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Bakenecker AC, Ahlborg M, Debbeler C, Kaethner C, Buzug TM, Lüdtke-Buzug K. Magnetic particle imaging in vascular medicine. Innov Surg Sci 2018; 3:179-192. [PMID: 31579782 PMCID: PMC6604583 DOI: 10.1515/iss-2018-2026] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 09/14/2018] [Indexed: 01/31/2023] Open
Abstract
Magnetic particle imaging (MPI) is a new medical imaging technique that enables three-dimensional real-time imaging of a magnetic tracer material. Although it is not yet in clinical use, it is highly promising, especially for vascular and interventional imaging. The advantages of MPI are that no ionizing radiation is necessary, its high sensitivity enables the detection of very small amounts of the tracer material, and its high temporal resolution enables real-time imaging, which makes MPI suitable as an interventional imaging technique. As MPI is a tracer-based imaging technique, functional imaging is possible by attaching specific molecules to the tracer material. In the first part of this article, the basic principle of MPI will be explained and a short overview of the principles of the generation and spatial encoding of the tracer signal will be given. After this, the used tracer materials as well as their behavior in MPI will be introduced. A subsequent presentation of selected scanner topologies will show the current state of research and the limitations researchers are facing on the way from preclinical toward human-sized scanners. Furthermore, it will be briefly shown how to reconstruct an image from the tracer materials' signal. In the last part, a variety of possible future clinical applications will be presented with an emphasis on vascular imaging, such as the use of MPI during cardiovascular interventions by visualizing the instruments. Investigations will be discussed, which show the feasibility to quantify the degree of stenosis and diagnose strokes and traumatic brain injuries as well as cerebral or gastrointestinal bleeding with MPI. As MPI is not only suitable for vascular medicine but also offers a broad range of other possible applications, a selection of those will be briefly presented at the end of the article.
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Affiliation(s)
- Anna C. Bakenecker
- Institute of Medical Engineering, University of Luebeck, Luebeck, Germany
| | - Mandy Ahlborg
- Institute of Medical Engineering, University of Luebeck, Luebeck, Germany
| | - Christina Debbeler
- Institute of Medical Engineering, University of Luebeck, Luebeck, Germany
| | - Christian Kaethner
- Institute of Medical Engineering, University of Luebeck, Luebeck, Germany
| | - Thorsten M. Buzug
- Institute of Medical Engineering, University of Luebeck, Luebeck, Germany
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Malhotra A, Spieß F, Stegelmeier C, Debbeler C, Lüdtke-Buzug K. Effect of key parameters on synthesis of superparamagnetic nanoparticles (SPIONs). Current Directions in Biomedical Engineering 2016. [DOI: 10.1515/cdbme-2016-0117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
There are various methods to synthesize superparamagnetic nanoparticles (SPIONs) useful for MPI (magnetic particle imaging) and in therapy (Hypothermia) such as co-precipitation, hydrothermal reactions etc. In this research, the focus is to analyse the effects of crucial parameters such as effect of molecular mass of dextran and temperature of the co-precipitation. These parameters play a crucial role in the inherent magnetic properties of the resulting SPIONs. The amplitude spectrum and hysteresis curve of the SPIONs is analysed with MPS (magnetic particle spectrometer). PCCS (photon cross-correlation spectroscopy) measurements are done to analyse the size distribution of hydrodynamic diameter the resulting SPIONs.
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Affiliation(s)
- Ankit Malhotra
- Institute of Medical Engineering (IMT), University of Luebeck, Building 64, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Felix Spieß
- Institute of Medical Engineering (IMT), University of Luebeck, Building 64, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Corinna Stegelmeier
- Institute of Medical Engineering (IMT), University of Luebeck, Building 64, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Christina Debbeler
- Institute of Medical Engineering (IMT), University of Luebeck, Building 64, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Kerstin Lüdtke-Buzug
- Institute of Medical Engineering (IMT), University of Luebeck, Building 64, Ratzeburger Allee 160, 23562 Lübeck, Germany
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Panagiotopoulos N, Duschka RL, Ahlborg M, Bringout G, Debbeler C, Graeser M, Kaethner C, Lüdtke-Buzug K, Medimagh H, Stelzner J, Buzug TM, Barkhausen J, Vogt FM, Haegele J. Magnetic particle imaging: current developments and future directions. Int J Nanomedicine 2015; 10:3097-114. [PMID: 25960650 PMCID: PMC4411024 DOI: 10.2147/ijn.s70488] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Magnetic particle imaging (MPI) is a novel imaging method that was first proposed by Gleich and Weizenecker in 2005. Applying static and dynamic magnetic fields, MPI exploits the unique characteristics of superparamagnetic iron oxide nanoparticles (SPIONs). The SPIONs’ response allows a three-dimensional visualization of their distribution in space with a superb contrast, a very high temporal and good spatial resolution. Essentially, it is the SPIONs’ superparamagnetic characteristics, the fact that they are magnetically saturable, and the harmonic composition of the SPIONs’ response that make MPI possible at all. As SPIONs are the essential element of MPI, the development of customized nanoparticles is pursued with the greatest effort by many groups. Their objective is the creation of a SPION or a conglomerate of particles that will feature a much higher MPI performance than nanoparticles currently available commercially. A particle’s MPI performance and suitability is characterized by parameters such as the strength of its MPI signal, its biocompatibility, or its pharmacokinetics. Some of the most important adjuster bolts to tune them are the particles’ iron core and hydrodynamic diameter, their anisotropy, the composition of the particles’ suspension, and their coating. As a three-dimensional, real-time imaging modality that is free of ionizing radiation, MPI appears ideally suited for applications such as vascular imaging and interventions as well as cellular and targeted imaging. A number of different theories and technical approaches on the way to the actual implementation of the basic concept of MPI have been seen in the last few years. Research groups around the world are working on different scanner geometries, from closed bore systems to single-sided scanners, and use reconstruction methods that are either based on actual calibration measurements or on theoretical models. This review aims at giving an overview of current developments and future directions in MPI about a decade after its first appearance.
