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Development of chemical exchange saturation transfer at 7T
Author(s) -
Dula Adrienne N.,
Asche Elizabeth M.,
Landman Bennett A.,
Welch E. Brian,
Pawate Siddharama,
Sriram Subramaniam,
Gore John C.,
Smith Seth A.
Publication year - 2011
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.22862
Subject(s) - white matter , magnetization transfer , voxel , nuclear magnetic resonance , chemistry , saturation (graph theory) , multiple sclerosis , asymmetry , nuclear medicine , magnetic resonance imaging , medicine , radiology , physics , mathematics , combinatorics , quantum mechanics , psychiatry
Abstract Chemical exchange saturation transfer (CEST) MRI is a molecular imaging method that has previously been successful at reporting variations in tissue protein and glycogen contents and pH. We have implemented amide proton transfer (APT), a specific form of chemical exchange saturation transfer imaging, at high field (7T) and used it to study healthy human subjects and patients with multiple sclerosis. The effects of static field inhomogeneities were mitigated using a water saturation shift referencing method to center each z‐spectrum on a voxel‐by‐voxel basis. Contrary to results obtained at lower fields, APT imaging at 7T revealed significant contrast between white and gray matters, with a higher APT signal apparent within the white matter. Preliminary studies of multiple sclerosis showed that the APT asymmetry varied with the type of lesion examined. An increase in APT asymmetry relative to healthy tissue was found in some lesions. These results indicate the potential utility of APT at high field as a noninvasive biomarker of white matter pathology, providing complementary information to other MRI methods in current clinical use. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.