Improving MRI differentiation of gray and white matter in epileptogenic lesions based on nonlinear feedback

Authors

  • Susie Y. Huang,

    1. Department of Chemistry and Biochemistry, University of California–Los Angeles, Los Angeles, California, USA
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  • Stephanie M. Wolahan,

    1. Department of Chemistry and Biochemistry, University of California–Los Angeles, Los Angeles, California, USA
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  • Gary W. Mathern,

    1. Division of Neurosurgery, David Geffen School of Medicine, University of California–Los Angeles, Los Angeles, California, USA
    2. Mental Retardation Research Center, David Geffen School of Medicine, University of California–Los Angeles, Los Angeles, California, USA
    3. Brain Research Institute, University of California–Los Angeles, Los Angeles, California, USA
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  • Dennis J. Chute,

    1. Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California–Los Angeles, Los Angeles, California, USA
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  • Massoud Akhtari,

    1. Neuropsychiatric Institute, University of California–Los Angeles, Los Angeles, California, USA
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  • Snow T. Nguyen,

    1. Division of Neurosurgery, David Geffen School of Medicine, University of California–Los Angeles, Los Angeles, California, USA
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  • My N. Huynh,

    1. Division of Neurosurgery, David Geffen School of Medicine, University of California–Los Angeles, Los Angeles, California, USA
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  • Noriko Salamon,

    1. Division of Neuroradiology, David Geffen School of Medicine, University of California–Los Angeles, Los Angeles, California, USA
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  • Yung-Ya Lin

    Corresponding author
    1. Department of Chemistry and Biochemistry, University of California–Los Angeles, Los Angeles, California, USA
    • Department of Chemistry and Biochemistry, University of California–Los Angeles, 607 Charles E. Young Dr. East, Los Angeles, CA 90095-1569
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Abstract

A new method for enhancing MRI contrast between gray matter (GM) and white matter (WM) in epilepsy surgery patients with symptomatic lesions is presented. This method uses the radiation damping feedback interaction in high-field MRI to amplify contrast due to small differences in resonance frequency in GM and WM corresponding to variations in tissue susceptibility. High-resolution radiation damping-enhanced (RD) images of in vitro brain tissue from five patients were acquired at 14 T and compared with corresponding conventional T1-, Tmath image-, and proton density (PD)-weighted images. The RD images yielded a six times better contrast-to-noise ratio (CNR = 44.8) on average than the best optimized T1-weighted (CNR = 7.92), Tmath image-weighted (CNR = 4.20), and PD-weighted images (CNR = 2.52). Regional analysis of the signal as a function of evolution time and initial pulse flip angle, and comparison with numerical simulations confirmed that radiation damping was responsible for the observed signal growth. The time evolution of the signal in different tissue regions was also used to identify subtle changes in tissue composition that were not revealed in conventional MR images. RD contrast is compared with conventional MR methods for separating different tissue types, and its value and limitations are discussed. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc.

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