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Affiliation(s)
- Nikolaos Panagiotopoulos
- Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, Germany
| | - Robert L Duschka
- Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, Germany
| | - Mandy Ahlborg
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - Gael Bringout
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | | | - Matthias Graeser
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | | | | | - Hanne Medimagh
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - Jan Stelzner
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - Thorsten M Buzug
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - Jörg Barkhausen
- Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, Germany
| | - Florian M Vogt
- Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, Germany
| | - Julian Haegele
- Clinic for Radiology and Nuclear Medicine, University Hospital Schleswig Holstein, Campus Lübeck, Germany
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Müller HH, Ptaszynski L, Schlott K, Debbeler C, Bever M, Koinzer S, Birngruber R, Brinkmann R, Hüttmann G. Imaging thermal expansion and retinal tissue changes during photocoagulation by high speed OCT. Biomed Opt Express 2012; 3:1025-46. [PMID: 22567594 PMCID: PMC3342180 DOI: 10.1364/boe.3.001025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 03/29/2012] [Accepted: 04/02/2012] [Indexed: 05/04/2023]
Abstract
Visualizing retinal photocoagulation by real-time OCT measurements may considerably improve the understanding of thermally induced tissue changes and might enable a better reproducibility of the ocular laser treatment. High speed Doppler OCT with 860 frames per second imaged tissue changes in the fundus of enucleated porcine eyes during laser irradiation. Tissue motion, measured by Doppler OCT with nanometer resolution, was correlated with the temperature increase, which was measured non-invasively by optoacoustics. In enucleated eyes, the increase of the OCT signal near the retinal pigment epithelium (RPE) corresponded well to the macroscopically visible whitening of the tissue. At low irradiance, Doppler OCT revealed additionally a reversible thermal expansion of the retina. At higher irradiance additional movement due to irreversible tissue changes was observed. Measurements of the tissue expansion were also possible in vivo in a rabbit with submicrometer resolution when global tissue motion was compensated. Doppler OCT may be used for spatially resolved measurements of retinal temperature increases and thermally induced tissue changes. It can play an important role in understanding the mechanisms of photocoagulation and, eventually, lead to new strategies for retinal laser treatments.
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Affiliation(s)
- Heike H. Müller
- Institute of Biomedical Optics, University of Lübeck, Peter-Monnik-Weg 4, Lübeck,
Germany
- Medical Laser Center Lübeck GmbH, Peter-Monnik-Weg 4, Lübeck,
Germany
| | - Lars Ptaszynski
- Medical Laser Center Lübeck GmbH, Peter-Monnik-Weg 4, Lübeck,
Germany
| | - Kerstin Schlott
- Institute of Biomedical Optics, University of Lübeck, Peter-Monnik-Weg 4, Lübeck,
Germany
| | - Christina Debbeler
- Institute of Biomedical Optics, University of Lübeck, Peter-Monnik-Weg 4, Lübeck,
Germany
| | - Marco Bever
- Medical Laser Center Lübeck GmbH, Peter-Monnik-Weg 4, Lübeck,
Germany
| | - Stefan Koinzer
- Dept. of Ophthalmology, University Medical Center of Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Kiel,
Germany
| | - Reginald Birngruber
- Institute of Biomedical Optics, University of Lübeck, Peter-Monnik-Weg 4, Lübeck,
Germany
- Medical Laser Center Lübeck GmbH, Peter-Monnik-Weg 4, Lübeck,
Germany
| | - Ralf Brinkmann
- Institute of Biomedical Optics, University of Lübeck, Peter-Monnik-Weg 4, Lübeck,
Germany
- Medical Laser Center Lübeck GmbH, Peter-Monnik-Weg 4, Lübeck,
Germany
| | - Gereon Hüttmann
- Institute of Biomedical Optics, University of Lübeck, Peter-Monnik-Weg 4, Lübeck,
Germany
- Medical Laser Center Lübeck GmbH, Peter-Monnik-Weg 4, Lübeck,
Germany
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