Positron emission tomography studies of cerebral glucose metabolism in chronic partial epilepsy

Authors

  • Bassel W. Abou-Khalil,

    MD
    1. Department of Neurology, Division of Nuclear Medicine, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI 48109
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  • Dr George J. Siegel,

    MD, Corresponding author
    1. Department of Neurology, Division of Nuclear Medicine, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI 48109
    • Department of Neurology, Neuroscience Bldg, 1103 E Huron St, University of Michigan, Ann Arbor, MI 48109
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  • J. Chris Sackellares,

    MD
    1. Department of Neurology, Division of Nuclear Medicine, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI 48109
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  • Sid Gilman,

    MD
    1. Department of Neurology, Division of Nuclear Medicine, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI 48109
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  • Richard Hichwa PhD,

    1. PET/Cyclotron Facility, Division of Nuclear Medicine, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI 48109
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  • Robert Marshall MS

    1. Department of Neurology, Division of Nuclear Medicine, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, MI 48109
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Abstract

Positron emission tomography (PET) performed with {18F}-2-fluoro-2-deoxy-D-glucose ({18F}FDG) was used to measure local cerebral metabolic rate for glucose (lCMRGlc) interictally in 31 patients with chronic partial epilepsy and 16 age-matched normal subjects. Hypometabolic zones were visualized in 25 patients (81%). Cortical lCMRGlc in hypometabolic zones was within 2 standard deviations of the mean for normal temporal cortex in all but 8 patients. However, in 24 patients asymmetry between the hypometabolic cortex and homologous contralateral cortex was more than 2 standard deviations above the mean cortical asymmetry for normals. There was good correlation between hypometabolic zones and electroencephalogram (EEG) foci in patients with unilateral well-defined EEG foci. Diffuse or shifting EEG abnormalities were often associated with normal PET scans. Of 28 patients who underwent magnetic resonance imaging, 10 showed focal temporal lobe abnormalities corresponding to focal hypometabolism. While the {18F}FDG PET scan cannot currently localize an epileptogenic zone independently, the absence of focal hypometabolism or its presence contralateral to a presumed EEG focus suggests the need for additional electrophysiological data.

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