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Chemical exchange saturation transfer magnetic resonance imaging of human knee cartilage at 3 T and 7 T

Authors

  • Anup Singh,

    Corresponding author
    1. Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
    • Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, B1 Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA 19104-6100
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  • Mohammad Haris,

    1. Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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  • Kejia Cai,

    1. Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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  • Victor B. Kassey,

    1. Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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  • Feliks Kogan,

    1. Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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  • Damodar Reddy,

    1. Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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  • Hari Hariharan,

    1. Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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  • Ravinder Reddy

    1. Center for Magnetic Resonance and Optical Imaging (CMROI), Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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Abstract

The sensitivity of chemical exchange saturation transfer (CEST) on glycosaminoglycans (GAGs) in human knee cartilage (gagCEST) in vivo was evaluated at 3 and 7 T field strengths. Calculated gagCEST values without accounting for B0 inhomogeneity (∼0.6 ppm) were >20%. After B0 inhomogeneity correction, calculated gagCEST values were negligible at 3 T and ∼6% at 7 T. These results suggest that accurate B0 correction is a prerequisite for observing reliable gagCEST. Results obtained with varying saturation pulse durations and amplitudes as well as the consistency between numerical simulations and our experimental results indicate that the negligible gagCEST observed at 3 T is due to direct saturation effects and fast exchange rate. As GAG loss from cartilage is expected to result in a further reduction in gagCEST, gagCEST method is not expected to be clinically useful at 3 T. At high fields such as 7 T, this method holds promise as a viable clinical technique. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.

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