Adrienne N. Dula1, Richard D. Dortch1,
Bennett A. Landman2, Edward B. Welch, 1,3, John C. Gore1,
Seth A. Smith1
1Vanderbilt Institute of Imaging
Science, Vanderbilt University, Nashville, TN, United States; 2Radiology
and Radiological Sciences, Vanderbilt Medical Center, Nashville, TN, United
States; 33MR Clinical Science, Philips Healthcare, Cleveland, OH,
United States
Chemical
exchange saturation transfer (CEST) imaging is a molecular MRI technique that
detects endogenous mobile protons via saturation transfer. Amide proton transfer
(APT), a type of CEST imaging, probes amide protons in the peptide
bondsallowing MRI quantification through asymmetry analysis of the
z-spectrum. Translation to 7T brings
sensitivity to magnetic field inhomogeneities. Water saturation shift referencing
(WASSR) uses direct water saturation to determine the frequency shift due to field
inhomogeneities producing symmetric spectra with negligible field
inhomogeneities, MT, or CEST interference. This study evaluates compares
WASSR to high-order fitting to determine the center frequency at 7T.