Signal alterations of glutamate-weighted chemical exchange saturation transfer MRI in lysophosphatidylcholine-induced demyelination in the rat brain.

ABSTRACT

PURPOSE: To compare in vivo glutamate-weighted chemical exchange saturation transfer (GluCEST-weighted) signal changes between in a rat model of demyelinated multiple sclerosis and control groups. PROCEDURES Using a pre-clinical 7 T magnetic resonance imaging (MRI) system, CEST imaging was applied to a toxin (lysophosphatidylcholine; LPC) induced rat (MSLPC) and control (CTRL) groups to compare in vivo glutamate signal changes. The GluCEST-weighted signals were analyzed based on the magnetization transfer ratio asymmetry approach at 3.0 ppm on the region-of-interests (ROIs) in the corpus callosum and hippocampus at each hemispheric region. RESULTS: GluCEST-weighted signals were significantly changed between the CTRL and MSLPC groups, while higher glutamate signals were indicated in the MSLPC than the CTRL group ([MSLPC / CTRL]; hippocampus [6.159 ± 0.790 / 4.336 ± 0.446] and corpus callosum [-3.545 ± 0.945 / -6.038 ± 0.620], all p = 0.001). CONCLUSIONS: Our results show increased GluCEST-weighted signals in the LPC-induced demyelination rat brain compared with control. GluCEST-weighted imaging could be a useful tool for defining a biomarker to estimate the glutamate-related metabolism in MS.