Karin Shmueli1,
Stephen J. Dodd2, Christian Wunder3, Jeff H. Duyn1
1Advanced MRI
Section, Laboratory of Functional & Molecular Imaging, National Institute
of Neurological Disorders & Stroke, National Institutes of Health,
Bethesda, MD, USA; 2Functional & Molecular Metabolism Section,
Laboratory of Functional & Molecular Imaging, National Institute of
Neurological Disorders & Stroke, National Institutes of Health, Bethesda,
MD, USA; 3Traffic, Signaling & Delivery Laboratory, Curie
Institute, France
Substantial positive white-gray matter (WM-GM) exchange-induced frequency shifts (fx) have been measured in brain tissue. Cerebrosides are proposed to contribute because they are more abundant in WM than GM. We measured fx due to cerebrosides at six concentrations in an in-vitro model for WM cell membranes by performing chemical shift imaging experiments using dioxane as a reference chemical. fx increased linearly with cerebroside concentration (0.18 ppb/mM). Together with the human WM-GM difference in cerebroside content, this suggests that cerebrosides could account for much of the measured WM-GM fx. These findings should aid in interpreting MR frequency contrast.
Keywords