MRI of regular-shaped cell-encapsulating polyhedral microcontainers

Authors

  • Barjor Gimi,

    Corresponding author
    1. Department of Radiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
    2. Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine; Baltimore, Maryland, USA
    • Department of Radiology, The University of Texas Southwestern Medical Center at Dallas, 1935 Motor Street, P1-407, Dallas, TX 75235
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  • Dmitri Artemov,

    1. Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine; Baltimore, Maryland, USA
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  • Timothy Leong,

    1. Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
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  • David H. Gracias,

    1. Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
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  • Zaver M. Bhujwalla

    1. Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine; Baltimore, Maryland, USA
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Abstract

We devised cubic and pyramidal microcontainers for cell encapsulation. While the cube is easier to manipulate, the pyramid offers a higher surface area-to-volume ratio and may therefore provide the encapsulated cells with increased access to nutrients. To discern the microcontainers' implant location and environment, and to aid in image-guided therapy, we showed noninvasive detection of microcontainers using MRI. Diamagnetic microcontainers were imaged using the radio frequency (RF) shielding effect, with negative contrast localized to the interior of the microcontainers. For applications in which it is difficult to distinguish the microcontainers from other hypointensities, positive contrast can be used to discern them. We showed positive-contrast MRI of a diamagnetic microcontainer. To image microcontainers that are smaller than the spatial resolution of MRI, we performed in vivo negative-contrast MRI of a ferromagnetic microcontainer. As opposed to the diamagnetic microcontainer, the ferromagnetic microcontainer created a region of MRI contrast several times larger than the microcontainer's dimensions. Magn Reson Med, 2007. © 2007 Wiley-Liss, Inc.

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