][8][9][10][11][12][13][14][15][16][17][18][19][20] Detection methods using nonlinear magnetization have been classified into three types, namely, harmonic-space MPI, [7][8][9][10][11][12] x-space MPI, [13][14][15] and narrowband MPI. [16][17][18][19][20] By analyzing the measured contour map, one can reconstruct an image of the spatial distribution of the MNPs.…”