Automated detection and characterization of SPIO-labeled cells and capsules using magnetic field perturbations

Authors

  • Parker H. Mills,

    1. Department of Biological Sciences and Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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  • T. Kevin Hitchens,

    1. Department of Biological Sciences and Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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  • Lesley M. Foley,

    1. Department of Biological Sciences and Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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  • Thomas Link,

    1. Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    2. Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    3. Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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  • Qing Ye,

    1. Department of Biological Sciences and Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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  • Clifford R. Weiss,

    1. Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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  • Joe D. Thompson,

    1. Division of Materials Science & Technology, Group 10, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
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  • Wesley D. Gilson,

    1. Siemens Corporate Research, Baltimore, Maryland, USA
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  • Aravind Arepally,

    1. Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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  • John A. Melick,

    1. Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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  • Patrick M. Kochanek,

    1. Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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  • Chien Ho,

    1. Department of Biological Sciences and Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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  • Jeff W. M. Bulte,

    1. Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    2. Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    3. Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    4. Department of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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  • Eric T. Ahrens

    Corresponding author
    1. Department of Biological Sciences and Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
    • Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213
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Abstract

Understanding how individual cells behave inside living systems will help enable new diagnostic tools and cellular therapies. Superparamagnetic iron oxide particles can be used to label cells and theranostic capsules for noninvasive tracking using MRI. Contrast changes from superparamagnetic iron oxide are often subtle relative to intrinsic sources of contrast, presenting a detection challenge. Here, we describe a versatile postprocessing method, called Phase map cross-correlation Detection and Quantification (PDQ), that automatically identifies localized deposits of superparamagnetic iron oxide, estimating their volume magnetic susceptibility and magnetic moment. To demonstrate applicability, PDQ was used to detect and characterize superparamagnetic iron oxide-labeled magnetocapsules implanted in porcine liver and suspended in agarose gel. PDQ was also applied to mouse brains infiltrated by MPIO-labeled macrophages following traumatic brain injury; longitudinal, in vivo studies tracked individual MPIO clusters over 3 days, and tracked clusters were corroborated in ex vivo brain scans. Additionally, we applied PDQ to rat hearts infiltrated by MPIO-labeled macrophages in a transplant model of organ rejection. PDQ magnetic measurements were signal-to-noise ratio invariant for images with signal-to-noise ratio > 11. PDQ can be used with conventional gradient-echo pulse sequences, requiring no extra scan time. The method is useful for visualizing biodistribution of cells and theranostic magnetocapsules and for measuring their relative iron content. Magn Reson Med, 2011. © 2011 Wiley-Liss, Inc.

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