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.