Magnetic particle imaging: Introduction to imaging and hardware realization

Buzug, Thorsten M.; Bringout, Gaël; Erbe, Marlitt; Gräfe, Ksenija; Graeser, Matthias; Grüttner, Mandy; Halkola, A.; Sattel, Timo F.; Tenner, W.; Wojtczyk, Hanne; Haegele, Julian; Vogt, Florian; Barkhausen, Jörg; Lüdtke‐Buzug, Kerstin

doi:10.1016/j.zemedi.2012.07.004

Cited by 80 publications

(43 citation statements)

References 56 publications

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“…A very elegant method would be the use of superparamagnetic iron oxide nanoparticles that can be visualized by magnetic particle imaging (MPI) [23]. MPI is a new imaging modality that promises high sensitivity, resolution and imaging speed [24]. MPI enables a resolution of <1 mm [25], is noninvasive and does not involve exposure to high energy radiation or radioactive contrast agents, which are detrimental to patient compliance in screening programs.…”

Section: Discussionmentioning

confidence: 99%

Absence of the Epithelial Glycocalyx As Potential Tumor Marker for the Early Detection of Colorectal Cancer

et al. 2016

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Detection of cancer at an early stage is pivotal for successful treatment and long term survival, yet early diagnosis requires sensitive and specific markers that can be easily detected by screening procedures. Differences in the surface structure of tumor and healthy cells, if sufficiently pronounced and discernible, may serve that purpose. We analyzed the luminal surface of healthy and neoplastic human colorectal tissues for the presence and architecture of the glycocalyx—a dense network of highly glycosylated proteins—using transmission electron microscopy. The ultrastructural analyses showed that 93% of healthy mucosae were covered by an intact glycocalyx. Contrarily, on over 90% of the surface of neoplastic cells the glycocalyx was absent. The sensitivity and specificity of our marker “absence of a glycocalyx” are excellent, being 91% (83–96%) and 96% (89–99%) for adenocarcinomas and 94% (73–100%) and 92% (85–97%) for precancerous polyps (means and 95% confidence intervals). Using a cell culture model we could demonstrate that a particulate probe targeting a cell surface receptor usually concealed beneath the glycocalyx can bind selectively to glycocalyx-free areas of a tumor cell layer. We propose that the absence of a glycocalyx may serve as novel type of tumor marker. If the absence of the glycocalyx can be detected e.g. via binding of imaging probes to non-shielded surface receptors of anomalously differentiated cells, this tumor marker could be used to enable early diagnosis of colorectal cancer.

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Section: Discussionmentioning

confidence: 99%

Absence of the Epithelial Glycocalyx As Potential Tumor Marker for the Early Detection of Colorectal Cancer

et al. 2016

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“…To enable spatial encoding of the information, a static magnetic gradient field, also known as the selection field, is utilized in MPI. This field contains a spatial location named a field-free point (FFP) that has zero field magnitude, and only the particles located at the FFP induce the MPI signal in the receive coils [6–8]. …”

Section: Introductionmentioning

confidence: 99%

An Analytical Approach for Fast Recovery of the LSI Properties in Magnetic Particle Imaging

Asl

Yoon

2016

International Journal of Biomedical Imaging

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Linearity and shift invariance (LSI) characteristics of magnetic particle imaging (MPI) are important properties for quantitative medical diagnosis applications. The MPI image equations have been theoretically shown to exhibit LSI; however, in practice, the necessary filtering action removes the first harmonic information, which destroys the LSI characteristics. This lost information can be constant in the x-space reconstruction method. Available recovery algorithms, which are based on signal matching of multiple partial field of views (pFOVs), require much processing time and a priori information at the start of imaging. In this paper, a fast analytical recovery algorithm is proposed to restore the LSI properties of the x-space MPI images, representable as an image of discrete concentrations of magnetic material. The method utilizes the one-dimensional (1D) x-space imaging kernel and properties of the image and lost image equations. The approach does not require overlapping of pFOVs, and its complexity depends only on a small-sized system of linear equations; therefore, it can reduce the processing time. Moreover, the algorithm only needs a priori information which can be obtained at one imaging process. Considering different particle distributions, several simulations are conducted, and results of 1D and 2D imaging demonstrate the effectiveness of the proposed approach.

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“…First, in vivo experiments performed with mice have demonstrated that this technique is able to acquire data with high sensitivity, high resolution, and high speed [2], [3].…”

Section: Introductionmentioning

confidence: 99%

Performance of Shielded Electromagnet-Evaluation Under Low-Frequency Excitation

2015

Self Cite

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Methods to evaluate the eddy current amplitude induced in a shield are presented. This is used to assess the effect of those currents on the efficiency of coils in an magnetic particle imaging scanner. The example of a shielded drive coil is introduced and a finite element method and a boundary element method are used to evaluate the loss of efficiency of the coil when operated with ac signals. The calculation needed to implement the boundary element method is detailed, which offers an analytic representation of the phenomena. This, in turn, improves the available knowledge to make design decision at the scanner level. The results of both methods are found to be similar, when the fields generated by a coil with different shields are compared. However, the calculation cost of the boundary element method is far inferior. The boundary element method calculation shows that, besides the used frequency, the geometry of the system, and the shielding material, there is little to be done to increase the shielded-coil performance. In addition, the results for this methods may be integrated into an optimization scheme to integrate them for the design of coils.Index Terms-Boundary element method (BEM), eddy current, electromagnet design, finite element method (FEM), magnetic particle imaging (MPI), shielding.

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Magnetic particle imaging: Introduction to imaging and hardware realization

Cited by 80 publications

References 56 publications

Absence of the Epithelial Glycocalyx As Potential Tumor Marker for the Early Detection of Colorectal Cancer

Absence of the Epithelial Glycocalyx As Potential Tumor Marker for the Early Detection of Colorectal Cancer

An Analytical Approach for Fast Recovery of the LSI Properties in Magnetic Particle Imaging

Performance of Shielded Electromagnet-Evaluation Under Low-Frequency Excitation

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