A new method for detecting exchanging amide protons using chemical exchange rotation transfer

Authors

  • Zhongliang Zu,

    1. Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
    2. Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
    Search for more papers by this author
  • Vaibhav A. Janve,

    1. Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
    2. Deparment of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA
    Search for more papers by this author
  • Junzhong Xu,

    1. Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
    2. Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
    Search for more papers by this author
  • Mark D. Does,

    1. Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
    2. Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
    3. Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
    4. Department of Electrical Engineering, Vanderbilt University, Nashville, Tennessee, USA
    Search for more papers by this author
  • John C. Gore,

    1. Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
    2. Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
    3. Deparment of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA
    4. Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
    5. Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
    Search for more papers by this author
  • Daniel F. Gochberg

    Corresponding author
    1. Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
    2. Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
    3. Deparment of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA
    • Vanderbilt University Institute of Imaging Science, 1161 21st Ave. S, Medical Center North, AAA-3112, Nashville, TN 37232-2310
    Search for more papers by this author

Abstract

In this study, we introduce a new method for amide proton transfer imaging based on chemical exchange rotation transfer. It avoids several artifacts that plague conventional chemical exchange saturation transfer approaches by creating label and reference scans based on varying the irradiation pulse rotation angle (π and 2π radians) instead of the frequency offset (3.5 and −3.5 ppm). Specifically, conventional analysis is sensitive to confounding contributions from magnetic field (B0) inhomogeneities and, more problematically, inherently asymmetric macromolecular resonances. In addition, the lipid resonance at −3.5 ppm complicates the interpretation of the reference scan and decreases the resulting contrast. Finally, partial overlap of the amide signal by nearby amines and hydroxyls obscure the results. By avoiding these issues, our new method is a promising approach for imaging endogenous protein and peptide content and mapping pH. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.

Ancillary