5
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      High-sensitivity in vivo contrast for ultra-low field magnetic resonance imaging using superparamagnetic iron oxide nanoparticles

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Superparamagnetic nanoparticles will boost image contrast on portable MRI scanners operating at low magnetic fields.

          Abstract

          Magnetic resonance imaging (MRI) scanners operating at ultra-low magnetic fields (ULF; <10 mT) are uniquely positioned to reduce the cost and expand the clinical accessibility of MRI. A fundamental challenge for ULF MRI is obtaining high-contrast images without compromising acquisition sensitivity to the point that scan times become clinically unacceptable. Here, we demonstrate that the high magnetization of superparamagnetic iron oxide nanoparticles (SPIONs) at ULF makes possible relaxivity- and susceptibility-based effects unachievable with conventional contrast agents (CAs). We leverage these effects to acquire high-contrast images of SPIONs in a rat model with ULF MRI using short scan times. This work overcomes a key limitation of ULF MRI by enabling in vivo imaging of biocompatible CAs. These results open a new clinical translation pathway for ULF MRI and have broader implications for disease detection with low-field portable MRI scanners.

          Related collections

          Most cited references50

          • Record: found
          • Abstract: found
          • Article: not found

          Exceedingly small iron oxide nanoparticles as positive MRI contrast agents.

          Medical imaging is routine in the diagnosis and staging of a wide range of medical conditions. In particular, magnetic resonance imaging (MRI) is critical for visualizing soft tissue and organs, with over 60 million MRI procedures performed each year worldwide. About one-third of these procedures are contrast-enhanced MRI, and gadolinium-based contrast agents (GBCAs) are the mainstream MRI contrast agents used in the clinic. GBCAs have shown efficacy and are safe to use with most patients; however, some GBCAs have a small risk of adverse effects, including nephrogenic systemic fibrosis (NSF), the untreatable condition recently linked to gadolinium (Gd) exposure during MRI with contrast. In addition, Gd deposition in the human brain has been reported following contrast, and this is now under investigation by the US Food and Drug Administration (FDA). To address a perceived need for a Gd-free contrast agent with pharmacokinetic and imaging properties comparable to GBCAs, we have designed and developed zwitterion-coated exceedingly small superparamagnetic iron oxide nanoparticles (ZES-SPIONs) consisting of ∼3-nm inorganic cores and ∼1-nm ultrathin hydrophilic shell. These ZES-SPIONs are free of Gd and show a high T1 contrast power. We demonstrate the potential of ZES-SPIONs in preclinical MRI and magnetic resonance angiography.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Principles and applications of balanced SSFP techniques.

            During the past 5 years balanced steady-state free precession (SSFP) has become increasingly important for diagnostic and functional imaging. Balanced SSFP is characterized by two unique features: it offers a very high signal-to noise ratio and a T2/T1-weighted image contrast. This article focuses on the physical principles, on the signal formation, and on the resulting properties of balanced SSFP. Mechanisms for contrast modification, recent clinical application, and potential extensions of this technique are discussed.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              Low-Cost High-Performance MRI

              Magnetic Resonance Imaging (MRI) is unparalleled in its ability to visualize anatomical structure and function non-invasively with high spatial and temporal resolution. Yet to overcome the low sensitivity inherent in inductive detection of weakly polarized nuclear spins, the vast majority of clinical MRI scanners employ superconducting magnets producing very high magnetic fields. Commonly found at 1.5–3 tesla (T), these powerful magnets are massive and have very strict infrastructure demands that preclude operation in many environments. MRI scanners are costly to purchase, site, and maintain, with the purchase price approaching $1 M per tesla (T) of magnetic field. We present here a remarkably simple, non-cryogenic approach to high-performance human MRI at ultra-low magnetic field, whereby modern under-sampling strategies are combined with fully-refocused dynamic spin control using steady-state free precession techniques. At 6.5 mT (more than 450 times lower than clinical MRI scanners) we demonstrate (2.5 × 3.5 × 8.5) mm3 imaging resolution in the living human brain using a simple, open-geometry electromagnet, with 3D image acquisition over the entire brain in 6 minutes. We contend that these practical ultra-low magnetic field implementations of MRI (<10 mT) will complement traditional MRI, providing clinically relevant images and setting new standards for affordable (<$50,000) and robust portable devices.
                Bookmark

                Author and article information

                Journal
                Sci Adv
                Sci Adv
                SciAdv
                advances
                Science Advances
                American Association for the Advancement of Science
                2375-2548
                July 2020
                17 July 2020
                : 6
                : 29
                : eabb0998
                Affiliations
                [1 ]Institute of Medical Physics, School of Physics A28, University of Sydney, Sydney, NSW 2006, Australia.
                [2 ]A. A. Martinos Center for Biomedical Imaging, 149 Thirteenth St., Charlestown, MA 02129, USA.
                [3 ]ACRF Image X Institute, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia.
                [4 ]ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, NSW 2006, Australia.
                [5 ]The University of Sydney Nano Institute, Sydney, NSW 2006, Australia.
                [6 ]Department of Physics, Harvard University, 17 Oxford St., Cambridge, MA 02138, USA.
                [7 ]Harvard Medical School, 25 Shattuck St., Boston, MA 02115, USA.
                Author notes
                [* ]Corresponding author. Email: david.waddington@ 123456sydney.edu.au
                Author information
                http://orcid.org/0000-0002-7017-1556
                http://orcid.org/0000-0001-9322-7762
                http://orcid.org/0000-0002-3805-5440
                http://orcid.org/0000-0001-6765-3215
                http://orcid.org/0000-0002-7194-002X
                Article
                abb0998
                10.1126/sciadv.abb0998
                7367688
                32733998
                d60f77af-1190-4cca-9117-71d6c6961366
                Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY).

                This is an open-access article distributed under the terms of the Creative Commons Attribution license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

                History
                : 06 February 2020
                : 03 June 2020
                Funding
                Funded by: doi http://dx.doi.org/10.13039/501100001171, Cancer Institute NSW;
                Award ID: 2019/ECF1015
                Funded by: Australian Academy of Technological Sciences and Engineering;
                Funded by: University of Sydney Nano Institute;
                Categories
                Research Article
                Research Articles
                SciAdv r-articles
                Health and Medicine
                Physics
                Applied Sciences and Engineering
                Custom metadata
                Sef Rio

                Comments

                Comment on this article