WAter Saturation Shift Referencing (WASSR) for chemical exchange saturation transfer experiments
By Mina Kim, J. Gillen, Bennett A. Landman, Jinyuan Zhou, P. V. van Zijl. Magnetic Resonance in Medicine, 2009
695 citations recorded by the source corpus.
Chemical exchange saturation transfer (CEST) is a contrast mechanism that exploits exchange‐based magnetization transfer (MT) between solute and water protons. CEST effects compete with direct water saturation and conventional MT processes, and generally can only be quantified through an asymmetry analysis of the water saturation spectrum (Z‐spectrum) with respect to the water frequency, a process that is exquisitely sensitive to magnetic field inhomogeneities. Here it is shown that direct water saturation imaging allows measurement of the absolute water frequency in each voxel, allowing proper centering of Z‐spectra on a voxel‐by‐voxel basis independently of spatial B0 field variations. Optimal acquisition parameters for this “water saturation shift referencing” (WASSR) approach were estimated using Monte Carlo simulations and later confirmed experimentally. The optimal ratio of the WASSR sweep width to the linewidth of the direct saturation curve was found to be 3.3–4.0, requiring a sampling of 16–32 points. The frequency error was smaller than 1 Hz at signal‐to‐noise ratios of 40 or higher. The WASSR method was applied to study glycogen, where the chemical shift difference between the hydroxyl (OH) protons and bulk water protons at 3T is so small (0.75–1.25 ppm) that the CEST spectrum is inconclusive without proper referencing. Magn Reson Med, 2008. © 2009 Wiley‐Liss, Inc.
Subfields: Materials Chemistry, Radiology, Nuclear Medicine and Imaging
View Paper: https://www.semanticscholar.org/paper/97878fb5416ad612bf8db27feea97c8b5c3b555c
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In Materials Chemistry
- Peter C. M. van Zijl
- N. Yadav
- P. V. Zijl
- Jiadi Xu
- Wilfred Lam
- Linda Knutsson
- Greg J. Stanisz
- Jinyuan Zhou
In Radiology, Nuclear Medicine and Imaging
- Peter C. M. van Zijl
- N. Yadav
- P. V. Zijl
- Jiadi Xu
- Wilfred Lam
- Linda Knutsson
- Greg J. Stanisz
- Craig K. Jones
Citations in the corpus
- Chemical Exchange Saturation Transfer (CEST): what is in a name and what isn’t? (2011, methodology): “This problem can be addressed with the aid of the WASSR approach (83), which allows such detection even at 3 T.”
- Nuclear Overhauser Enhancement (NOE) Imaging in the Human Brain at 7 T (2013, positive): “…a region of interest were each shifted using amodified shift correction (Jones et al., 2012) based on the water saturation shift referencing (WASSR, (Kim et al., 2009)) approach in order to reset the water signal to 0 ppm for each voxel after which the corrected Z-spectra were averaged together.”
- Magnetization Transfer Contrast and Chemical Exchange Saturation Transfer MRI. Features and Analysis of the Field-Dependent Saturation Spectrum (2017, methodology): “Alternatively, and more accurately, a separate B0 assessment can be acquired, for instance using a low saturation power scan with frequency offsets centered closely about the water resonance in a technique known as water saturation shift referencing (WASSR) (Kim et al., 2009), a B0 map with every fr”