Bulk magnetic susceptibility effects on the assessment of intra- and extramyocellular lipids in vivo

Authors

  • Lidia S. Szczepaniak,

    Corresponding author
    1. Department of Radiology, University of Texas, Southwestern Medical Center at Dallas, Dallas, Texas
    2. Department of Internal Medicine, University of Texas, Southwestern Medical Center at Dallas, Dallas, Texas
    • Division of Hypertension, Department of Internal Medicine, University of Texas, Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., J4.134, Dallas, TX 75390-8586
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  • Robert L. Dobbins,

    1. Department of Internal Medicine, University of Texas, Southwestern Medical Center at Dallas, Dallas, Texas
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  • Daniel T. Stein,

    1. Albert Einstein College of Medicine, Bronx, New York
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  • J. Denis McGarry

    1. Department of Internal Medicine, University of Texas, Southwestern Medical Center at Dallas, Dallas, Texas
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Abstract

Localized proton spectroscopy provides a novel method for noninvasive measurement of lipid content in skeletal muscle. It has been suggested that the chemical shift difference between lipid signals from distinct compartments in skeletal muscle might be caused by bulk magnetic susceptibility (BMS) differences from lipids stored in intra- (IMCL) and extramyocellular (EMCL) compartments. Direct evidence is provided to confirm the theoretical prediction that compartment symmetry is responsible for discrimination between resonances of IMCL and EMCL. Phantoms imitating lipids in skeletal muscle were constructed using soybean oil to represent EMCL, and Intralipid™, an intravenous fat emulsion of fine droplets, to represent IMCL. It was found that the chemical shift of Intralipid™ is independent of the BMS effects, while the resonance of soybean oil shifts in a predictable manner determined by the geometry of the compartment. Magn Reson Med 47:607–610, 2002. © 2002 Wiley-Liss, Inc.

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